title:
On turning waves for the inhomogeneous Muskat problem: a
  computer-assisted proof

abstract:
  We exhibit a family of graphs that develop turning singularities (i.e. their
Lipschitz seminorm blows up and they cease to be a graph, passing from the
stable to the unstable regime) for the inhomogeneous, two-phase Muskat problem
where the permeability is given by a nonnegative step function. We study the
influence of different choices of the permeability and different boundary
conditions (both at infinity and considering finite/infinite depth) in the
development or prevention of singularities for short time. In the general case
(inhomogeneous, confined) we prove a bifurcation diagram concerning the
appearance or not of singularities when the depth of the medium and the
permeabilities change. The proofs are carried out using a combination of
classical analysis techniques and computer-assisted verification.


title: Gene-Proximity Models For Genome-Wide Association Studies

abstract:
  Motivated by the important problem of detecting association between genetic
markers and binary traits in genome-wide association studies, we present a
novel Bayesian model that establishes a hierarchy between markers and genes by
defining weights according to gene lengths and distances from genes to markers.
The proposed hierarchical model uses these weights to define unique prior
probabilities of association for markers based on their proximities to genes
that are believed to be relevant to the trait of interest. We use an
expectation-maximization algorithm in a filtering step to first reduce the
dimensionality of the data and then sample from the posterior distribution of
the model parameters to estimate posterior probabilities of association for the
markers. We offer practical and meaningful guidelines for the selection of the
model tuning parameters and propose a pipeline that exploits a singular value
decomposition on the raw data to make our model run efficiently on large data
sets. We demonstrate the performance of the model in a simulation study and
conclude by discussing the results of a case study using a real-world dataset
provided by the Wellcome Trust Case Control Consortium.


title:
Exact solution of the one-dimensional Hubbard model with arbitrary
  boundary magnetic fields

abstract:
  The one-dimensional Hubbard model with arbitrary boundary magnetic fields is
solved exactly via the Bethe ansatz methods. With the coordinate Bethe ansatz
in the charge sector, the second eigenvalue problem associated with the spin
sector is constructed. It is shown that the second eigenvalue problem can be
transformed into that of the inhomogeneous XXX spin chain with arbitrary
boundary fields which can be solved via the off-diagonal Bethe ansatz method.


title:
An Iterative Geometric Mean Decomposition Algorithm for MIMO
  Communications Systems

abstract:
  This paper presents an iterative geometric mean decomposition (IGMD)
algorithm for multiple-input-multiple-output (MIMO) wireless communications. In
contrast to the existing GMD algorithms, the proposed IGMD does not require the
explicit computation of the geometric mean of positive singular values of the
channel matrix and hence is more suitable for hardware implementation. The
proposed IGMD has a regular structure and can be easily adapted to solve
problems with different dimensions. We show that the proposed IGMD is
guaranteed to converge to the perfect GMD under certain sufficient condition.
Three different constructions of the proposed algorithm are proposed and
compared through computer simulations. Numerical results show that the proposed
algorithm quickly attains comparable performance to that of the true GMD within
only a few iterations.


title: On Dual Lorentzian Homothetic Exponential Motions with One Parameter

abstract:
  In this study, the concept of dual Lorentzian homotetic exponential motions
in is discussed and their velocities, accelerations obtained. Also, some
geometric results between velocity and acceleration vectors of a point in a
spatial motion are obtained. Finally, the theorems related to acceleration and
acceleration centres is given.


title: Aspects of the ETH model of the pion-nucleon interaction

abstract:
  The ETH model of the pion-nucleon ($\pi N$) interaction contains $t$-channel
$\sigma$- and $\rho$-exchange graphs, as well as the $s$- and $u$-channel
contributions with the well-established $s$ and $p$ baryon states with masses
below $2$ GeV as virtual particles; the model amplitudes obey crossing symmetry
and isospin invariance. In the present work, we give the analytical expressions
for the model contributions to the $K$-matrix elements up to (and including)
the $f$ waves. We also extract a new phase-shift solution after performing a
partial-wave analysis of meson-factory $\pi^\pm p$ elastic-scattering data
below $100$ MeV; included in our results now are also the effects of the
variation of the $\sigma$-meson mass in the interval which is currently
recommended by the Particle-Data Group. Finally, we revisit the subject of the
$\pi N$ $\Sigma$ term and, using the model amplitudes, obtain $\Sigma = 72.4
\pm 3.1$ MeV. Our prediction agrees well with the result extracted with
Olsson's method, after a few flaws in his paper [Phys. Lett. B 482 (2000) 50]
were corrected.


title:
The periodic table of topological insulators and superconductors: the
  loop sequence approach

abstract:
  In this work, a complete homotopic interpretation on the periodic table of
topological insulators and superconductors has been derived by establishing the
loop sequence of the corresponding classifying spaces. In our approach, each
classifying spaces has been regarded as a fiber bundle defined on one point,
following that the loop relationship between the classifying spaces in the same
symmetric class has been built and proved. Meanwhile, the loop sequence between
the classifying spaces with the same spatial dimension has also been developed
based on the minimal geodesic approximation. Finally, by building the loop
sequence for general dimensions and symmetric classes, a complete homotopic
understanding about the whole periodic table of any classifying spaces is
achieved. Our approach provides a unified way to interpret the topological
relationship between any free-fermion systems.


title:
Reconstructing Einstein-Aether Gravity from Ordinary and
  Entropy-Corrected Holographic and New Agegraphic Dark Energy Models

abstract:
  Here we briefly discuss the Einstein-Aether gravity theory by modification of
Einstein-Hilbert action. We find the modified Friedmann equations and then from
the equations we find the effective density and pressure for Einstein-Aether
gravity sector. These can be treated as dark energy provided some restrictions
on the free function $F(K)$, where $K$ is proportional to $H^{2}$. Assuming two
types of the power law solutions of the scale factor, we have reconstructed the
unknown function $F(K)$ from HDE and NADE and their entropy-corrected versions
(ECHDE and ECNADE). We also obtain the EoS parameter for Einstein-Aether
gravity dark energy. For HDE and NADE, we have shown that the type I scale
factor generates the quintessence scenario only and type II scale factor
generates phantom scenario. But for ECHDE and ECNADE, the both types of scale
factors can accommodate the transition from quintessence to phantom stages
i.e., phantom crossing is possible for entropy corrected terms of HDE and NADE
models. Finally, we show that the models are classically unstable.


title: Modeling Vanilla Option prices: A simulation study by an implicit method

abstract:
  Option contracts can be valued by using the Black-Scholes equation, a partial
differential equation with initial conditions. An exact solution for European
style options is known. The computation time and the error need to be minimized
simultaneously. In this paper, the authors have solved the Black-Scholes
equation by employing a reasonably accurate implicit method. Options with known
analytic solutions have been evaluated. Furthermore, an overall second order
accurate space and time discretization is proposed in this paper Keywords:
Computational finance, implicit methods, finite differences, call/put options.


title:
The role of $N^*(2120)$ nucleon resonance in $K\Lambda(1520)$ photon and
  hadronic productions

abstract:
  The associate $K\Lambda(1520)$ photon and hadronic production in the $\gamma
p \to K^+\Lambda(1520)$, $p p \to p K^+ \Lambda(1520)$ and $\pi^- p \to K^0
\Lambda(1520)$ reactions are investigated within the effective Lagrangian
approach and the isobar model. We are interested in the contribution from the
$N^*(2120)$ (previously called $N^*(2080)$) resonance, which has a significant
coupling to the $K\Lambda(1520)$ channel. The theoretical results show that the
current experimental data for the $\gamma p \to K^+\Lambda(1520)$ reaction
favor the existence of the $N^*(2120)$ resonance, and that these measurements
can be used to further constrain its properties. We present results, including
the $N^*(2120)$ contribution, for total cross sections of the $\gamma p \to
K^+\Lambda(1520)$, $\pi^- p \to K^0 \Lambda(1520)$, and $p p \to p K^+
\Lambda(1520)$ reactions. For this latter one, we also calculate invariant mass
and Dalitz plot distributions.


title: An acoustic wave equation based on viscoelasticity

abstract:
  An acoustic wave equation for pressure accounting for viscoelastic
attenuation is derived from viscoelastic equations of motion. It is assumed
that the relaxation moduli are completely monotonic. The acoustic equation
differs significantly from the equations proposed by Szabo (1994) and in
several other papers. Integral representations of dispersion and attenuation
are derived. General properties and asymptotic behavior of attenuation and
dispersion in the low and high frequency range are studied. The results are
compatible with experiments. The relation between the asymptotic properties of
attenuation and wavefront singularities is examined. The theory is applied to
some classes of viscoelastic models and to the quasi-linear attenuation
reported in seismology.


title: Magneto--optical matter wave Bragg diffraction

abstract:
  We have performed a principle-proof-experiment of a magneto-optical
diffraction (MOD) technique that requires no energy level splitting by
homogeneous magnetic field and a circularly polarized optical lattice, avoiding
system errors in an interferometer based on the MOD. The principle for this new
MOD is that asynchronized switching of quadrupole trap and Ioffe trap in a
quadrupole-Ioffe-configuration trap can generate a residual magnetic force to
drive a Bose-Einstein condensate (BEC) to move. We have observed asymmetric
atomic diffraction resulting from the asymmetric distribution of the Bloch
eigenstates involved in the diffraction process when the condensate is driven
by such a force, and matter-wave self-imaging due to coherent population
oscillation of the dominantly occupied Bloch eigenstates. We have classified
the mechanisms that lead to symmetric or asymmetric diffraction, and found that
our experiment presents a magnetic alternative to a moving optical lattice,
with a great potential to achieve a very large momentum transfer ($>110 \hbar
k$) to a BEC using well-developed magnetic trapping techniques.


title:
Extremal properties of tropical eigenvalues and solutions to tropical
  optimization problems

abstract:
  An unconstrained optimization problem is formulated in terms of tropical
mathematics to minimize a functional that is defined on a vector set by a
matrix and calculated through multiplicative conjugate transposition. For some
particular cases, the minimum in the problem is known to be equal to the
tropical spectral radius of the matrix. We examine the problem in the common
setting of a general idempotent semifield. A complete direct solution in a
compact vector form is obtained to this problem under fairly general
conditions. The result is extended to solve new tropical optimization problems
with more general objective functions and inequality constraints. Applications
to real-world problems that arise in project scheduling are presented. To
illustrate the results obtained, numerical examples are also provided.


title: Unitary evolution as a uniqueness criterion

abstract:
  We briefly review the use of unitary evolution as a uniqueness criterion in
the selection of quantum representations, in the context of scalar fields in
non-stationary situations.


title: Vector Fields on certain quotients of complex Stiefel manifolds

abstract:
  We consider quotients of complex Stiefel manifolds by finite cyclic groups
whose action is induced by the scalar multiplication on the corresponding
complex vector space. We obtain a description of their tangent bundles, compute
their mod p cohomology and obtain estimates for their span (with respect to
their standard differentiable structure). We compute the Pontrjagin and
Stiefel-Whitney classes of these manifolds and give applications to their
stable parallelizability.


title:
On Fast Implementation of Clenshaw-Curtis and Fej\'{e}r-type Quadrature
  Rules

abstract:
  Based upon the fast computation of the coefficients of the interpolation
polynomials at Chebyshev-type points by FFT, DCT and IDST, respectively,
together with the efficient evaluation of the modified moments by forwards
recursions or by the Oliver's algorithm, this paper presents interpolating
integration algorithms, by using the coefficients and modified moments, for
Clenshaw-Curtis, Fej\'er's first and second-type rules for Jacobi or Jacobi
weights multiplied by a logarithmic function. The corresponding {\sc Matlab}
codes are included. Numerical examples illustrate the stability, accuracy of
the Clenshaw-Curtis, Fej\'{e}r's first and second rules, and show that the
three quadratures have nearly the same convergence rates as Gauss-Jacobi
quadrature for functions of finite regularities for Jacobi weights, and are
more efficient upon the cpu time than the Gauss evaluated by fast computation
of the weights and nodes by {\sc Chebfun}.


title: Thermodynamic Treatment of High Energy Heavy Ion Collision

abstract:
  The hadron production in heavy ion collision is treated in the framework of
thermodynamic vision. Thermodynamic system formed during central collision of
Pb-Pb at high energies is considered, through which binary collision is assumed
among the valance quarks. The partition function of the system is calculated;
accordingly the free available energy, the entropy and the chemical potential
are calculated. The concept of string fragmentation and defragmentation are
used to form the newly produced particles. The average multiplicity of the
newly produced particles are calculated and compared with the recent
experimental results.


title: Vector fields on right generalized complex projective Stiefel manifolds

abstract:
  The question of paralleizability and stable parallelizability of a family of
manifolds obtained as a quotients of circle action on the complex Stiefel
manifolds are studied and settled.


title: Quantum phases of a one-dimensional dipolar Fermi gas

abstract:
  We quantitatively obtain the quantum ground-state phases of a Fermi system
with on-site and dipole-dipole interactions in one-dimensional lattice chains
within the density matrix renormalization group. We show, at a given spin
polarization, the existence of six phases in the phase diagram and find that
the phases are highly dependent on the spin degree of freedom. These phases can
be constructed using available experimental techniques.


title: Spacetime Singularities

abstract:
  We present here an overview of our basic understanding and recent
developments on spacetime singularities in the Einstein theory of gravity.
Several issues related to physical significance and implications of
singularities are discussed. The nature and existence of singularities are
considered which indicate the formation of super ultra-dense regions in the
universe as predicted by the general theory of relativity. Such singularities
develop during the gravitational collapse of massive stars and in cosmology at
the origin of the universe. Possible astrophysical implications of the
occurrence of singularities in the spacetime universe are indicated. We discuss
in some detail the profound and key fundamental issues that the singularities
give rise to, such as the cosmic censorship and predictability in the universe,
naked singularities in gravitational collapse and their relevance in black hole
physics today, and their astrophysical implications in modern relativistic
astrophysics and cosmology.


title: Symmetries of 2+1-dimensional variable coefficient Burgers equations

abstract:
  We consider a class of variable coefficient Burgers equations in 2+1
dimensions and make use of their equivalence group to give a complete symmetry
classification up to equivalence. Equivalence group is also applied to pick out
the most general equation transformable to its constant coefficient form. The
infinite-dimensional symmetry is used to transform the equation to a
one-dimensional one.


title: Shadowing property, weak mixing and regular recurrence

abstract:
  We show that a non-wandering dynamical system with the shadowing property is
either equicontinuous or has positive entropy and that in this context
uniformly positive entropy is equivalent to weak mixing. We also show that weak
mixing together with the shadowing property imply the specification property
with a special kind of regularity in tracing (a weaker version of periodic
specification property). This in turn implies that the set of ergodic measures
supported on the closures of orbits of regularly recurrent points is dense in
the space of all invariant measures (in particular, invariant measures in such
a system form the Poulsen simplex, up to an affine homeomorphism).


title: Covering Paths and Trees for Planar Grids

abstract:
  Given a set of points in the plane, a covering path is a polygonal path that
visits all the points. In this paper we consider covering paths of the vertices
of an n x m grid. We show that the minimal number of segments of such a path is
$2\min(n,m)-1$ except when we allow crossings and $n=m\ge 3$, in which case the
minimal number of segments of such a path is $2\min(n,m)-2$, i.e., in this case
we can save one segment. In fact we show that these are true even if we
consider covering trees instead of paths.
  These results extend previous works on axis-aligned covering paths of n x m
grids and complement the recent study of covering paths for points in general
position, in which case the problem becomes significantly harder and is still
open.


title: Square Function Estimates and Functional Calculi

abstract:
  In this paper the notion of an abstract square function (estimate) is
introduced as an operator X to gamma (H; Y), where X, Y are Banach spaces, H is
a Hilbert space, and gamma(H; Y) is the space of gamma-radonifying operators.
By the seminal work of Kalton and Weis, this definition is a coherent
generalisation of the classical notion of square function appearing in the
theory of singular integrals. Given an abstract functional calculus (E, F, Phi)
on a Banach space X, where F (O) is an algebra of scalar-valued functions on a
set O, we define a square function Phi_gamma(f) for certain H-valued functions
f on O. The assignment f to Phi_gamma(f) then becomes a vectorial functional
calculus, and a "square function estimate" for f simply means the boundedness
of Phi_gamma(f). In this view, all results linking square function estimates
with the boundedness of a certain (usually the H-infinity) functional calculus
simply assert that certain square function estimates imply other square
function estimates. In the present paper several results of this type are
proved in an abstract setting, based on the principles of subordination,
integral representation, and a new boundedness concept for subsets of Hilbert
spaces, the so-called ell-1 -frame-boundedness. These abstract results are then
applied to the H-infinity calculus for sectorial and strip type operators. For
example, it is proved that any strip type operator with bounded scalar
H-infinity calculus on a strip over a Banach space with finite cotype has a
bounded vectorial H-infinity calculus on every larger strip.


title: Convex and starshaped sets in manifolds without conjugate points

abstract:
  Let $\mathcal{W}^{n}$ be the class of $C^{\infty }$ complete simply connected
$n-$dimensional manifolds without conjugate points. The hyperbolic space as
well as Euclidean space are good examples of such manifolds. Let $% W\in
\mathcal{W}^{n}$ and let $A$ be a subset of $W$. This article aims at
characterization and building convex and starshaped sets in this class from
inside. For example, it is proven that, for a compact starshaped set, the
convex kernel is the intersection of stars of extreme points only. Also, if a
closed unbounded convex set $A$ does not contain a totally geodesic
hypersurface and its boundary has no geodesic ray, then $A$ is the convex hull
of its extreme points. This result is a refinement of the well-known
Karein-Millman theorem.


title: Geodesic continued fractions and LLL

abstract:
  We discuss a proposal for a continued fraction-like algorithm to determine
simultaneous rational approximations to $d$ real numbers
$\alpha_1,\ldots,\alpha_d$. It combines an algorithm of Hermite and Lagarias
with ideas from LLL-reduction. We dynamically LLL-reduce a quadratic form with
parameter $t$ as $t\downarrow0$. The new idea in this paper is that checking
the LLL-conditions consists of solving linear equations in $t$.


title: In-Band Full-Duplex Wireless: Challenges and Opportunities

abstract:
  In-band full-duplex (IBFD) operation has emerged as an attractive solution
for increasing the throughput of wireless communication systems and networks.
With IBFD, a wireless terminal is allowed to transmit and receive
simultaneously in the same frequency band. This tutorial paper reviews the main
concepts of IBFD wireless. Because one the biggest practical impediments to
IBFD operation is the presence of self-interference, i.e., the interference
caused by an IBFD node's own transmissions to its desired receptions, this
tutorial surveys a wide range of IBFD self-interference mitigation techniques.
Also discussed are numerous other research challenges and opportunities in the
design and analysis of IBFD wireless systems.


title: s-wave pairing in the optimally-doped LaO0.5F0.5BiS2 superconductor

abstract:
  We report on the magnetic and superconducting properties of LaO0.5F0.5BiS2 by
means of zero- (ZF) and transverse-field (TF) muon-spin spectroscopy
measurements (uSR). Contrary to previous results on iron-based superconductors,
measurements in zero field demonstrate the absence of magnetically ordered
phases. TF-uSR data give access to the superfluid density, which shows a marked
2D character with a dominant s-wave temperature behavior. The field dependence
of the magnetic penetration depth confirms this finding and further suggests
the presence of an anisotropic superconducting gap.


title: Two-electron state from the Floquet scattering matrix perspective

abstract:
  Two single-particle sources coupled in series to a chiral electronic
waveguide can serve as a probabilistic source of two-particle excitations with
tunable properties. The second-order correlation function, characterizing the
state of emitted electrons in space-time, is expressed in terms of the Floquet
scattering matrix of a source. It is shown that the Fourier transform of the
correlation function, characterizing the emitted state in energy space, can be
accessed with the help of an energy resolved shot-noise measurement. The
two-electron state emitted adiabatically is discussed in detail. In particular,
the two-electron wave function is represented via two different sets of
single-particle wave functions accessible experimentally.


title:
A Lossy Graph Model for Decoding Delay Reduction in Instantly Decodable
  Network Coding

abstract:
  In this paper, we study the broadcast decoding delay performance of
generalized instantly decodable network coding (G-IDNC) in the lossy feedback
scenario. The problem is formulated as a maximum weight clique problem over the
G-IDNC graph in [1]. In order to further minimize the decoding delay, we
introduce in this paper the lossy G-IDNC graph (LG-IDNC). Whereas the G-IDNC
graph represents only doubtless combinable packets, the LG-IDNC graph
represents also uncertain packet combinations when the expected decoding delay
of the encoded packet is lower than the individual expected decoding delay of
each packet encoded in it. Since the maximum weight clique problem is known to
be NP-hard, we use the heuristic introduced in [2] to discover the maximum
weight clique in the LG-IDNC graph and finally we compare the decoding delay
performance of LG-IDNC and G-IDNC graphs through extensive simulations.
Numerical results show that our new LG-IDNC graph formulation outperforms the
G-IDNC graph formulation in all situations and achieves significant improvement
in the decoding delay especially when the feedback erasure probability is
higher than the packet erasure probability.


title:
An Adaptive Amoeba Algorithm for Shortest Path Tree Computation in
  Dynamic Graphs

abstract:
  This paper presents an adaptive amoeba algorithm to address the shortest path
tree (SPT) problem in dynamic graphs. In dynamic graphs, the edge weight
updates consists of three categories: edge weight increases, edge weight
decreases, the mixture of them. Existing work on this problem solve this issue
through analyzing the nodes influenced by the edge weight updates and recompute
these affected vertices. However, when the network becomes big, the process
will become complex. The proposed method can overcome the disadvantages of the
existing approaches. The most important feature of this algorithm is its
adaptivity. When the edge weight changes, the proposed algorithm can recognize
the affected vertices and reconstruct them spontaneously. To evaluate the
proposed adaptive amoeba algorithm, we compare it with the Label Setting
algorithm and Bellman-Ford algorithm. The comparison results demonstrate the
effectiveness of the proposed method.


title: An asymptotic formula in q for the number of [n,k] q-ary MDS codes

abstract:
  We obtain an asymptotic formula in q for the number of MDS codes of length n
and dimension k over a finite field with q elements.


title: Ferrimagnetos de Ising con Diluci\'on

abstract:
  We perform numerical studies of a three dimensional Ising mixed model at
different concentrations of quenched non magnetic impurities. Our preliminary
results indicate that both, the compensation temperature and the temperature
that signal the transition from an ordered to a disordered phase, decrease
linearly with the concentration of impurities, for concentrations below 30%.
For percentages of impurities above 30% the compensation temperature
disappears.


title: Functional Factorial K-means Analysis

abstract:
  A new procedure for simultaneously finding the optimal cluster structure of
multivariate functional objects and finding the subspace to represent the
cluster structure is presented. The method is based on the $k$-means criterion
for projected functional objects on a subspace in which a cluster structure
exists. An efficient alternating least-squares algorithm is described, and the
proposed method is extended to a regularized method for smoothness of weight
functions. To deal with the negative effect of the correlation of coefficient
matrix of the basis function expansion in the proposed algorithm, a two-step
approach to the proposed method is also described. Analyses of artificial and
real data demonstrate that the proposed method gives correct and interpretable
results compared with existing methods, the functional principal component
$k$-means (FPCK) method and tandem clustering approach. It is also shown that
the proposed method can be considered complementary to FPCK.


title:
Optimal Binary Subspace Codes of Length 6, Constant Dimension 3 and
  Minimum Distance 4

abstract:
  It is shown that the maximum size of a binary subspace code of packet length
$v=6$, minimum subspace distance $d=4$, and constant dimension $k=3$ is $M=77$;
in Finite Geometry terms, the maximum number of planes in
$\operatorname{PG}(5,2)$ mutually intersecting in at most a point is $77$.
Optimal binary $(v,M,d;k)=(6,77,4;3)$ subspace codes are classified into $5$
isomorphism types, and a computer-free construction of one isomorphism type is
provided. The construction uses both geometry and finite fields theory and
generalizes to any $q$, yielding a new family of $q$-ary
$(6,q^6+2q^2+2q+1,4;3)$ subspace codes.


title:
Dependencia de la Temperatura de Compensaci\'on en Modelos de Multicapas
  Ferrimagn\'eticas de tipo $3(S_{1-x} \sigma_x)/\sigma$

abstract:
  We investigate numerically the behavior of the compensation temperature,
$T_{comp}$, in ferrimagnetic multilayer in the type $3(S_{1-x}
\sigma_x)/\sigma$ with respect to the increase of the spin concentration
$\sigma_x$, which are randomly distributive in a mix of spins $S = 0, \pm 1$
and $\sigma = \pm 1/2$, with ferromagnetic interaction between spins of the
same type, and antiferromagnetic interaction for spins of different type. We
have found that $T_{comp}$ decrease slowly with the increase of $x$, until
$\sigma_x$ represent a little more than 40\% of the spin mixture. For higher
concentration values $T_{comp}$ drops abruptly and disappears, as predicted by
experimental result.


title: Thompson Sampling for Complex Bandit Problems

abstract:
  We consider stochastic multi-armed bandit problems with complex actions over
a set of basic arms, where the decision maker plays a complex action rather
than a basic arm in each round. The reward of the complex action is some
function of the basic arms' rewards, and the feedback observed may not
necessarily be the reward per-arm. For instance, when the complex actions are
subsets of the arms, we may only observe the maximum reward over the chosen
subset. Thus, feedback across complex actions may be coupled due to the nature
of the reward function. We prove a frequentist regret bound for Thompson
sampling in a very general setting involving parameter, action and observation
spaces and a likelihood function over them. The bound holds for
discretely-supported priors over the parameter space and without additional
structural properties such as closed-form posteriors, conjugate prior structure
or independence across arms. The regret bound scales logarithmically with time
but, more importantly, with an improved constant that non-trivially captures
the coupling across complex actions due to the structure of the rewards. As
applications, we derive improved regret bounds for classes of complex bandit
problems involving selecting subsets of arms, including the first nontrivial
regret bounds for nonlinear MAX reward feedback from subsets.


title:
A First Experimental Limit on In-matter Torsion from Neutron Spin
  Rotation in Liquid He-4

abstract:
  We report the first experimental upper bound to our knowledge on possible
in-matter torsion interactions of the neutron from a recent search for parity
violation in neutron spin rotation in liquid He-4. Our experiment constrains a
coefficient $\zeta$ consisting of a linear combination of parameters involving
the time components of the torsion fields $T^\mu$ and $A^\mu$ from the nucleons
and electrons in helium which violates parity. We report an upper bound of
$|\zeta|<9.1x10^{-23}$ GeV at 68% confidence level and indicate other physical
processes that could be analyzed to constrain in-matter torsion.


title: Thompson Sampling for Online Learning with Linear Experts

abstract:
  In this note, we present a version of the Thompson sampling algorithm for the
problem of online linear generalization with full information (i.e., the
experts setting), studied by Kalai and Vempala, 2005. The algorithm uses a
Gaussian prior and time-varying Gaussian likelihoods, and we show that it
essentially reduces to Kalai and Vempala's Follow-the-Perturbed-Leader
strategy, with exponentially distributed noise replaced by Gaussian noise. This
implies sqrt(T) regret bounds for Thompson sampling (with time-varying
likelihood) for online learning with full information.


title: On a development of the phenomenological renormalization group

abstract:
  We propose a modification of the Nightingale renormalization group for
lattice spin and gauge models by combining it with the cluster decimation
approximation. Essential ingredients of our approach are: 1) exact calculation
of the partition and correlation function on a finite lattice strip; 2)
preservation of the mass gap or the second moment correlation length, computed
in the infinite strip length limit, on each decimation step. The method is
applied for studying general two and three dimensional Z(N) models. A perfect
agreement with exact results (whenever available) is found. An extension of the
method to models with a continuous symmetry is briefly discussed.


title:
Deterministic polarization entanglement purification using time-bin
  entanglement

abstract:
  We present a deterministic entanglement purification protocol (EPP) working
for currently available experiment technique. In this protocol, we resort to
the robust time-bin entanglement to purify the polarization entanglement
determinately, which is quite different from the previous EPPs. After
purification, one can obtain a completely pure maximally entangled pair with
the success probability of 100%, in principle. As the maximal polarization
entanglement is of vice importance in long-distance quantum communication, this
protocol may have a wide application.


title: Phase transitions in the three-dimensional Z(N) models

abstract:
  Phase transitions in zero-temperature 3D Z(N) lattice gauge theories are
studied. We use a cluster algorithm defined for the dual formulation of the
models. We also attempt to explain the nature of the intermediate continuously
symmetric phase, which appears for N>5. The critical indices are calculated.
The results obtained are used to study the scaling of critical points with N,
as well as the scaling of finite-temperature critical points with the lattice
size in the time direction, $N_t$.


title: Superconformal Inflationary $\alpha$-Attractors

abstract:
  Recently a broad class of superconformal inflationary models was found
leading to a universal observational prediction $n_s=1-2/N$ and $r=12/N^2$.
Here we generalize this class of models by introducing a parameter $\alpha$
inversely proportional to the curvature of the inflaton Kahler manifold. In the
small curvature (large $\alpha$) limit, the observational predictions of this
class of models coincide with the predictions of generic chaotic inflation
models. However, for sufficiently large curvature (small $\alpha$), the
predictions converge to the universal attractor regime with $n_s=1-2/N$ and
$r=12\alpha/N^2$, which corresponds to the part of the $n_s-r$ plane favored by
the Planck data.


title:
The chiral phase transition for two-flavour QCD at imaginary and zero
  chemical potential

abstract:
  The chiral symmetry of QCD with two massless quark flavours gets restored in
a non-analytic chiral phase transition at finite temperature and zero density.
Whether this is a first-order or a second-order transition has not yet been
determined unambiguously, due to the difficulties of simulating light quarks.
We investigate the nature of the chiral transition as a function of quark mass
and imaginary chemical potential, using staggered fermions on N_t=4 lattices.
At sufficiently large imaginary chemical potential, a clear signal for a
first-order transition is obtained for small masses, which weakens with
decreasing imaginary chemical potential. The second-order critical line
m_c(mu_i), which marks the boundary between first-order and crossover
behaviour, extrapolates to a finite m_c(mu_i=0) with known critical exponents.
This implies a definitely first-order transition in the chiral limit on
relatively coarse, N_t=4 lattices.


title: Defect-induced conductivity anisotropy in MoS2 monolayers

abstract:
  Various types of defects in MoS2 monolayers and their influence on the
electronic structure and transport properties have been studied using the
Density-Functional based Tight-Binding method in conjunction with the Green's
Function approach. Intrinsic defects in MoS2 monolayers significantly affect
their electronic properties. Even at low concentration they considerably alter
the quantum conductance. While the electron transport is practically isotropic
in pristine MoS2, strong anisotropy is observed in the presence of defects.
Localized mid-gap states are observed in semiconducting MoS2 that do not
contribute to the conductivity but direction-dependent scatter the current, and
that the conductivity is strongly reduced across line defects and selected
grain boundary models.


title: Majority out-dominating functions in digraphs

abstract:
  At least two different notions have been published under the name "majority
domination in graphs": Majority dominating functions and majority dominating
sets. In this work we extend the former concept to digraphs. Given a digraph
$D=(V,A),$ a function $f : V \rightarrow \{-1,1\}$ such that $f(N^+[v])\geq1$
for at least half of the vertices $v$ in $V$ is a majority out-dominating
function (MODF) of $D.$ The weight of a MODF $f$ is $w(f)=\sum\limits_{v\in
V}f(v),$ and the minimum weight of a MODF in $D$ is the majority out-domination
number of $D,$ denoted $\gamma^+_{maj}(D).$ In this work we introduce these
concepts and prove some results regarding them, among which the fact that the
decision problem of finding a majority out-dominating function of a given
weight is NP-complete.


title:
A selection theorem for set-valued maps into normally supercompact
  spaces

abstract:
  The following selection theorem is established:\\ Let $X$ be a compactum
possessing a binary normal subbase $\mathcal S$ for its closed subsets. Then
every set-valued $\mathcal S$-continuous map $\Phi\colon Z\to X$ with closed
$\mathcal S$-convex values, where $Z$ is an arbitrary space, has a continuous
single-valued selection. More generally, if $A\subset Z$ is closed and any map
from $A$ to $X$ is continuously extendable to a map from $Z$ to $X$, then every
selection for $\Phi|A$ can be extended to a selection for $\Phi$.
  This theorem implies that if $X$ is a $\kappa$-metrizable (resp.,
$\kappa$-metrizable and connected) compactum with a normal binary closed
subbase $\mathcal S$, then every open $\mathcal S$-convex surjection $f\colon
X\to Y$ is a zero-soft (resp., soft) map. Our results provide some
generalizations and specifications of Ivanov's results (see \cite{i1},
\cite{i2}, \cite{i3}) concerning superextensions of $\kappa$-metrizable
compacta.


title: Lattice Effective Field Theory for Medium-Mass Nuclei

abstract:
  We extend Nuclear Lattice Effective Field Theory (NLEFT) to medium-mass
nuclei, and present results for the ground states of alpha nuclei from $^4$He
to $^{28}$Si, calculated up to next-to-next-to-leading order (NNLO) in the EFT
expansion. This computational advance is made possible by extrapolations of
lattice data using multiple initial and final states. For our soft two-nucleon
interaction, we find that the overall contribution from multi-nucleon forces
must change sign from attractive to repulsive with increasing nucleon number.
This effect is not produced by three-nucleon forces at NNLO, but it can be
approximated by an effective four-nucleon interaction. We discuss the
convergence of the EFT expansion and the broad significance of our findings for
future ab initio calculations.


title: FACT - Long-term Monitoring of Bright TeV-Blazars

abstract:
  Since October 2011, the First G-APD Cherenkov Telescope (FACT) is operated
successfully on the Canary Island of La Palma. Apart from the proof of
principle for the use of G-APDs in Cherenkov telescopes, the major goal of the
project is the dedicated long-term monitoring of a small sample of bright TeV
blazars. The unique properties of G-APDs permit stable observations also during
strong moon light. Thus a superior sampling density is provided on time scales
at which the blazar variability amplitudes are expected to be largest, as
exemplified by the spectacular variations of Mrk 501 observed in June 2012.
While still in commissioning, FACT monitored bright blazars like Mrk 421 and
Mrk 501 during the past 1.5 years so far. Preliminary results including the Mrk
501 flare from June 2012 will be presented.


title: Majority out-dominating sets in digraphs

abstract:
  The concept of majority domination in graphs has been defined in at least two
different ways: As a function and as a set. In this work we extend the latter
concept to digraphs, while the former was extended in another paper. Given a
digraph $D=(V,A),$ a set $S\subseteq V$ is a \textit{majority out-dominating
set} (MODS) of $D$ if $|N^+[S]|\geq \frac {n}{2}.$ The minimum cardinality of a
MODS in $D$ is the {\it set majority out-domination number} $\gamma^+_{m}(D)$
of $D.$ In this work we introduce these concepts and prove some results about
them, among which the characterization of minimal MODSs.


title:
Kusuoka-Stroock gradient bounds for the solution of the filtering
  equation

abstract:
  We obtain sharp gradient bounds for perturbed diffusion semigroups. In
contrast with existing results, the perturbation is here random and the bounds
obtained are pathwise. Our approach builds on the classical work of Kusuoka and
Stroock [7],[9],[10],[11], and extends their program developed for the heat
semi-group to solutions of stochastic partial differential equations. The work
is motivated by and applied to nonlinear filtering. The analysis allows us to
derive pathwise gradient bounds for the un-normalised conditional distribution
of a partially observed signal. It uses a pathwise representation of the
perturbed semigroup in the spirit of classical work by Ocone [14]. The
estimates we derive have sharp small time asymptotics.


title: Bargmann-Fock realization of the noncommutative torus

abstract:
  We give an interpretation of the Bargman transform as a correspondence
between state spaces that is analogous to commonly considered intertwiners in
representation theory of finite groups. We observe that the non-commutative
torus is nothing else that the range of the star-exponential for the Heisenberg
group within the Kirillov's orbit method context. We deduce from this a
realization of the non-commutative torus as acting on a Fock space of entire
functions.


title:
Magnetic fields in single late-type giants in the Solar vicinity: How
  common is magnetic activity on the giant branches?

abstract:
  We present our first results on a new sample containing all single G,K and M
giants down to V = 4 mag in the Solar vicinity, suitable for
spectropolarimetric (Stokes V) observations with Narval at TBL, France. For
detection and measurement of the magnetic field (MF), the Least Squares
Deconvolution (LSD) method was applied (Donati et al. 1997) that in the present
case enables detection of large-scale MFs even weaker than the solar one (the
typical precision of our longitudinal MF measurements is 0.1-0.2 G). The
evolutionary status of the stars is determined on the basis of the evolutionary
models with rotation (Lagarde et al. 2012; Charbonnel et al., in prep.) and
fundamental parameters given by Massarotti et al. (1998). The stars appear to
be in the mass range 1-4 M_sun, situated at different evolutionary stages after
the Main Sequence (MS), up to the Asymptotic Giant Branch (AGB). The sample
contains 45 stars. Up to now, 29 stars are observed (that is about 64 % of the
sample), each observed at least twice. For 2 stars in the Hertzsprung gap, one
is definitely Zeeman detected. Only 5 G and K giants, situated mainly at the
base of the Red Giant Branch (RGB) and in the He-burning phase are detected.
Surprisingly, a lot of stars ascending towards the RGB tip and in early AGB
phase are detected (8 of 13 observed stars). For all Zeeman detected stars v
sin i is redetermined and appears in the interval 2-3 km/s, but few giants with
MF possess larger v sin i.


title:
Flexible Parametrization of Generalized Parton Distributions: The
  Chiral-Odd Sector

abstract:
  We present a physically motivated parameterization of the chiral-odd
generalized parton distributions. The parametrization is an extension of our
previous one in the chiral-even sector which was based on the reggeized diquark
model. While for chiral even generalized distributions a quantitative fit with
uncertainty estimation can be performed using deep inelastic scattering data,
nucleon electromagnetic, axial and pseudoscalar form factors measurements, and
all available deeply virtual Compton scattering data, the chiral-odd sector is
far less constrained. While awaiting the analysis of measurements on
pseudoscalar mesons exclusive electroproduction which are key for the
extraction of chiral odd GPDs, we worked out a connection between the
chiral-even and chiral-odd reduced helicity amplitudes using Parity
transformations. The connection works for a class of models including
two-components models. This relation allows us to estimate the size of the
various chiral odd contributions and it opens the way for future quantitative
fits.


title: Deterministic Parameterized Algorithms for Matching and Packing Problems

abstract:
  We present three deterministic parameterized algorithms for well-studied
packing and matching problems, namely, Weighted q-Dimensional p-Matching
((q,p)-WDM) and Weighted q-Set p-Packing ((q,p)-WSP). More specifically, we
present an O*(2.85043^{(q-1)p}) time deterministic algorithm for (q,p)-WDM, an
O*(8.04143^p) time deterministic algorithm for the unweighted version of
(3,p)-WDM, and an O*((0.56201\cdot 2.85043^q)^p) time deterministic algorithm
for (q,p)-WSP. Our algorithms significantly improve the previously best known
O* running times in solving (q,p)-WDM and (q,p)-WSP, and the previously best
known deterministic O* running times in solving the unweighted versions of
these problems. Moreover, we present kernels of size O(e^qq(p-1)^q) for
(q,p)-WDM and (q,p)-WSP, improving the previously best known kernels of size
O(q!q(p-1)^q) for these problems.


title:
Complex and strongly anisotropic magnetism in the pure spin system
  EuRh2Si2

abstract:
  In divalent Eu systems, the 4f local moment has a pure spin state J=S=7/2.
Although the absence of orbital moment precludes crystal electric field
effects, we report a sizeable magnetic anisotropy in single crystals of
EuRh2Si2. We observed a surprisingly complex magnetic behavior with three
succesive phase transitions. The Eu2+ moments order in a likely
amplitude-modulated structure below 24.5K, undergoing a further transition to a
structure that is possibly of the equal moment type, and a first order
transition at lower temperatures, presumably into a spin spiral structure. The
sharp metamagnetic transition observed at low fields applied perpendicular to
the hard axis is consistent with a change from a spiral to a fan structure.
These magnetic structures are presumably formed by ferromagnetic planes
perpendicular to the c axis, stacked antiferromagnetically along c but not of
type I, at least just below the ordering temperature. Since EuRh2Si2 is
isoelectronic to EuFe2As2, our results are also relevant for the complex
Eu-magnetism observed there, especially for the transition from an
antiferromagnetic to a ferromagnetic state observed in EuFe2P2 upon
substituting As by P.


title:
On the optimal tradeoff of average service cost rate, average utility
  rate, and average delay for the state dependent M/M/1 queue

abstract:
  The optimal tradeoff between average service cost rate, average utility rate,
and average delay is addressed for a state dependent M/M/1 queueing model, with
controllable queue length dependent service rates and arrival rates. For a
model with a constant arrival rate $\lambda$ for all queue lengths, we obtain
an asymptotic characterization of the minimum average delay, when the average
service cost rate is a small positive quantity, $V$, more than the minimum
average service cost rate required for queue stability. We show that depending
on the value of the arrival rate $\lambda$, the assumed service cost rate
function, and the possible values of the service rates, the minimum average
delay either: a) increases only to a finite value, b) increases without bound
as $\log\frac{1}{V}$, c) increases without bound as $\frac{1}{V}$, or d)
increases without bound as $\frac{1}{\sqrt{V}}$, when $V \downarrow 0$. We then
extend our analysis to (i) a complementary problem, where the tradeoff of
average utility rate and average delay is analysed for a M/M/1 queueing model,
with controllable queue length dependent arrival rates, but a constant service
rate $\mu$ for all queue lengths, and (ii) a M/M/1 queueing model, with
controllable queue length dependent service rates and arrival rates, for which
we obtain an asymptotic characterization of the minimum average delay under
constraints on both the average service cost rate as well as the average
utility rate. The results that we obtain are useful in obtaining intuition as
well guidance for the derivation of similar asymptotic lower bounds, such as
the Berry-Gallager asymptotic lower bound, for discrete time queueing models.


title:
Constraints on the R-charges of Free Bound States from the
  R\"omelsberger Index

abstract:
  The R\"omelsberger index on S^3 x R serves as a powerful test for conjectured
dualities, relying on the claim that this object is an RG-invariant. In this
work we support this claim by showing that the singularities suggested by
Witten of "states moving in from infinity" are excluded on S^3 x R. In
addition, we provide an application of the R\"omelsberger index, in the form of
a constraint on the RG flow of supersymmetric theories. The constraint, which
applies for asymptotically free theories with unbroken supersymmetry and
non-anomalous R-symmetry, is the following: if the R-charges of the chiral
multiplets in the UV theory are 0<q_i<2 and the IR theory can be described as a
free theory of chiral bound states, then the R-charges of these bound states,
~q_j, are constrained such that 0<~q_j<2. We thus provide a proof of a weak
version of a conjecture proposed by Intriligator. We mention some applications
of this result.


title:
Periodic orbits in cosmological billiards: the Selberg trace formula for
  asymptotic Bianchi IX universes, evidence for scars in the wavefunction of
  the quantum universe and large-scale structure anisotropies of the present
  universe

abstract:
  The Selberg trace formula is specified for cosmological billiards in $4=3+1$
spacetime dimensions. The spectral formula is rewritten as an exact sum over
the initial conditions for the Einstein field equations for which periodic
orbits are implied. For this, a suitable density of measure invariant under the
billiard maps has been defined, within the statistics implied by the BKL
paradigm. The trace formula has also been specified for the stochastic limit of
the dynamics, where the sum over initial conditions has been demonstrated to be
equivalent to a sum over suitable symmetry operations on the generators of the
groups that define the billiard dynamics, and acquires different features for
the different statistical maps.
  Evidence for scars at the quantum regime is provided. The validity of the
Selberg trace formula at the classical level and in the quantum regime enforces
the validity of the semiclassical descriptions of these systems, thus offering
further elements for the comparison of quantum-gravity effects and the present
observed structure of the universe. This procedure also constitutes a new
approach in hyperbolic geometry for the application of the Selberg trace
formula for a chaotic system whose orbits are associated to precise statistical
distributions, for both billiard tables corresponding to the desymmetrized
fundamental domain and to that a a congruence subgroup of it.

categories: gr-qc astro-ph.GA hep-th math-ph math.MP


title: Critical Thickness Ratio for Buckled and Wrinkled Fruits and Vegetables

abstract:
  Fruits and vegetables are usually composed of exocarp and sarcocarp and they
take a variety of shapes when they are ripe. Buckled and wrinkled fruits and
vegetables are often observed. This work aims at establishing the geometrical
constraint for buckled and wrinkled shapes based on a mechanical model. The
mismatch of expansion rate between the exocarp and sarcocarp can produce a
compressive stress on the exocarp. We model a fruit/vegetable with exocarp and
sarcocarp as a hyperelastic layer-substrate structure subjected to uniaxial
compression. The derived bifurcation condition contains both geometrical and
material constants. However, a careful analysis on this condition leads to the
finding of a critical thickness ratio which separates the buckling and
wrinkling modes, and remarkably, which is independent of the material
stiffnesses. More specifically, it is found that if the thickness ratio is
smaller than this critical value a fruit/vegetable should be in a buckling mode
(under a sufficient stress); if a fruit/vegetable in a wrinkled shape the
thickness ratio is always larger than this critical value. To verify the
theoretical prediction, we consider four types of buckled fruits/vegetables and
four types of wrinkled fruits/vegetables with three samples in each type. The
geometrical parameters for the 24 samples are measured and it is found that
indeed all the data fall into the theoretically predicted buckling or wrinkling
domains. Some practical applications based on this critical thickness ratio are
briefly discussed.


title:
Anderson Localization for the Almost Mathieu Operator in Exponential
  Regime

abstract:
  For the almost Mathieu operator
$(H_{\lambda,\alpha,\theta}u)_n=u_{n+1}+u_{n-1}+2\lambda
\cos2\pi(\theta+n\alpha)u_n$, Avila and Jitomirskaya guess that for a.e.
$\theta$, $H_{\lambda,\alpha,\theta}$ satisfies Anderson localization if $
|\lambda| > e^{ \beta} $, and they establish this for $ |\lambda| >
e^{\frac{16}{9} \beta}$. In the present paper, we extend their result to regime
$ |\lambda| > e^{\frac{3}{2} \beta}$.


title:
Conducting and insulating LaAlO$_3$/SrTiO$_3$ interfaces: A comparative
  surface photovoltage investigation

abstract:
  Surface photovoltage (SPV) spectroscopy, which is a versatile method to
analyze the energetic distribution of electronic defect states at surfaces and
interfaces of wide-bandgap semiconductor (hetero-)structures, is applied to
comparatively investigate heterostructures made of 5-unit-cell-thick LaAlO$_3$
films grown either on TiO$_2$- or on SrO-terminated SrTiO$_3$. As shown in a
number of experimental and theoretical investigations in the past, these two
interfaces exhibit dramatically different properties with the first being
conducting and the second insulating.
  Our present SPV investigation reveals clearly distinguishable interface
defect state distributions for both configurations when interpreted within the
framework of a classical semiconductor band scheme. Furthermore, bare SrTiO$_3$
crystals with TiO$_2$ or mixed SrO/TiO$_2$ terminations show similar SPV
spectra and transients as do LaAlO$_3$-covered samples with the respective
termination of the SrTiO$_3$ substrate. This is in accordance with a number of
recent works that stress the decisive role of SrTiO$_3$ and the minor role of
LaAlO$_3$ with respect to the electronic interface properties.


title:
Magnetization distribution and orbital moment in the non-Superconducting
  Chalcogenide Compound K0.8Fe1.6Se2

abstract:
  We have used polarized and unpolarized neutron diffraction to determine the
spatial distribution of the magnetization density induced by a magnetic field
of 9 T in the tetragonal phase of K0.8Fe1.6Se2. The maximum entropy
reconstruction shows clearly that most of the magnetization is confined to the
region around the iron atoms whereas there is no significant magnetization
associated with either Se or K atoms. The distribution of magnetization around
the Fe atom is slightly nonspherical with a shape which is extended along the
[0 0 1] direction in the projection. Multipolar refinement results show that
the electrons which give rise to the paramagnetic susceptibility are confined
to the Fe atoms and their distribution suggests that they occupy 3d t2g-type
orbitals with around 66% in those of xz/yz symmetry. Detail modeling of the
magnetic form factor indicates the presence of an orbital moment to the total
paramagnetic moment of Fe2+


title: Primordial Anisotropies in Gauged Hybrid Inflation

abstract:
  We study primordial anisotropies generated in the model of gauged hybrid
inflation in which the complex waterfall field is charged under a $U(1)$ gauge
field. Primordial anisotropies are generated either actively during inflation
or from inhomogeneities modulating the surface of end of inflation during
waterfall transition. We present a consistent $\delta N$ mechanism to calculate
the anisotropic power spectrum and bispectrum. We show that the primordial
anisotropies generated at the surface of end of inflation do not depend on the
number of e-folds and therefore do not produce dangerously large anisotropies
associated with the IR modes. Furthermore, one can find the parameter space
that the anisotropies generated from the surface of end of inflation cancel the
anisotropies generated during inflation, therefore relaxing the constrains on
model parameters imposed from IR anisotropies. We also show that the gauge
field fluctuations induce a red-tilted power spectrum so the averaged power
spectrum from the gauge field can change the total power spectrum from blue to
red. Therefore, hybrid inflation, once gauged under a $U(1)$ field, can be
consistent with the cosmological observations.


title: Construction of Directed Strongly Regular Graphs Using Block Matrices

abstract:
  The concept of directed strongly regular graphs was introduced by Duval in
his paper, A Directed Graph Version of Strongly Regular Graphs. Duval also
provided several construction methods for directed strongly regular graphs. The
directed strongly regular graphs reported in this paper are obtained using a
block construction of adjacency matrices of regular tournaments and circulant
matrices. We then give some algebraic and combinatorial interpretation of these
graphs in connection with known directed strongly regular graphs and related
combinatorial structures.


title: The Ostrovsky-Vakhnenko equation by a Riemann-Hilbert approach

abstract:
  We present an inverse scattering transform approach for the equation
$u_{txx}-3u_x+3u_xu_{xx}+uu_{xxx}=0$. This equation can be viewed as the short
wave model for the Degasperis-Procesi equation or the differentiated
Ostrovsky-Vakhnenko equation. The approach is based on an associated
Riemann-Hilbert problem, which allows us to give a representation for the
classical (smooth) solution, to get the principal term of its long time
asymptotics, and also to describe loop soliton solutions.


title:
Classification of Two Dimensional Topological Crystalline
  Superconductors and Majorana Bound States at Disclinations

abstract:
  We classify discrete-rotation symmetric topological crystalline
superconductors (TCS) in two dimensions and provide the criteria for a zero
energy Majorana bound state (MBS) to be present at composite defects made from
magnetic flux, dislocations, and disclinations. In addition to the Chern number
that encodes chirality, discrete rotation symmetry further divides TCS into
distinct stable topological classes according to the rotation eigenspectrum of
Bogoliubov-de Gennes quasi-particles. Conical crystalline defects are shown to
be able to accommodate robust MBS when a certain combination of these bulk
topological invariants is non-trivial as dictated by the index theorems proved
within. The number parity of MBS is counted by a $\mathbb{Z}_2$-valued index
that solely depends on the disclination and the topological class of the TCS.
We also discuss the implications for corner-bound Majorana modes on the
boundary of topological crystalline superconductors.


title: Existence of solutions of inverted variational inequalities

abstract:
  In this paper we introduce two new generalized variational inequalities, and
we give some existence results of the solutions for these variational
inequalities involving operators belonging to a recently introduced class of
operators. We show by examples, that our results fail outside of this class.
Further, we establish a result that may be viewed as a generalization of
Minty's theorem, that is, we show that under some circumstances the set of
solutions of these variational inequalities coincide. We also show that the
operators, involved in these variational inequalities, to belong to the above
mentioned class, is essential in obtaining this result.
  As application, we show that Brouwer's fixed point theorem is an easy
consequence of our results.


title: Default Clustering in Large Pools: Large Deviations

abstract:
  We study large deviations and rare default clustering events in a dynamic
large heterogeneous portfolio of interconnected components. Defaults come as
Poisson events and the default intensities of the different components in the
system interact through the empirical default rate and via systematic effects
that are common to all components. We establish the large deviations principle
for the empirical default rate for such an interacting particle system. The
rate function is derived in an explicit form that is amenable to numerical
computations and derivation of the most likely path to failure for the system
itself. Numerical studies illustrate the theoretical findings. An understanding
of the role of the preferred paths to large default rates and the most likely
ways in which contagion and systematic risk combine to lead to large default
rates would give useful insights into how to optimally safeguard against such
events.


title: First order theory of cyclically ordered groups

abstract:
  By a result known as Rieger's theorem (1956), there is a one-to-one
correspondence, assigning to each cyclically ordered group $H$ a pair $(G,z)$
where $G$ is a totally ordered group and $z$ is an element in the center of
$G$, generating a cofinal subgroup $\langle z\rangle$ of $G$, and such that the
quotient group $G/\langle z\rangle$ is isomorphic to $H$. We first establish
that, in this correspondence, the first order theory of the cyclically ordered
group $H$ is uniquely determined by the first order theory of the pair $(G,z)$.
Then we prove that the class of cyclically ordered groups is an elementary
class and give an axiom system for it. Finally we show that, in opposition to
the fact that all theories of totally Abelian ordered groups have the same
universal part, there are uncountably many universal theories of Abelian
cyclically ordered groups. We give for each of these universal theories an
invariant, which is a pair of subgroups of the group of unimodular complex
numbers.


title: Self-linked curves and normal bundle

abstract:
  We give necessary conditions on the invariants (d,g) of a smooth, integral
curve self-linked by a complete intersection of type (a,b) in projective three
space. Similar conditions are given for s.t.c.i. curves with a multiplicity
three structure.


title: Canonical solutions of the local moment problem

abstract:
  The present paper is devoted to the {\it local moment problem}, which
consists in finding of non-decreasing functions on the real axis having given
first $2n+1, \; n\geq 0,$ power moments on the whole axis and also $2m+1$ first
power moments on a certain finite axis interval. Considering the local moment
problem as a combination of the Hausdorff and Hamburger truncated moment
problems we obtain the conditions of its solvability and describe the class of
its solutions with minimal number of growth points if the problem is solvable.


title: Skeleta in non-Archimedean and tropical geometry

abstract:
  I describe an algebro-geometric theory of skeleta, which provides a unified
setting for the study of tropical varieties, skeleta of non-Archimedean
analytic spaces, and affine manifolds with singularities. Skeleta are spaces
equipped with a structure sheaf of topological semirings, and are locally
modelled on the spectra of the same. The primary result of this paper is that
the topological space underlying a non-Archimedean analytic space may locally
be recovered from the sheaf of `pointwise valuations' of its analytic
functions.


title: Self-intersection numbers of length-equivalent curves on surfaces

abstract:
  Two free homotopy classes of closed curves in an orientable surface with
negative Euler characteristic are said to be length equivalent if for any
hyperbolic structure on the surface, the length of the geodesic in one class is
equal to the length of the geodesic in the other class. We show that there are
elements in the free group of two generators that are length equivalent and
have different self-intersection numbers as elements in the fundamental group
of the punctured torus and as elements in the pair of pants. This result
answers open questions about length equivalence classes and raises new ones.


title:
Rigidity of tilting complexes and derived equivalence for self-injective
  algebras

abstract:
  We give a proof, based on the rigidity of tilting complexes, that the class
of self-injective finite-dimensional algebras over an algebraically closed
field is closed under derived equivalence.


title:
Automated Change Detection and Reactive Clustering in Multivariate
  Streaming Data

abstract:
  Many automated systems need the capability of automatic change detection
without the given detection threshold. This paper presents an automated change
detection algorithm in streaming multivariate data. Two overlapping windows are
used to quantify the changes. While a window is used as the reference window
from which the clustering is created, the other called the current window
captures the newly incoming data points. A newly incoming data point can be
considered a change point if it is not a member of any cluster. As our
clustering-based change detector does not require detection threshold, it is an
automated detector. Based on this change detector, we propose a reactive
clustering algorithm for streaming data. Our empirical results show that, our
clustering-based change detector works well with multivariate streaming data.
The detection accuracy depends on the number of clusters in the reference
window, the window width.


title:
Specific features of electric charge screening in few-layer graphene
  films

abstract:
  We present a non-linear Thomas-Fermi theory which describes the electric
charge screening in the system including two charged substrate layers separated
by a few-layered graphene film. We show that by increasing the charge at the
interfaces, the system could be turned from the weak screening regime where the
whole film responds to the external charge, to the strong screening regime
where the external charge is screened by a surface charge distribution confined
to the bounding graphene layers. The transition from weak to strong screening
is shown to turn on relatively quickly, and it happens when the applied
external charge/external field reaches a certain crossover magnitude. The
possibilities for experimental observation of the predicted crossover are
discussed.


title: Triality in so(4,4), characteristic classes, D4 and G2 singularities

abstract:
  We recall the construction of triality automorphism of so(8) given by E.
Cartan and we give a matrix representation for the real form so(4,4). We
compute the induced results on the characteristic classes. Paralelly we study
the triality automorphism of the singularity D4 (in Arnolds classification of
smooth functions) and its miniversal deformation. The similarity with Lie
theory leads us to a definition of G2 singularity.


title: Why is Astronomy Important?

abstract:
  Astronomy and related fields are at the forefront of science and technology;
answering fundamental questions and driving innovation. Although blue-skies
research like astronomy rarely contributes directly with tangible outcomes on a
short time scale, the pursuit of this research requires cutting-edge technology
and methods that can on a longer time scale, through their broader application
make a difference. A wealth of examples show how the study of astronomy
contributes to technology, economy and society by constantly pushing for
instruments, processes and software that are beyond our current capabilities.
In this essay we outline both the tangible and intangible reasons that
astronomy is an important part of society. Although we have focused mainly on
the technology and knowledge transfer, perhaps the most important contribution
is still the fact that astronomy makes us aware of how we fit into the vast
Universe.


title:
Gaussian local unitary equivalence of $n$-mode Gaussian states and
  Gaussian transformations by local operations with classical communication

abstract:
  We derive necessary and sufficient conditions for arbitrary multi--mode (pure
or mixed) Gaussian states to be equivalent under Gaussian local unitary
operations. To do so, we introduce a standard form for Gaussian states, which
has the properties that (i) every state can be transformed into its standard
form via Gaussian local unitaries and (ii) it is unique and (iii) it can be
easily computed. Thus, two states are equivalent under Gaussian local unitaries
iff their standard form coincides. We explicitly derive the standard form for
two-- and three--mode Gaussian pure states. We then investigate transformations
between these classes by means of Gaussian local operations assisted by
classical communication. For three-mode pure states, we identify a global
property that cannot be created but only destroyed by local operations. This
implies that the highly entangled family of symmetric three--mode Gaussian
states is not sufficient to generated all three-mode Gaussian states by local
Gaussian operations.


title: Compressed matched filter for non-Gaussian noise

abstract:
  We consider estimation of a deterministic unknown parameter vector in a
linear model with non-Gaussian noise. In the Gaussian case, dimensionality
reduction via a linear matched filter provides a simple low dimensional
sufficient statistic which can be easily communicated and/or stored for future
inference. Such a statistic is usually unknown in the general non-Gaussian
case. Instead, we propose a hybrid matched filter coupled with a randomized
compressed sensing procedure, which together create a low dimensional
statistic. We also derive a complementary algorithm for robust reconstruction
given this statistic. Our recovery method is based on the fast iterative
shrinkage and thresholding algorithm which is used for outlier rejection given
the compressed data. We demonstrate the advantages of the proposed framework
using synthetic simulations.


title: Comments on Information Erasure in Black Hole

abstract:
  We analyze the Kim, Lee & Lee model of information erasure by black holes and
find contradictions with standard physical laws. We demonstrate that the
erasure model leads to arbitrarily fast information erasure; the proposed
physical interpretation of information freezing at the event horizon as
observed by an asymptotic observer is problematic; and information erasure,
whatever the process may be, near the black hole horizon leads to
contradictions with quantum mechanics if Landauer's principle is assumed. The
later part of the work demonstrates the significance of the "erasure entropy."
We show that the erasure entropy is the mutual information between two
subsystems.


title: Avoiding 5-circuits in a 2-factor of cubic graphs

abstract:
  We show that every bridgeless cubic graph $G$ on $n$ vertices other than the
Petersen graph has a 2-factor with at most $2(n-2)/15$ circuits of length $5$.
An infinite family of graphs attains this bound. We also show that $G$ has a
2-factor with at most $n/5.8\overline{3}$ odd circuits. This improves the
previously known bound of $n/5.41$ [Luko\v{t}ka, M\'a\v{c}ajov\'a, Maz\'ak,
\v{S}koviera: Small snarks with large oddness, arXiv:1212.3641 [cs.DM] ].


title: Maximal Plurifinely Plurisubharmonic functions

abstract:
  The main purpose of this paper is to introduce and study the notion of
plurifinely-maximal plurifinely plurisubharmonic functions, which extends the
notion of maximal plurisubharmonic functions on a Euclidean domain to a
plurifine domain of C^n in a natural way. Our main result is that a finite
plurifinely plurisubharmonic function u on a plurifine domain U satisfies (dd^c
u)^n=0 if and only if u is plurifinely-locally plurifinely-maximal outside some
pluripolar set. In particular, a finite plurifinely-maximal plurisubharmonic
function u satisfies (dd^c u)^n=0.


title: Affineness and chromatic homotopy theory

abstract:
  Given an algebraic stack $X$, one may compare the derived category of
quasi-coherent sheaves on $X$ with the category of dg-modules over the dg-ring
of functions on $X$. We study the analogous question in stable homotopy theory,
for derived stacks that arise via realizations of diagrams of Landweber-exact
homology theories. We identify a condition (quasi-affineness of the map to the
moduli stack of formal groups) under which the two categories are equivalent,
and study applications to topological modular forms. In particular, we provide
new examples of Galois extensions of ring spectra and vanishing results about
Tate spectra.


title: Sums of Digits in q-ary Expansions

abstract:
  Let $s_q(n)$ denote the sum of the digits of a number $n$ expressed in base
$q$. We study here the ratio $\frac{s_q(n^\alpha)}{s_q(n)}$ for various values
of $q$ and $\alpha$. In 1978, Kenneth B. Stolarsky showed that
$\lim\inf_{n\rightarrow\infty}\frac{s_2(n^2)}{s_2(n)}=0$ and that
$\lim\sup_{n\rightarrow\infty}\frac{s_2(n^2)}{s_2(n)}=\infty$ using an explicit
construction. We show that for $\alpha=2$ and $q\geq 2$, the above ratio can in
fact be any positive rational number. We also study what happens when $\alpha$
is a rational number that is not an integer, terminating the resulting
expression by using the floor function.


title:
Probing the Electromagnetic Local Density of States with a Strongly
  Mixed Electric and Magnetic Dipole Emitter

abstract:
  We identify a solid-state quantum emitter whose room-temperature radiative
decay is mediated by a nearly equal mixture of isotropic electric dipole (ED)
and magnetic dipole (MD) transitions. Using energy-momentum spectroscopy, we
experimentally show that the near-infrared $^3$T$_2{\rightarrow}^3$A$_2$
emission from divalent-nickel-doped magnesium oxide (Ni$^{2+}$:MgO) is composed
of $\sim$50% MD and $\sim$50% ED transitions. We then demonstrate that the
spontaneous emission rate of these ions near planar interfaces is determined by
the combined electric and magnetic local density of optical states (LDOS). This
electromagnetic LDOS probes the total mode density, and thus similar to thermal
emission, these unique electronic emitters effectively excite all polarizations
and orientations of the electromagnetic field.


title: Four-dimensional K\"ahler metrics admitting c-projective vector fields

abstract:
  A vector field on a K\"ahler manifold is called c-projective if its flow
preserves the J-planar curves. We give a complete local classification of
K\"ahler real 4-dimensional manifolds that admit an essential c-projective
vector field. An important technical step is a local description of
4-dimensional c-projectively equivalent metrics of arbitrary signature. As an
application of our results we prove the natural analog of the classical
Yano-Obata conjecture in the pseudo-Riemannian 4-dimensional case.


title: On the Quaternionic Curves in the Semi-Euclidean Space E_2^4

abstract:
  In this study, we try to semi-real quaternionic curves in the semi-Euclidean
space E_2^4. Firstly, we introduce algebraic properties of semi-real
quaternions. And then, we give some characterizations of semi-real quaternionic
involute-evolute curves in the semi-Euclidean space E_2^4. Lastly, we
illustrate some examples and draw their figures with Mathematica Programme.


title: A completely cofacial organic semiconductor

abstract:
  Crystals of 1,3,5-tripyrrolebenzene (TPB) contain closely packed, perfectly
cofacial stacks of benzene rings with large wavefunction overlap, making it an
interesting candidate organic semiconductor. We study TPB using a variety of
ab-initio and band-structure techniques, and find very large $\pi$ overlap in
the benzene stacks, broad bands (especially for electrons), and relatively
small binding energies for polarons of both signs, making TPB a promising
quasi-one dimensional electron-transport agent. We then explore the sources of
the unusual packing in TPB, finding that calculations of intermolecular
interactions using dispersion-corrected density functional theory provide
valuable insights into why the crystals contain perfectly cofacial
$\pi$-networks.


title:
Thickness-dependent ferromagnetic metal to paramagnetic insulator
  transition in La$_{0.6}$Sr$_{0.4}$MnO$_3$ thin films studied by x-ray
  magnetic circular dichroism

abstract:
  Metallic transition-metal oxides undergo a metal-to-insulator transition
(MIT) as the film thickness decreases across a ritical thickness of several
monolayers (MLs), but its driving mechanism remains controversial. We have
studied the thickness-dependent MIT of the ferromagnetic metal
La$_{0.6}$Sr$_{0.4}$MnO$_3$ by x-ray absorption spectroscopy and x-ray magnetic
circular dichroism. As the film thickness was decreased across the critical
thickness of the MIT (6-8 ML), a gradual decrease of the ferromagnetic signals
and a concomitant increase of paramagnetic signals were observed, while the Mn
valence abruptly decreased towards Mn$^{3+}$. These observations suggest that
the ferromagnetic phase gradually and most likely inhomogeneously turns into
the paramagnetic phase and both phases abruptly become insulating at the
critical thickness.


title: Bioinspired Associative Memory System Based on Enzymatic Cascades

abstract:
  A biomolecular system representing the first realization of associative
memory based on enzymatic reactions in vitro has been designed. The system
demonstrated "training" and "forgetting" features characteristic of memory in
biological systems, but presently realized in simple biocatalytic cascades.


title: Directed cycle double covers: structure and generation of hexagon graphs

abstract:
  Jaeger's directed cycle double cover conjecture can be formulated as a
problem of existence of special perfect matchings in a class of graphs that we
call hexagon graphs. In this work, we explore the structure of hexagon graphs.
We show that hexagon graphs are braces that can be generated from the ladder on
8 vertices using two types of McCuaig's augmentations.


title:
Modularity of Biochemical Filtering for Inducing Sigmoid Response in
  Both Inputs in an Enzymatic AND Gate

abstract:
  We report the first systematic study of designed two-input biochemical
systems as information processing gates with favorable noise-transmission
properties accomplished by modifying the gate's response from convex shape to
sigmoid in both inputs. This is realized by an added chemical "filter" process
which recycles some of the output back into one of the inputs. We study a
system involving the biocatalytic function of the enzyme horseradish
peroxidase, functioning as an AND gate. We consider modularity properties, such
as the use of three different input chromogens that, when oxidized yield
signal-detection outputs for various ranges of the primary input, hydrogen
peroxide. We also examine possible uses of different filter-effect chemicals
(reducing agents) to induce the sigmoid-response. A modeling approach is
developed and applied to our data, allowing us to describe the enzymatic
kinetics in the framework of a formulation suitable for evaluating the
noise-handling properties of the studied systems as logic gates for information
processing steps.


title: A Bayesian Residual-Based Test for Cointegration

abstract:
  Cointegration is an important concept in the analysis of non-stationary
time-series, giving conditions under which a collection of non-stationary
processes has an underlying stationary (cointegration) relationship. In this
paper we present the first fully Bayesian residual-based test for
cointegration, where we consider the whole space of possible cointegration
relationships when testing for the presence of cointegration. We first
demonstrate that such a test can be performed exactly in the case where the
residual process follows a first-order autoregressive process. We then extend
this test to include more complex residual processes, where we first consider a
suitable cointegration test-statistic and then leverage Bayesian sampling
techniques to perform the necessary inference. We empirically demonstrate that
our Bayesian approach attains a superior classification accuracy than existing
approaches, all of which use a point estimate of the cointegration relationship
in their test. Finally, we demonstrate our approach on some real world
financial time-series data.


title:
A highly-ordered, high mobility organic semiconductor grown from a
  mesophase: A test of polaron band theory

abstract:
  We find that the hole mobility of the crystal smectic phases of the liquid
crystal 1,4-di-(5-n-tridecylthien-2-yl)-benzene increases exponentially with
decreasing temperature. While qualitatively consistent with transport via
polaron bands, we find that it is quantitatively difficult to explain the
behaviour with physically realistic parameters. In particular, the data demand
either quite large typical optical phonon frequencies and/or phonon bandwidths.
We also find evidence that an unusually highly ordered smectic-F phase
templates the formation of lower temperature highly crystalline smectic phases,
which may have implications for device development.


title: Bounds on \"{U}bercrossing and Petal Numbers for Knots

abstract:
  An $n$-crossing is a point in the projection of a knot where $n$ strands
cross so that each strand bisects the crossing. An \"ubercrossing projection
has a single $n$-crossing and a petal projection has a single $n$-crossing such
that there are no loops nested within others. The \"ubercrossing number,
$\text{\"u}(K)$, is the smallest $n$ for which we can represent a knot $K$ with
a single $n$-crossing. The petal number is the number of loops in the minimal
petal projection. In this paper, we relate the \"{u}bercrossing number and
petal number to well-known invariants such as crossing number, bridge number,
and unknotting number. We find that the bounds we have constructed are tight
for $(r, r+1)$-torus knots. We also explore the behavior of \"{u}bercrossing
number under composition.


title: Idea Inheritance, Originality, and Collective Innovation

abstract:
  In order to create new products, inventors search and combine previous ideas.
Few studies have examined the characteristics of search that lead to new
products; most have focused on patent citations, which are often retrospective
and may not reflect the usefulness of inventions.
  Through the analysis of collaborations in an online virtual community, the
impact of originality on popularity and practicality is tested. These tests in
turn are based on a method for measuring the distance between 3D shapes. In
sum, this paper presents a new method for gauging innovation, and suggests ways
of further understanding the role technology plays in encouraging creativity.
From an organization perspective, this work provides insights into the creative
process, and in particular the open innovation process, in which thousands of
individuals together evolve designs, without belonging to the same corporate
structure, without claiming IP rights, without exchanging money.


title: Families of Legendrian Submanifolds via Generating Families

abstract:
  We investigate families of Legendrian submanifolds of 1-jet spaces by
developing and applying a theory of families of generating family homologies.
This theory allows us to detect an infinite family of loops of Legendrian
n-spheres embedded in the standard contact (2n+1)-space (for n>1) that are
contractible in the smooth, but not Legendrian, categories.


title: Networks of Innovation in 3D Printing

abstract:
  Innovation inside companies is difficult to see. But an emerging online
community of inventors who publicly post 3D CAD drawings of their work provide
a way to observe - and perhaps amplify - innovation. In this paper we analyze
the network structure of Thingiverse, a website oriented toward 3D printing.
This form of printing blurs the line between creating information and
manufacturing objects: drawings can be sent to devices that build 3D objects
out of many materials, including resin, ceramics, and metal. As an exploratory
study, we analyzed the structure of Thingiverse links. Our results suggest that
analysis of remix network structure may provide ways of tracing innovation
processes and detecting the emergence of new ideas, combination of disparate
ideas.


title:
Multivariate stochastic volatility modelling using Wishart
  autoregressive processes

abstract:
  A new multivariate stochastic volatility estimation procedure for financial
time series is proposed. A Wishart autoregressive process is considered for the
volatility precision covariance matrix, for the estimation of which a two step
procedure is adopted. The first step is the conditional inference on the
autoregressive parameters and the second step is the unconditional inference,
based on a Newton-Raphson iterative algorithm. The proposed methodology, which
is mostly Bayesian, is suitable for medium dimensional data and it bridges the
gap between closed-form estimation and simulation-based estimation algorithms.
An example, consisting of foreign exchange rates data, illustrates the proposed
methodology.


title: A note on triangulations of sum sets

abstract:
  For finite sets A and B in the plane, we write A+B to denote the set of sums
of the elements of A and B. In addition, we write tr(A) to denote the common
number of triangles in any triangulation of the convex hull of A using the
points of A as vertices. We consider the conjecture that tr(A+B)^{1/2}\geq
tr(A)^{1/2}+tr(B)^{1/2}. If true, this conjecture would be a discrete,
two-dimensional analogue to the Brunn-Minkowski inequality. We prove the
conjecture in three special cases.


title:
Dynamic scattering by cluster of small particles: local perturbation
  approach

abstract:
  The wave scattering by moving particles (dynamic scattering) is a well known
physical problem routinely occurring in practice. For the particles which are
much smaller than the incident wavelength, the static scattering problem can be
solved by using the local perturbation method. In this paper we apply the local
perturbation approach to the problem of the dynamic scattering by the cluster
of small particles. We calculate the fields scattered by the cluster of moving
particles. As an example, the scattered field is calculated for moving sphere
in scalar approximation and in vector case.


title: Warm inflation in presence of magnetic fields

abstract:
  We present preliminary results on the possible effects that primordial
magnetic fields can have for a warm inflation scenario, based on global
supersymmetry, with a new-inflation-type potential. This work is motivated by
two considerations: first, magnetic fields seem to be present in the universe
on all scales, which rises the possibility that they could also permeate the
early universe; second, the recent emergence of inflationary models where the
inflaton is not assumed to be isolated but instead it is taken as an
interacting field, even during the inflationary expansion. The effects of
magnetic fields are included resorting to Schwinger proper time method.


title:
Accurate curve fits of IAPWS data for high-pressure, high-temperature
  single-phase liquid water based on the stiffened gas equation of state

abstract:
  We present a series of optimal (in the sense of least-squares) curve fits for
the stiffened gas equation of state for single-phase liquid water. At high
pressures and (subcritical) temperatures, the parameters produced by these
curve fits are found to have very small relative errors: less than $1\%$ in the
pressure model, and less than $2\%$ in the temperature model. At low pressures
and temperatures, especially near the liquid-vapor transition line, the error
in the curve fits increases rapidly. The smallest pressure value for which
curve fits are reported in the present work is 25 MPa, high enough to ensure
that the fluid remains a single-phase liquid up to the maximum subcritical
temperature of approximately 647K.


title: Iterated functions and the Cantor set in one dimension

abstract:
  In this paper we consider the long-term behavior of points in ${\mathbb R}$
under iterations of continuous functions. We show that, given any Cantor set
$\Lambda^*$ embedded in ${\mathbb R}$, there exists a continuous function
$F^*:{\mathbb R}\to{\mathbb R}$ such that the points that are bounded under
iterations of $F^*$ are just those points in $\Lambda^*$. In the course of
this, we find a striking similarity between the way in which we construct the
Cantor middle-thirds set, and the way in which we find the points bounded under
iterations of certain continuous functions.


title:
The SPARQL2XQuery Interoperability Framework. Utilizing Schema Mapping,
  Schema Transformation and Query Translation to Integrate XML and the Semantic
  Web

abstract:
  The Web of Data is an open environment consisting of a great number of large
inter-linked RDF datasets from various domains. In this environment,
organizations and companies adopt the Linked Data practices utilizing Semantic
Web (SW) technologies, in order to publish their data and offer SPARQL
endpoints (i.e., SPARQL-based search services). On the other hand, the dominant
standard for information exchange in the Web today is XML. The SW and XML
worlds and their developed infrastructures are based on different data models,
semantics and query languages. Thus, it is crucial to develop interoperability
mechanisms that allow the Web of Data users to access XML datasets, using
SPARQL, from their own working environments. It is unrealistic to expect that
all the existing legacy data (e.g., Relational, XML, etc.) will be transformed
into SW data. Therefore, publishing legacy data as Linked Data and providing
SPARQL endpoints over them has become a major research challenge. In this
direction, we introduce the SPARQL2XQuery Framework which creates an
interoperable environment, where SPARQL queries are automatically translated to
XQuery queries, in order to access XML data across the Web. The SPARQL2XQuery
Framework provides a mapping model for the expression of OWL-RDF/S to XML
Schema mappings as well as a method for SPARQL to XQuery translation. To this
end, our Framework supports both manual and automatic mapping specification
between ontologies and XML Schemas. In the automatic mapping specification
scenario, the SPARQL2XQuery exploits the XS2OWL component which transforms XML
Schemas into OWL ontologies. Finally, extensive experiments have been conducted
in order to evaluate the schema transformation, mapping generation, query
translation and query evaluation efficiency, using both real and synthetic
datasets.


title:
High-energy collisions inside black holes and their counterpart in flat
  space-time

abstract:
  Two particles can collide inside a nonextremal black hole in such a way that
the energy E_{c.m.} in their centre of mass frame becomes as large as one
likes. We show that this effect can be understood with the help of a simple
analogy with particle collisions in flat space-time. As the two-dimensional
part of near-horizon geometry inside a black hole is described by the flat
Milne metric, the results have a general character. Full classification of
scenarios with unbound E_{c.m.} is suggested. Some scenarios of this kind
require proximity of collision to the bifurcation point, but for some other
ones this is not necessary.


title: A Normal Subgroup Theorem for Commensurators of Lattices

abstract:
  We establish a general normal subgroup theorem for commensurators of lattices
in locally compact groups. While the statement is completely elementary, its
proof, which rests on the original strategy of Margulis in the case of higher
rank lattices, relies heavily on analytic tools pertaining to amenability and
Kazhdan's property (T). It is a counterpart to the normal subgroup theorem for
irreducible lattices of Bader and the second named author, and may also be used
to sharpen that result when one of the ambient factors is totally disconnected.


title: Online and size anti-Ramsey numbers

abstract:
  A graph is properly edge-colored if no two adjacent edges have the same
color. The smallest number of edges in a graph any of whose proper edge
colorings contains a totally multicolored copy of a graph H is the size
anti-Ramsey number AR_s(H) of H. This number in offline and online setting is
investigated here.


title:
A conditional limit theorem for a bivariate representation of a
  univariate random variable and conditional extreme values

abstract:
  We consider a real random variable X represented through a random pair of
real random variables (R,T) and a deterministic function u as X=Ru(T). Under
some additional assumptions, we prove a limit theorem for (R,T) given X>x, as x
tends to infinity. As a consequence, we derive conditional limit theorems for
random pairs (X,Y)=(Ru(T),Rv(T)) given that X is large. These results imply
earlier ones which were obtained in the literature under stronger assumptions.


title: Free-configuration Biased Sampling for Motion Planning: Errata

abstract:
  This document contains improved and updated proofs of convergence for the
sampling method presented in our paper "Free-configuration Biased Sampling for
Motion Planning".


title:
A Study of Weakly Discontinuous Solutions for Hyperbolic Differential
  Equations Based on Wavelet Transform Methods

abstract:
  A new approach to prove the one-dimensional Cauchy problem's weakly
discontinuous solutions for hyperbolic PDEs are on the characteristics is
discussed in this paper. To do so, I use wavelet singularity detection methods
or WTMM [1] based on two-dimensional wavelet transform and combine it with the
Lipschitz index to strengthen the detection.


title: Optical Lattice Emulators: Bose and Fermi Hubbard Models

abstract:
  This chapter is a pedagogical review of the Hubbard model for bosons with
repulsion and for fermions with attraction and repulsion primarily using two
methods, one chosen for its simplicity and insights (mean field theory) and the
other chosen for its accuracy and reliability (quantum Monte Marlo methods).
From a comparison of the two methods we glean valuable information into the
effects of fluctuations that dominate quantum phase transitions. The chapter
includes an in-depth comparison with experiments. We conclude with a discussion
of future developments where the technical methods expounded on here, mean
field theory and quantum Monte Carlo, could be useful.


title: Theory of nonlinear phononics for coherent light-control of solids

abstract:
  We present a microscopic theory for ultrafast control of solids with
high-intensity terahertz frequency optical pulses. When resonant with selected
infrared-active vibrations, these pulses transiently modify the crystal
structure and lead to new collective electronic properties. The theory predicts
the dynamical path taken by the crystal lattice using first-principles
calculations of the energy surface and classical equations of motion, as well
as symmetry considerations. Two classes of dynamics are identified. In the
perturbative regime, displacements along the normal mode coordinate of
symmetry-preserving Raman active modes can be achieved by cubic
anharmonicities. This explains the light-induced insulator-to-metal transition
reported experimentally in manganites. We predict a regime in which ultrafast
instabilities that break crystal symmetry can be induced. This nonperturbative
effect involves a quartic anharmonic coupling and occurs above a critical
threshold, below which the nonlinear dynamics of the driven mode displays
softening and dynamical stabilization.


title:
Throwing Darts at a Ruler: Unpacking the Intuition Behind Freiling's
  Axiom of Symmetry

abstract:
  It is well-known that the Continuum Hypothesis (CH) is independent of the
other axioms of Zermelo-Fraenkel set theory with choice (ZFC). This raises the
question of whether an intuitive justification exists for CH as an additional
axiom, or conversely whether it is more intuitive to deny CH. Freiling's Axiom
of Symmetry (AS) is one candidate for an intuitively justifiable axiom that,
when appended to ZFC, is equivalent to the denial of CH. The intuition relies
on a probabalistic argument, usually cast in terms of throwing random darts at
the real line, and has been defended by researchers as well as popular writers.
In this note, the intuitive argument is reviewed. Following William Abram, it
is suggested that while accepting CH leads directly to a counterexample to AS,
this is not necessarily fatal to our intuition. Instead, we suggest, it serves
to alert us to the error in a naive intuition that leaps too readily from the
near-certainty of individual events to near-certainty of a joint event.


title:
On the non-randomness of maximum Lempel Ziv complexity sequences of
  finite size

abstract:
  Random sequences attain the highest entropy rate. The estimation of entropy
rate for an ergodic source can be done using the Lempel Ziv complexity measure
yet, the exact entropy rate value is only reached in the infinite limit. We
prove that typical random sequences of finite length fall short of the maximum
Lempel-Ziv complexity, contrary to common belief. We discuss that, for a finite
length, maximum Lempel-Ziv sequences can be built from a well defined
generating algorithm, which makes them of low Kolmogorov-Chaitin complexity,
quite the opposite to randomness. It will be discussed that Lempel-Ziv measure
is, in this sense, less general than Kolmogorov-Chaitin complexity, as it can
be fooled by an intelligent enough agent. The latter will be shown to be the
case for the binary expansion of certain irrational numbers. Maximum Lempel-Ziv
sequences induce a normalization that gives good estimates of entropy rate for
several sources, while keeping bounded values for all sequence length, making
it an alternative to other normalization schemes in use.