title: A message-passing approach for threshold models of behavior in networks

abstract:
  We study a simple model of how social behaviors, like trends and opinions,
propagate in networks where individuals adopt the trend when they are informed
by threshold $T$ neighbors who are adopters. Using a dynamic message-passing
algorithm, we develop a tractable and computationally efficient method that
provides complete time evolution of each individual's probability of adopting
the trend or of the frequency of adopters and non-adopters in any arbitrary
networks. We validate the method by comparing it with Monte Carlo based agent
simulation in real and synthetic networks and provide an exact analytic scheme
for large random networks, where simulation results match well. Our approach is
general enough to incorporate non-Markovian processes and to include
heterogeneous thresholds and thus can be applied to explore rich sets of
complex heterogeneous agent-based models.


title:
Correlation between thermodynamic anomalies and pathways of ice
  nucleation in supercooled water

abstract:
  The well-known classical nucleation theory (CNT) for the free energy barrier
towards formation of a nucleus of critical size of the new stable phase within
the parent metastable phase fails to take into account the influence of other
metastable phases having density/order intermediate between the parent
metastable phase and the final stable phase. This lacuna can be more serious
than capillary approximation or spherical shape assumption made in CNT. This
issue is particularly significant in ice nucleation because liquid water shows
rich phase diagram consisting of two (high and low density) liquid phases in
supercooled state. The explanations of thermodynamic and dynamic anomalies of
supercooled water often invoke the possible influence of a liquid-liquid
transition between two metastable liquid phases. To investigate both the role
of thermodynamic anomalies and presence of distinct metastable liquid phases in
supercooled water on ice nucleation, we employ density functional theoretical
approach to find nucleation free energy barrier in different regions of phase
diagram. The theory makes a number of striking predictions, such as a dramatic
lowering of nucleation barrier due to presence of a metastable intermediate
phase and crossover in the dependence of free energy barrier on temperature
near liquid-liquid critical point. These predictions can be tested by computer
simulations as well as by controlled experiments.


title: Lepton flavor violation decays of vector mesons in unparticle physics

abstract:
  We investigate the lepton flavor violation decays of vector mesons in the
scenario of the unparticle physics by considering the constraint from $\mu-e$
conversion. In unparticle physics, the predictions of LFV decays of vector
mesons depend strongly on the scale dimension $d_{\mathcal{U}}$. The
predictions of LFV decays of vector mesons can reach the detective sensitivity
in experiment in region of $3\le d_{\mathcal{U}}\le 4$, while the prediction of
$\mu-e$ conversion rate can meet the experimental upper limit. For the
searching of the lepton flavor violation processes of charged lepton sector in
experiment, the process $\Upsilon\rightarrow e\mu$ may be a promising one to be
observed.


title: Lepton flavor violation in inverse seesaw model

abstract:
  We analyze the lepton flavor violation processes $\mu-e$ conversion,
$l_i\rightarrow l_j\gamma$ and $l_i\rightarrow 3l_j$ in framework of the
Standard Model (SM) extended with inverse seesaw mechanism, as a function of
$\tilde{\eta} = 1 -|Det(\tilde {U}_{PMNS})|$ that parameterizes the departure
from unitary of the light neutrino mixing sub-matrix $\tilde {U}_{PMNS}$. In a
wide range of $\tilde{\eta}$, the predictions on the $\mu-e$ conversion rates
and the branching ratio of $\mu\rightarrow e\gamma$ are sizeable to be
compatible with the experimental upper limits or future experimental
sensitivities. For large scale of $\tilde{\eta}$, the predictions on branching
ratios of other lepton flavor processes can also be reach the experimental
upper limits or future experimental sensitivities. The value of $\tilde{\eta}$
depends on the determinant of the Majorana mass term $M_{\mu}$. Finally,
searching for lepton flavor violation processes in experiment provides us more
opportunities for the searches of seesaw nature of the neutrino masses.


title: Load Balancing using Ant Colony in Cloud Computing

abstract:
  Ants are very small insects.They are capable to find food even they are
complete blind. The ants lives in their nest and their job is to search food
while they get hungry. We are not interested in their living style, such as how
they live, how they sleep. But we are interested in how they search for food,
and how they find the shortest path. The technique for finding the shortest
path are now applying in cloud computing. The Ant Colony approach towards Cloud
Computing gives better performance.


title:
Dirac particles' tunnelling from 5-dimensional rotating black strings
  influenced by the generalized uncertainty principle

abstract:
  The standard Hawking formula predicts the complete evaporation of black
holes. Taking into account effects of quantum gravity, we investigate fermions'
tunnelling from a 5-dimensional rotating black string. The temperature is
determined not only by the string, but also affected by the quantum number of
the emitted fermion and the effect of the extra spatial dimension. The quantum
correction slows down the increase of the temperature, which naturally leads to
the remnant in the evaporation.


title:
Special bi-invariant linear connections on Lie groups and finite
  dimensional Poisson structures

abstract:
  Let $G$ be a connected Lie group and $\mathfrak{g}$ its Lie algebra. We
denote by $\nabla^0$ the torsion free bi-invariant linear connection on $G$
given by $\nabla^0_XY=\frac12[X,Y],$ for any left invariant vector fields
$X,Y$. A Poisson structure on $\mathfrak{g}$ is a commutative and associative
product on $\mathfrak{g}$ for which $\mathrm{ad}_u$ is a derivation, for any
$u\in\mathfrak{g}$.
  A torsion free bi-invariant linear connections on $G$ which have the same
curvature as $\nabla^0$ is called special. We show that there is a bijection
between the space of special connections on $G$ and the space of Poisson
structures on $\mathfrak{g}$. We compute the holonomy Lie algebra of a special
connection and we show that the Poisson structures associated to special
connections which have the same holonomy Lie algebra as $\nabla^0$ possess
interesting properties. Finally, we study Poisson structures on a Lie algebra
and we give a large class of examples which gives, of course, a large class of
special connections.


title:
Utility of galaxy catalogs for following up gravitational waves from
  binary neutron star mergers with wide-field telescopes

abstract:
  The first detections of gravitational waves from binary neutron star mergers
with advanced LIGO and Virgo observatories are anticipated in the next five
years. These detections could pave the way for multi-messenger
gravitational-wave (GW) and electromagnetic (EM) astronomy if GW triggers are
successfully followed up with targeted EM observations. However, GW sky
localization is relatively poor, with expected localization areas of ~10--100
square degrees; this presents a challenge for following up GW signals from
compact binary mergers. Prioritizing wide-field follow-ups based on the
probability of successful imaging is important when it is impossible to tile
the entire gravitational-wave localization region.
  Galaxy catalogs were effective at narrowing down regions of the sky to search
in initial attempts at joint GW/EM observations. The next generation of GW
detectors will have a ten-fold increase in range thereby increasing the
expected number of galaxies per unit solid angle a thousand-fold. As an
additional complication, catalogs may be highly incomplete.
  We show how to quantify the advantages of using galaxy catalogs as a function
of only two parameters: the three-dimensional volume within the field of view
of a telescope after accounting for the GW distance measurement uncertainty,
and the fraction of the GW sky localization uncertainty region that can be
followed up. We find that the use of galaxy catalogs can improve success rates
by ~10% to a factor of 4 relative to follow-up strategies that do not utilize
such catalogs for the scenarios we considered. We determine that catalogs with
a 75% completeness perform comparably to complete catalogs in most cases, while
33%-complete catalogs can lead to lower follow-up success rates than complete
catalogs for small fields of view, though still providing an advantage over
strategies that do not use a catalog at all.


title: On para-K\"ahler and hyper-para-K\"ahler Lie algebras

abstract:
  We study Lie algebras admitting para-K\"ahler and hyper-para-K\"ahler
structures. We give new characterizations of these Lie algebras and we develop
many methods to build large classes of examples. Bai considered para-K\"ahler
Lie algebras as left symmetric bialgebras. We reconsider this point of view and
improve it in order to obtain some new results. The study of para-K\"ahler and
hyper-para-K\"ahler is intimately linked to the study of left symmetric
algebras and, in particular, those admitting invariant symplectic forms. In
this paper, we give many new classes of left symmetric algebras and a complete
description of all associative algebras admitting an invariant symplectic form.
We give also all four dimensional hyper-para-K\"ahler Lie algebras.


title:
Variable Selection for Survival Data with A Class of Adaptive Elastic
  Net Techniques

abstract:
  The accelerated failure time (AFT) models have proved useful in many
contexts, though heavy censoring (as for example in cancer survival) and high
dimensionality (as for example in microarray data) cause difficulties for model
fitting and model selection. We propose new approaches to variable selection
for censored data, based on AFT models optimized using regularized weighted
least squares. The regularized technique uses a mixture of L1 and L2 norm
penalties under two proposed elastic net type approaches. One is the the
adaptive elastic net and the other is weighted elastic net. The approaches
extend the original approaches proposed by Ghosh (2007), and Hong and Zhang
(2010) respectively. We also extend the two proposed approaches by adding
censoring observations as constraints into their model optimization frameworks.
The approaches are evaluated on microarray and by simulation. We compare the
performance of these approaches with six other variable selection
techniques--three are generally used for censored data and the other three are
correlation-based greedy methods used for high-dimensional data.


title: k-Marked Dyson Symbols and Congruences for Moments of Cranks

abstract:
  By introducing $k$-marked Durfee symbols, Andrews found a combinatorial
interpretation of $2k$-th symmetrized moment $\eta_{2k}(n)$ of ranks of
partitions of $n$. Recently, Garvan introduced the $2k$-th symmetrized moment
$\mu_{2k}(n)$ of cranks of partitions of $n$ in the study of the higher-order
spt-function $spt_k(n)$. In this paper, we give a combinatorial interpretation
of $\mu_{2k}(n)$. We introduce $k$-marked Dyson symbols based on a
representation of ordinary partitions given by Dyson, and we show that
$\mu_{2k}(n)$ equals the number of $(k+1)$-marked Dyson symbols of $n$. We then
introduce the full crank of a $k$-marked Dyson symbol and show that there exist
an infinite family of congruences for the full crank function of $k$-marked
Dyson symbols which implies that for fixed prime $p\geq 5$ and positive
integers $r$ and $k\leq (p-1)/2$, there exist infinitely many non-nested
arithmetic progressions $An+B$ such that $\mu_{2k}(An+B)\equiv 0\pmod{p^r}$.


title: The Ramsey numbers of paths versus wheels: a complete solution

abstract:
  Let $G_1$ and $G_2$ be two given graphs. The Ramsey number $R(G_1,G_2)$ is
the least integer $r$ such that for every graph $G$ on $r$ vertices, either $G$
contains a $G_1$ or $\overline{G}$ contains a $G_2$. We denote by $P_n$ the
path on $n$ vertices and $W_m$ the wheel on $m+1$ vertices. Chen et al. and
Zhang determined the values of $R(P_n,W_m)$ when $m\leq n+1$ and when $n+2\leq
m\leq 2n$, respectively. In this paper we determine all the values of
$R(P_n,W_m)$ for the left case $m\geq 2n+1$. Together with Chen et al's and
Zhang's results, we give a complete solution to the problem of determining the
Ramsey numbers of paths versus wheels.


title: Pulsations of blue supergiants before and after helium core ignition

abstract:
  We present results of pulsation analyses of B-type supergiant models with
masses of $14 - 18 M_\odot$, considering evolutionary stages before and after
helium core ignition. Using a non-adiabatic pulsation code, we compute
instability domains for low degree modes. For selected models in these two
evolutionary phases, we compare properties of pulsation modes. Significant
differences are found in oscillation spectra and the kinetic energy density of
pulsation modes.


title: Code Coverage Based Test Case Selection and Prioritization

abstract:
  Regression Testing is exclusively executed to guarantee the desirable
functionality of existing software after pursuing quite a few amendments or
variations in it. Perhaps, it testifies the quality of the modified software by
concealing the regressions or software bugs in both functional and
non-functional applications of the system. In fact, the maintenance of test
suite is enormous as it necessitates a big investment of time and money on test
cases on a large scale. So, minimizing the test suite becomes the indispensable
requisite to lessen the budget on regression testing. Precisely, this research
paper aspires to present an innovative approach for the effective selection and
prioritization of test cases which in return may procure a maximum code
average.


title:
On the Origin of Highly Ionized X-ray Absorbers Detected in the Galactic
  X-ray Binaries

abstract:
  X-ray observations of the Galactic X-ray binaries (XRB) revealed numerous
highly ionized metal absorption lines. However, it is unclear whether such
lines are produced by the hot interstellar medium (ISM) or the circumstellar
medium (CSM) intrinsic to the binaries. Here we present a Chandra X-ray
absorption line study of 28 observations on 12 X-ray binaries, with a focus on
the NeIX and FeXVII lines. We report the first detections of these lines in a
significant amount of observations. We do not find significant dependence of
the line equivalent width on the distance of the XRBs, but we do see weak
dependence on the source X-ray luminosity. We also find two out of twelve
selected targets show strong temporal variation of the NeIX absorbers. While
the line ratio between the two ion species suggests a temperature consistent
with the previous predictions of the ISM, comparing with two theoretical models
of the ISM shows the observed column densities are significantly higher than
predictions. On the other hand, photoionzation by the XRBs provides reasonably
good fit to the data. Our findings suggest that a significant fraction of these
X-ray absorbers may originate in the hot gas intrinsic to the X-ray binaries,
and that the ISM makes small, if not negligible, contribution. We briefly
discuss the implications to the study of the Milky Way hot gas content.


title:
Relaxation Processes in Many Particle Systems -- Recurrence Relations
  Approach

abstract:
  The general scheme for the treatment of relaxation processes and temporal
autocorrelations of dynamical variables for many particle systems is presented
in framework of the recurrence relations approach. The time autocorrelation
functions and/or their spectral characteristics, which are measurable
experimentally (for example, due to spectroscopy techniques) and accessible
from particle dynamics simulations, can be found by means of this approach, the
main idea of which is the estimation of the so-called frequency parameters.
Model cases with the exact and approximative solutions are given and discussed.

categories: cond-mat.stat-mech cond-mat.dis-nn physics.comp-ph physics.flu-dyn


title:
Hierarchical complexity of 2-clique-colouring weakly chordal graphs and
  perfect graphs having cliques of size at least 3

abstract:
  A clique of a graph is a maximal set of vertices of size at least 2 that
induces a complete graph. A $k$-clique-colouring of a graph is a colouring of
the vertices with at most $k$ colours such that no clique is monochromatic.
D\'efossez proved that the 2-clique-colouring of perfect graphs is a
$\Sigma_2^P$-complete problem [J. Graph Theory 62 (2009) 139--156]. We
strengthen this result by showing that it is still $\Sigma_2^P$-complete for
weakly chordal graphs. We then determine a hierarchy of nested subclasses of
weakly chordal graphs whereby each graph class is in a distinct complexity
class, namely $\Sigma_2^P$-complete, $\mathcal{NP}$-complete, and
$\mathcal{P}$. We solve an open problem posed by Kratochv\'il and Tuza to
determine the complexity of 2-clique-colouring of perfect graphs with all
cliques having size at least 3 [J. Algorithms 45 (2002), 40--54], proving that
it is a $\Sigma_2^P$-complete problem. We then determine a hierarchy of nested
subclasses of perfect graphs with all cliques having size at least 3 whereby
each graph class is in a distinct complexity class, namely
$\Sigma_2^P$-complete, $\mathcal{NP}$-complete, and $\mathcal{P}$.


title:
Towards Structural Natural Language Formalization: Mapping Discourse to
  Controlled Natural Language

abstract:
  The author describes a conceptual study towards mapping grounded natural
language discourse representation structures to instances of controlled
language statements. This can be achieved via a pipeline of preexisting state
of the art technologies, namely natural language syntax to semantic discourse
mapping, and a reduction of the latter to controlled language discourse, given
a set of previously learnt reduction rules. Concludingly a description on
evaluation, potential and limitations for ontology-based reasoning is
presented.


title:
Realization of Tunable Photonic Spin Hall Effect by Tailoring the
  Pancharatnam-Berry Phase

abstract:
  Recent developments in the field of photonic spin Hall effect (SHE) offer new
opportunities for advantageous measurement of the optical parameters
(refractive index, thickness, etc.) of nanostructures and enable spin-based
photonics applications in the future. However, it remains a challenge to
develop a tunable photonic SHE with any desired spin-dependent splitting for
generation and manipulation of spin-polarized photons. Here, we demonstrate
experimentally a scheme to realize the photonic SHE tunably by tailoring the
space-variant Pancharatnam-Berry phase (PBP). It is shown that light beams
whose polarization with a tunable spatial inhomogeneity can contribute to
steering the space-variant PBP which creates a spin-dependent geometric phase
gradient, thereby possibly realizing a tunable photonic SHE with any desired
spin-dependent splitting. Our scheme provides a convenient method to manipulate
the spin photon. The results can be extrapolated to other physical system with
similar topological origins.


title:
Planck scale boundary conditions in the standard model with singlet
  scalar dark matter

abstract:
  We investigate Planck scale boundary conditions on the Higgs sector of the
standard model with a gauge singlet scalar dark matter. We will find that
vanishing self-coupling and Veltman condition at the Planck scale are realized
with the 126 GeV Higgs mass and top pole mass, 172 GeV $\lesssim M_t\lesssim$
173.5 GeV, where a correct abundance of scalar dark matter is obtained with
mass of 300 GeV $\lesssim m_S \lesssim$ 1 TeV. It means that the Higgs
potential is flat at the Planck scale, and this situation can not be realized
in the standard model with the top pole mass.


title: Quantum coherence in momentum space of light-matter condensates

abstract:
  We show that the use of momentum-space optical interferometry, which avoids
any spatial overlap between two parts of a macroscopic quantum state, presents
a unique way to study coherence phenomena in polariton condensates. In this
way, we address the longstanding question in quantum mechanics: "\emph{Do two
components of a condensate, which have never seen each other, possess a
definitive phase?}" [P. W. Anderson, \emph{Basic Notions of Condensed Matter
Physics} (Benjamin, 1984)]. A positive answer to this question is
experimentally obtained here for light-matter condensates, created under
precise symmetry conditions, in semiconductor microcavities taking advantage of
the direct relation between the angle of emission and the in-plane momentum of
polaritons.


title: Name: A Naming Mechanism for Delay/Disruption-Tolerant Network

abstract:
  This paper presents the design and implementation of the naming mechanism
(NAME), a resource discovery and service location approach for
Delay/Disruption-Tolerant Network (DTN). First discuss the architecture of NAME
mainly including Name Knowledge Base, Name Dissemination, Name Resolution and
Name-based Routing. In the design and implementation of NAME, we introduce the
simple namespecifiers to describe name, the name-tree for name storage and the
efficient predicate-based routing algorithm. Future work is finally discussed
for completing NAME and providing APIs for abundant applications.


title:
On Gauge Independence for Gauge Models with Soft Breaking of BRST
  Symmetry

abstract:
  A consistent quantum treatment of general gauge theories with an arbitrary
gauge-fixing in the presence of soft breaking of the BRST symmetry in the
field-antifield formalism is developed. It is based on a gauged (involving a
field-dependent parameter) version of finite BRST transformations. The
prescription allows one to restore the gauge-independence of the effective
action at its extremals and therefore also that of the conventional $S$-matrix
for a theory with BRST-breaking terms being additively introduced into a
BRST-invariant action in order to achieve a consistency of the functional
integral. We demonstrate the applicability of this prescription within the
approach of functional renormalization group to the Yang--Mills and gravity
theories. The Gribov--Zwanziger action and the refined Gribov--Zwanziger action
for a many-parameter family of gauges, including the Coulomb, axial and
covariant gauges, are derived perturbatively on the basis of finite gauged BRST
transformations starting from Landau gauge. It is proved that gauge theories
with soft breaking of BRST symmetry can be made consistent if the transformed
BRST-breaking terms satisfy the same soft BRST symmetry breaking condition in
the resulting gauge as the untransformed ones in the initial gauge, and also
without this requirement.


title: Anomalous Hall Effect in Chemically Disordered L10-Mn1.5Ga

abstract:
  The anomalous Hall effect (AHE) in perpendicularly magnetized L10-Mn1.5Ga
single-crystalline films is investigated as a function of degree of long-range
chemical ordering and temperature. Our results provide firm evidence that
phonons has negligibly smaller effect on skew scattering contributions to AHE
resistivity than defects, the overlook of which in conventional scaling laws
results in significant discrepancies and exponent n beyond 2 when fitting the
data. We find that the broken of long-range chemical ordering strongly affects
both intrinsic and extrinsic contributions of AHE conductivity, e.g., it
greatly suppresses intrinsic contributions by influencing the topology of the
band structures. Our results are of great importance for both physical
understanding and technological engineering of the AHE.


title:
Parallelization in Extracting Fresh Information from Online Social
  Network

abstract:
  Online Social Network (OSN) is one of the most hottest services in the past
years. It preserves the life of users and provides great potential for
journalists, sociologists and business analysts. Crawling data from social
network is a basic step for social network information analysis and processing.
As the network becomes huge and information on the network updates faster than
web pages, crawling is more difficult because of the limitations of band-width,
politeness etiquette and computation power. To extract fresh information from
social network efficiently and effectively, this paper presents a novel
crawling method and discusses parallelization architecture of social network.
To discover the feature of social network, we gather data from real social
network, analyze them and build a model to describe the discipline of users'
behavior. With the modeled behavior, we propose methods to predict users'
behavior. According to the prediction, we schedule our crawler more reasonably
and extract more fresh information with parallelization technologies.
Experimental results demonstrate that our strategies could obtain information
from OSN efficiently and effectively.


title:
Nitrogen-Containing Species in the Structure of the Synthesized
  Hydroxyapatite

abstract:
  Synthesized by the wet chemical precipitation technique hydroxyapatite
powders (HAp) with the sizes of the crystallites of (20-50) nm and 1000 nm were
analyzed by different analytical methods. By means of electron paramagnetic
resonance (EPR) it is shown that during the synthesis process nitrate anions
from the reagents (by-products) could incorporate into the HAp structure. The
concentration of the stable NO32- radicals detected after X-ray irradiation of
the product at room temperature does not decrease even after annealing up to
400 oC. The relaxation times and EPR parameters of the axially symmetric NO32-
paramagnetic centers are measured with high accuracy. Increased sensitivity and
resolution of high-frequency EPR (95 GHz) allows to reveal additional
paramagnetic centre(s) which origin is discussed. Analyses of electron-nuclear
double resonance (ENDOR) spectra from 1H and 31P nuclei and ab-initio density
functional theory (DFT) calculations allow suggesting that the paramagnetic
centers and nitrate anions as the precursors of NO32- radicals preferably
occupy PO43- site in the HAp structure.


title:
Harbinger: An Analyzing and Predicting System for Online Social Network
  Users' Behavior

abstract:
  Online Social Network (OSN) is one of the hottest innovations in the past
years, and the active users are more than a billion. For OSN, users' behavior
is one of the important factors to study. This demonstration proposal presents
Harbinger, an analyzing and predicting system for OSN users' behavior. In
Harbinger, we focus on tweets' timestamps (when users post or share messages),
visualize users' post behavior as well as message retweet number and build
adjustable models to predict users' behavior. Predictions of users' behavior
can be performed with the discovered behavior models and the results can be
applied to many applications such as tweet crawler and advertisement.


title: Quantum Lines for Dual Quasi-Bialgebras

abstract:
  In this paper, the theory to construct quantum lines for general dual
quasi-bialgebras is developed followed by some specific examples where the dual
quasi-bialgebras are pointed with cyclic group of points.


title: Uncertainty Measures and Limiting Distributions for Filament Estimation

abstract:
  A filament is a high density, connected region in a point cloud. There are
several methods for estimating filaments but these methods do not provide any
measure of uncertainty. We give a definition for the uncertainty of estimated
filaments and we study statistical properties of the estimated filaments. We
show how to estimate the uncertainty measures and we construct confidence sets
based on a bootstrapping technique. We apply our methods to astronomy data and
earthquake data.


title:
Teaching mathematics with a different philosophy. Part 1: Formal
  mathematics as biased metaphysics

abstract:
  We report on a pedagogical experiment to make mathematics easy by changing
its philosophy. The Western philosophy of math originated in religious beliefs
about mathesis, cursed by the church. Later, mathematics was "reinterpreted",
in a theologically-correct way, using the myth of "Euclid" and his deductive
proofs. The fact of the empirical proofs in the Elements, was, however,
contrary to this myth. The discrepancy was resolved by Hilbert and Russell who
rejected empirical proofs as unsound, reducing all mathematics to metaphysics.
We explain why that formalist metaphysics is anti-utilitarian and culturally
biased, not universal. Historically, most school-level math originated in the
non-West with a practical epistemology, but was absorbed in the West after
superimposing on it an incompatible Western metaphysics, still used to teach
it. This has made mathematics needlessly complex. Accordingly, math can be made
easy and more universal by reverting to a more practical epistemology.


title:
Teaching mathematics with a different philosophy. Part 2: Calculus
  without Limits

abstract:
  The example of the calculus is used to explain how simple, practical math was
made enormously complex by imposing on it the Western religiously-colored
notion of mathematics as "perfect". We describe a pedagogical experiment to
make math easy by teaching "calculus without limits" using the new realistic
philosophy of zeroism, different from Platonic idealism or formalist
metaphysics. Despite its demonstrated advantages, it is being resisted because
of the existing colonial hangover.


title:
PkANN - II. A non-linear matter power spectrum interpolator developed
  using artificial neural networks

abstract:
  In this paper we introduce PkANN, a freely available software package for
interpolating the non-linear matter power spectrum, constructed using
Artificial Neural Networks (ANNs). Previously, using Halofit to calculate
matter power spectrum, we demonstrated that ANNs can make extremely quick and
accurate predictions of the power spectrum. Now, using a suite of 6380 N-body
simulations spanning 580 cosmologies, we train ANNs to predict the power
spectrum over the cosmological parameter space spanning $3\sigma$ confidence
level (CL) around the concordance cosmology. When presented with a set of
cosmological parameters ($\Omega_{\rm m} h^2, \Omega_{\rm b} h^2, n_s, w,
\sigma_8, \sum m_\nu$ and redshift $z$), the trained ANN interpolates the power
spectrum for $z\leq2$ at sub-per cent accuracy for modes up to
$k\leq0.9\,h\textrm{Mpc}^{-1}$. PkANN is faster than computationally expensive
N-body simulations, yet provides a worst-case error $<1$ per cent fit to the
non-linear matter power spectrum deduced through N-body simulations. The
overall precision of PkANN is set by the accuracy of our N-body simulations, at
5 per cent level for cosmological models with $\sum m_\nu<0.5$ eV for all
redshifts $z\leq2$. For models with $\sum m_\nu>0.5$ eV, predictions are
expected to be at 5 (10) per cent level for redshifts $z>1$ ($z\leq1$). The
PkANN interpolator may be freely downloaded from
http://zuserver2.star.ucl.ac.uk/~fba/PkANN


title: Asymptotic trajectories of KAM torus

abstract:
  In this paper we construct a certain type of nearly integrable systems of two
and a half degrees of freedom:
  \[H(p,q,t)=h(p)+\epsilon f(p,q,t),\quad (q,p)\in T^{*}\mathbb{T}^2,t\in
\mathbb{S}^1=\mathbb{R}/\mathbb{Z},
  \] with a self-similar and weak-coupled $f(p,q,t)$ and $h(p)$ strictly
convex. For a given Diophantine rotation vector $\vec{\omega}$, we can find
asymptotic orbits towards the KAM torus $\mathcal{T}_{\omega}$, which persists
owing to the classical KAM theory, as long as $\epsilon\ll1$ sufficiently small
and $f\in C^r(T^{*}\mathbb{T}^2\times\mathbb{S}^1,\mathbb{R})$ properly smooth.
The construction bases on the new methods developed in {\it a priori} stable
Arnold Diffusion problem by Chong-Qing Cheng. As an expansion of that, this
paper sheds some light on the seeking of much preciser diffusion orbits.


title: A memo on chains and their topologies

abstract:
  We summarize some facts on chains (totally ordered sets), from an
order-theoretic and from a topological point of view. We highlight the fact
that many classical theorems that are true for partially ordered sets under
some completeness assumption remain true for chains without any kind of
completeness.


title: Boundary value problems for parabolic operators in a time-varying domain

abstract:
  We prove the existence of unique solutions to the Dirichlet boundary value
problems for linear second-order uniformly parabolic operators in either
divergence or non-divergence form with boundary blowup low-order coefficients.
The domain is possibly time varying, non-smooth, and satisfies the exterior
measure condition.


title: Maser Radiation in an Astrophysical Context (Overview)

abstract:
  In this paper we will look at the phenomenon of Microwave Amplification by
Stimulated Emission of Radiation (a maser system). We begin by deriving
amplification by stimulated emission using time-dependent perturbation theory,
in which the perturbation provided by external radiation. When this
perturbation is applied to an ensemble of particles exhibiting a population
inversion, the result is stimulated microwave radiation. We will explore both
unsaturated and saturated masers and compare their properties. By understanding
their gain, as well as the effect of line broadening, astronomers are to
identify astrophysical masers. By studying such masers, we gain new insight
into poorly understood physical environments, particularly those around young
and old stars, and compact stellar bodies.


title:
Paramagnetic alignment of small grains: a novel method for measuring
  interstellar magnetic fields

abstract:
  We present a novel method to measure the strength of interstellar magnetic
fields based on ultraviolet (UV) polarization of starlight, which is in part
produced by weakly aligned, small interstellar grains. We begin with
calculating degrees of alignment of small (size $a\sim 0.01\mu$m) and very
small ($a\sim 0.001\mu$m) grains in the interstellar magnetic field due to the
Davis-Greenstein paramagnetic relaxation and resonance paramagnetic relaxation.
We compute the degrees of paramagnetic alignment with the ambient magnetic
field $B$ using Langevin equations. In this paper, we take into account various
processes essential for the dynamics of small grains, including infrared (IR)
emission, electric dipole emission, plasma drag and collisions with neutral and
ionized species. We find that the alignment of small grains is necessary to
reproduce the observed polarization in the UV, although the polarization
arising from these small grains is negligible at the optical and IR
wavelengths. Based on fitting theoretical models to observed extinction and
polarization curves, we find that the best-fit model requires a higher degree
of alignment of small grains for the case with the peak wavelength of
polarization $\lambda_{\max}<0.55\mu$m, which exhibits an excess UV
polarization relative to the Serkowski law, compared to the typical case
$\lambda_{\max}=0.55\mu$m. We interpret the correlation between the systematic
increase of the UV polarization relative to maximum polarization (i.e. of
$p(6\mu m^{-1})/p_{\max}$) with $\lambda_{\max}^{-1}$ by appealing to the
higher degree of alignment of small grains. We identify paramagnetic relaxation
as the cause of the alignment of small grains and utilize the dependence of the
degree of alignment on the magnetic field strength $B$ to suggest a new way to
measure $B$ using the observable parameters $\lambda_{\max}$ and $p(6\mu
m^{-1})/p_{\max}$.[Abridged]


title: Strain induced superconductivity in the parent compound BaFe2As2

abstract:
  The discovery of superconductivity (SC) with a transition temperature, Tc, up
to 65K in single-layer FeSe (bulk Tc =8K) films grown on SrTiO3 substrates has
attracted special attention to Fe-based thin films. The high Tc is a
consequence of the combined effect of electron transfer from the oxygen-vacant
substrate to the FeSe thin film and lattice tensile strain. Here we demonstrate
the realization of SC in the parent compound BaFe2As2 (no bulk Tc) just by
tensile lattice strain without charge doping. We investigate the interplay
between strain and SC in epitaxial BaFe2As2 thin films on Fe-buffered MgAl2O4
single crystalline substrates. The strong interfacial bonding between Fe and
the FeAs sublattice increases the Fe-Fe distance due to the lattice misfit
which leads to a suppression of the antiferromagnetic spin density wave and
induces SC with bulk-Tc ?10K. These results highlight the role of structural
changes in controlling the phase diagram of Fe-based superconductors.


title: A Review: Study of Handover Performance in Mobile IP

abstract:
  The Mobile Internet Protocol (Mobile IP) is an extension to the Internet
Protocol proposed by the Internet Engineering Task Force (IETF) that addresses
the mobility issues. In order to support un-interrupted services and seamless
mobility of nodes across the networks (and/or sub-networks) with permanent IP
addresses, handover is performed in mobile IP enabled networks. Handover in
mobile IP is source cause of performance degradation as it results in increased
latency and packet loss during handover. Other issues like scalability issues,
ordered packet delivery issues, control plane management issues etc are also
adversely affected by it. The paper provides a constructive survey by
classifying, discussing and comparing different handover techniques that have
been proposed so far, for enhancing the performance during handovers. Finally
some general solutions that have been used to solve handover related problems
are briefly discussed.


title: Flat-Space Energy-Momentum Tensor from BMS/GCA Correspondence

abstract:
  Flat-space limit is well-defined for asymptotically AdS spacetimes written in
coordinates called the BMS gauge. For the three-dimensional Einstein gravity
with a negative cosmological constant, we calculate the quasi-local energy
momentum tensor in the BMS gauge and take its flat-space limit. In defining the
flat-space limit, we use the BMS/GCA correspondence which is a duality between
gravity in flat-spacetime and a field theory with Galilean conformal symmetry.
The resulting stress tensor reproduces correct values for conserved charges of
three dimensional asymptotically flat solutions. We show that the conservation
relation of the flat-space energy-momentum tensor is given by an
ultra-relativistic contraction of its relativistic counterpart. The
conservation equations correspond to Einstein equation for the flat metric
written in the BMS gauge. Our results provide further checks for the proposal
that the holographic dual of asymptotically flat spacetimes is a field theory
with Galilean conformal symmetry.


title: Analytical models of finite thin disks in a magnetic field

abstract:
  Analytical models of axially symmetric thin disks of finite extension in
presence of magnetic field are presented based on the well-known Morgan-Morgan
solutions. The source of the magnetic field is cons\-tructed separating the
equation corresponding to the Ampere's law of electrodynamics in spheroidal
oblate coordinates. This produces two asso\-ciated Legendre equations of first
order for the magnetic potential and hence that can be expressed as a series of
associated Legendre functions of the same order. The discontinuity of its
normal derivate across the disk allows us to interpret the source of the
magnetic field as a ringlike current distribution extended on all the plane of
the disk. We also study the circular speed curves or rotation curve for
equatorial circular orbits of charged test particles both inside and outside
the disk. The stability of the orbits is analyzed for radial perturbation using
a extension of the Rayleigh criterion.


title:
Theory of gyroresonance and free-free emissions from non-Maxwellian
  quasi-steady-state electron distributions

abstract:
  Currently there is a concern about ability of the classical thermal
(Maxwellian) distribution to describe quasi-steady-state plasma in solar
atmosphere including active regions. In particular, other distributions have
been proposed to better fit observations, for example, kappa- and
$n$-distributions. If present, these distributions will generate radio
emissions with different observable properties compared with the classical
gyroresonance (GR) or free-free emission, which implies a way of remote
detecting these non-Maxwellian distributions in the radio observations. Here we
present analytically derived GR and free-free emissivities and absorption
coefficients for the kappa- and $n$-distributions and discuss their properties,
which are in fact remarkably different from each other and from the classical
Maxwellian plasma. In particular, the radio brightness temperature from a
gyrolayer increases with the optical depth $\tau$ for kappa-distribution, but
decreases with $\tau$ for $n$-distribution. This property has a remarkable
consequence allowing a straightforward observational test: the gyroresonance
radio emission from the non-Maxwellian distributions is supposed to be
noticeably polarized even in the optically thick case, where the emission would
have strictly zero polarization in the case of Maxwellian plasma. This offers a
way of remote probing the plasma distribution in astrophysical sources
including solar active regions as a vivid example.


title:
Initial-boundary value problems for multi-term time-fractional diffusion
  equations with positive constant coefficients

abstract:
  In this paper, we investigate the well-posedness and the long-time asymptotic
behavior for the initial-boundary value problem for multi-term time-fractional
diffusion equations, where the time differentiation consists of a finite
summation of Caputo derivatives with decreasing orders in (0,1) and positive
constant coefficients. By exploiting several important properties of
multinomial Mittag-Leffler functions, various estimates follow from the
explicit solutions in form of these special functions. Then the uniqueness and
continuous dependency upon initial value and source term are established, from
which the continuous dependence of solution of Lipschitz type with respect to
various coefficients is also verified. Finally, by a Laplace transform
argument, it turns out that the decay rate of the solution as time tends to
infinity is dominated by the minimum order of the time-fractional derivatives.


title: Uniformly resolvable decompositions of $K_v$ into $P_3$ and $K_3$ graphs

abstract:
  In this paper we consider the uniformly resolvable decompositions of the
complete graph $K_v$, or the complete graph minus a 1-factor as appropriate,
into subgraphs such that each resolution class contains only blocks isomorphic
to the same graph. We completely determine the spectrum for the case in which
all the resolution classes are either $P_3$ or $K_3$.


title:
Critical groups of generalized de Bruijn and Kautz graphs and circulant
  matrices over finite fields: an extended abstract

abstract:
  We determine the critical groups of the generalized de Bruijn graphs
DB$(n,d)$ and generalized Kautz graphs Kautz$(n,d)$, thus extending and
completing earlier results for the classical de Bruijn and Kautz graphs.
Moreover, for a prime $p$ the critical groups of DB$(n,p)$ are shown to be in
close correspondence with groups of $n\times n$ circulant matrices over
$\mathbb{F}_p$, which explains numerical data in [OEIS:A027362], and suggests
the possibility to construct normal bases in $\mathbb{F}_{p^n}$ from spanning
trees in DB$(n,p)$.


title: Central force problem in space with SU(2) Poisson structure

abstract:
  The central force problem is considered in a three dimensional space in which
the Poisson bracket among the spatial coordinates is the one by the SU(2) Lie
algebra. It is shown that among attractive power-law potentials it is only the
Kepler one that all of its bound-states make closed orbits. The analytic
solution of the path equation under the Kepler potential is presented. It is
shown that except the Kepler potential, in contrast to ordinary space, all of
the potentials for which all of the almost circular orbits are closed are
non-power-law ones. For the non-power-law potentials examples of the numerical
solutions of the path equations are presented.


title: On operators with bounded approximation property

abstract:
  It is known that any separable Banach space with BAP is a complemented
subspace of a Banach space with a basis. We show that every operator with
bounded approximation property, acting from a separable Banach space, can be
factored through a Banach space with a basis.


title: A generating series for Murakami-Ohtsuki-Yamada graph evaluations

abstract:
  Murakami-Ohtsuki-Yamada introduced an evaluation of certain oriented planar
trivalent graphs with colored edges. This evaluation plays a key role in the
evaluation of the colored HOMFLY polynomial of a link in 3-space and its
Khovanov-Rozansky categorification. Our goal is is to give a generating series
formula for the evaluation of MOY graphs, which may be useful in
categorification, and in the study of q-holonomicity of the colored HOMFLY
polynomial.


title:
Pyroelectric and dielectric properties of calcium-barium niobate single
  crystals

abstract:
  Influence of the calcium concentration on the pyroelectric and dielectric
properties of CaxBa1-xNb2O6 (CBN) crystals in a wide temperature range was
studied. It is shown that calcium content (x) has an influence on the Curie
point position but has no effect on the dielectric hysteresis loop shape and
the appearance of temperature variations of dielectric permittivity, coercive
field and remanent polarization. At the same time, it is found that x affects
the polarization profile.


title: On the level sets of the Takagi-van der Waerden functions

abstract:
  This paper examines the level sets of the continuous but nowhere
differentiable functions \begin{equation*} f_r(x)=\sum_{n=0}^\infty
r^{-n}\phi(r^n x), \end{equation*} where $\phi(x)$ is the distance from $x$ to
the nearest integer, and $r$ is an integer with $r\geq 2$. It is shown, by
using properties of a symmetric correlated random walk, that almost all level
sets of $f_r$ are finite (with respect to Lebesgue measure on the range of
$f$), but that for an abscissa $x$ chosen at random from $[0,1)$, the level set
at level $y=f_r(x)$ is uncountable almost surely. As a result, the occupation
measure of $f_r$ is singular.


title:
Modeling of Contact Tracing in Epidemic Populations Structured by
  Disease Age

abstract:
  We consider an age-structured epidemic model with two basic public health
interventions: (i) identifying and isolating symptomatic cases, and (ii)
tracing and quarantine of the contacts of identified infectives. The dynamics
of the infected population are modeled by a nonlinear infection-age-dependent
partial differential equation, which is coupled with an ordinary differential
equation that describes the dynamics of the susceptible population. Theoretical
results about global existence and uniqueness of positive solutions are proved.
We also present two practical applications of our model: (1) we assess public
health guidelines about emergency preparedness and response in the event of a
smallpox bioterrorist attack; (2) we simulate the 2003 SARS outbreak in Taiwan
and estimate the number of cases avoided by contact tracing. Our model can be
applied as a rational basis for decision makers to guide interventions and
deploy public health resources in future epidemics.


title:
Engineering Cooperative JADE Agents with the AMCIS Methodology: The
  Transportation Management Case Study

abstract:
  This paper discusses in detail important analysis and design issues emerged
during the development of an agent-based transportation e-market. This
discussion is based on concepts coming from the AMCIS methodology and the JADE
framework. The AMCIS methodology is specifically tailored to the analysis and
design of cooperative information agent-based systems, while it supports both
the levels of the individual agent structure and the agent society in the
Multi-Agents Systems (MAS) development process. According to AMCIS, MAS are
viewed as being composed of a number of autonomous cooperative agents that live
in an organized society, in which each agent plays one or more specific roles,
while their plans and interaction protocols are well defined. On the other hand
JADE is a FIPA specifications compliant agent development environment that
gives several facilities for an easy and fast implementation. Our aim is to
reveal the mapping that may exists between the basic concepts proposed by AMCIS
for agents specification and agents interactions and those provided by JADE for
agents implementation, and therefore to propose a kind of roadmap for agents
developers.


title: Unirational threefolds with no universal codimension 2 cycle

abstract:
  We prove that the general quartic double solid with $k\leq 7$ nodes does not
admit a Chow theoretic decomposition of the diagonal, or equivalently has a
nontrivial universal ${\rm CH}_0$ group. The same holds if we replace in this
statement "Chow theoretic" by "cohomological". In particular, it is not stably
rational. We also prove that the general quartic double solid with seven nodes
does not admit a universal codimension 2 cycle parameterized by its
intermediate Jacobian, and even does not admit a parametrization with
rationally connected fibres of its Jacobian by a family of 1-cycles. This
implies that its third unramified cohomology group is not universally trivial.


title: Evolution of Semilocal String Networks: I. Large-scale Properties

abstract:
  We report on a detailed numerical study of the evolution of semilocal string
networks, based on the largest and most accurate field theory simulations of
these objects to date. We focus on the large-scale network properties,
confirming earlier indications (coming from smaller simulations) that linear
scaling is the attractor solution for the entire parameter space of initial
conditions that we are able to probe. We also provide a brief comparison of our
numerical results with the predictions of a previously developed one-scale
model for the overall evolution of these networks. Two subsequent papers will
discuss in more detail the analytic modeling of the semilocal segment
populations as well as optimized numerical diagnostics.


title: Dynamical phase transition in the simplest molecular chain model

abstract:
  We consider the dynamics of the simplest chain of large number $N$ of
particles. We find, in the double scaling limit, the partition of the parameter
space onto two domains, where for one domain the supremum (over all time
interval $(0,\infty)$ of relative extension tenda to $1$ as $N\to\infty$. and
for the other this supremum tends to infinity as $N\to\infty$.


title:
On the difficulties of acquiring mathematical experience: Case rural
  education

abstract:
  Based on a variety of philosophical approaches and my own work for decades in
pure and applied mathematics teaching and research, I explain my view upon the
basic difficulties of acquiring the Mathematical Experience (in the sense of
P.J. Davis and R. Hersh 1981) and submit a list of claims how these
difficulties can and should be confronted.


title: A remark on the well-posedness of the degenerated Zakharov system

abstract:
  We extend the local well-posedness theory for the Cauchy problem associated
to a degenerated Zakharov system. The new main ingredients are the derivation
of Strichartz and maximal function norm estimates for the linear solution of a
Schrodinger type equation with missing dispersion in one direction. The result
here improves the one in [11].


title: Simplicial nerve of an A-infinity category

abstract:
  In this paper we introduce a functor, called the simplicial nerve of an
A-infinity category, defined on the category of (small) A-infinity categories
with values in simplicial sets. We prove that the simplicial nerve of any
A-infinity category is an infinity category. This construction extends
functorially the nerve construction for differential graded categories proposed
by J.Lurie in Higher Algebra. We prove that if a differential graded category
is pretriangulated in the sense of A.I.Bondal-M.Kapranov, then its nerve is a
stable infinity category in the sense of J.Lurie.


title:
On the rate of convergence in Wasserstein distance of the empirical
  measure

abstract:
  Let $\mu_N$ be the empirical measure associated to a $N$-sample of a given
probability distribution $\mu$ on $\mathbb{R}^d$. We are interested in the rate
of convergence of $\mu_N$ to $\mu$, when measured in the Wasserstein distance
of order $p>0$. We provide some satisfying non-asymptotic $L^p$-bounds and
concentration inequalities, for any values of $p>0$ and $d\geq 1$. We extend
also the non asymptotic $L^p$-bounds to stationary $\rho$-mixing sequences,
Markov chains, and to some interacting particle systems.


title:
A moving fixed-interval filter/smoother for estimation of vehicle
  position using odometer and map-matched GPS

abstract:
  This paper presents some optimal real-time and post-processing estimators of
vehicle position using odometer and map-matched GPS measurements. These
estimators were based on a simple statistical error model of the odometer and
the GPS which makes the model generalizable to other applications. Firstly, an
asymptotically minimum variance unbiased estimator and two optimal moving fixed
interval filters which are more flexibles are exposed. Then, the
post-processing case leads to the construction of two moving fixed interval
smoothers. These estimators are tested and compared with the classical Kalman
filter with simulated and real data, and the results show a good accuracy of
each of them.


title:
Retro-Prospective Differential Inclusions and their Control by the
  Differential Connection Tensors of their Evolutions: The trendometer

abstract:
  This study is motivated by two different, yet, connected, motivations. The
first one follows the observation that the classical definition of derivatives
involves prospective (or forward) difference quotients, not known whenever the
time is directed, at least at the macroscopic level. Actually, the available
and known derivatives are retrospective (or backward). They co\"incide whenever
the functions are differentiable in the classical sense, but not in the case of
non smooth maps, single-valued or set-valued. The later ones are used in
differential inclusions (and thus, in uncertain control systems) governing
evolutions in function of time and state. We follow the plea of some physicists
for taking also into account the retrospective derivatives to study prospective
evolutions in function of time, state and retrospective derivatives, a
particular, but specific, example of historical of ''path dependent''
evolutionary systems. This is even more crucial in life sciences, in the
absence of experimentation of uncertain evolutionary systems. The second
motivation emerged from the study of networks with junctions (cross-roads in
traffic networks, synapses in neural networks, banks in financial networks,
etc.), an important feature of ''complex systems''. At each junction, the
velocities of the incoming (retrospective) and outgoing (prospective)
evolutions are confronted. One measure of this confrontation (''jerkiness'') is
provided by the product of the retrospective and prospective velocities,
negative in ''inhibitory'' junctions, positive for ''excitatory'' ones, for
instance. This leads to the introduction of the ''differential connection
tensor'' of two evolutions, defined as the tensor product of retrospective and
prospective derivatives, which can be used for controlling evolutionary systems
governing the evolutions through networks with junctions.


title:
Transports Regulators of Networks with Junctions Detected by Durations
  Functions

abstract:
  This study advocates a mathematical framework of ''transport relations'' on a
network. They single out a subset of ''traffic states'' described by time,
duration, position and other traffic attributes (called ''monads'' for short).
Duration evolutions are non-negative, decreasing toward zero for incoming
durations, increasing from zero for outgoing durations, allowing the detection
of ''junction states'' defined as traffic states with ''zero duration''. A
''junction relation'' (crossroads, synapses, clearing houses, etc.) Is a subset
of the transport relation made of junction states? The objective is to
construct a ''transport regulator'' associating with traffic states a set of
''celerities'' that mobiles circulating in the network can use as velocities.
In other word, a network is regarded as a ''provider of velocity information''
to the mobiles for travelling from one departure state to an arrival state
across a junction relation (a kind of geodesic problem). This investigation
assumes that a system governs the evolution of monads in function of time,
duration and position using celerities as controls and provides the transport
regulator, a feedback from transport states to celerities. The proposed
mathematical framework can acclimate road or aerial networks, endocrine
(hormonal) or synaptic (neurotransmitters) networks, financial or economic
networks, which motivated this investigation. This framework could probably
accommodate computer and even social networks. This investigation is restricted
to junctions between two routes.


title:
Robust Subspace System Identification via Weighted Nuclear Norm
  Optimization

abstract:
  Subspace identification is a classical and very well studied problem in
system identification. The problem was recently posed as a convex optimization
problem via the nuclear norm relaxation. Inspired by robust PCA, we extend this
framework to handle outliers. The proposed framework takes the form of a convex
optimization problem with an objective that trades off fit, rank and sparsity.
As in robust PCA, it can be problematic to find a suitable regularization
parameter. We show how the space in which a suitable parameter should be sought
can be limited to a bounded open set of the two dimensional parameter space. In
practice, this is very useful since it restricts the parameter space that is
needed to be surveyed.


title: Unity and Disunity in Mathematics

abstract:
  The unity of mathematics has its power to compactify experiences in a form
capable of being transferred and modified or adapted to new mathematical
situations. Yet, we believe that the phrase "Unity of Mathematics" expresses a
dream, an ideal that doesn't exist. We shall point to diachronic and cross
cultural disunities, to semantic, semiotic and philosophic ambiguities and to
the non-acceptance of certain mathematical texts by some practitioners of the
subject.


title: Substrate enhanced superconductivity in Li-decorated graphene

abstract:
  We investigate the role of the substrate for the strength of the electon
phonon coupling in Li-decorated graphene. We find that the interaction with a
$h$-BN substrate leads to a significant enhancement from $\lambda_0=0.62$ to
$\lambda_1=0.67$, which corresponds to a $25\%$ increase of the transition
temperature from $T_{c0}=10.33$ K to $T_{c1}=12.98$ K. The superconducting gaps
amount to 1.56 meV (suspended) and 1.98 meV (supported). These findings open up
a new route to enhanced superconducting transition temperatures in
graphene-based materials by substrate engineering.


title: A Repair Framework for Scalar MDS Codes

abstract:
  Several works have developed vector-linear maximum-distance separable (MDS)
storage codes that min- imize the total communication cost required to repair a
single coded symbol after an erasure, referred to as repair bandwidth (BW).
Vector codes allow communicating fewer sub-symbols per node, instead of the
entire content. This allows non trivial savings in repair BW. In sharp
contrast, classic codes, like Reed- Solomon (RS), used in current storage
systems, are deemed to suffer from naive repair, i.e. downloading the entire
stored message to repair one failed node. This mainly happens because they are
scalar-linear. In this work, we present a simple framework that treats scalar
codes as vector-linear. In some cases, this allows significant savings in
repair BW. We show that vectorized scalar codes exhibit properties that
simplify the design of repair schemes. Our framework can be seen as a finite
field analogue of real interference alignment. Using our simplified framework,
we design a scheme that we call clique-repair which provably identifies the
best linear repair strategy for any scalar 2-parity MDS code, under some
conditions on the sub-field chosen for vectorization. We specify optimal repair
schemes for specific (5,3)- and (6,4)-Reed- Solomon (RS) codes. Further, we
present a repair strategy for the RS code currently deployed in the Facebook
Analytics Hadoop cluster that leads to 20% of repair BW savings over naive
repair which is the repair scheme currently used for this code.


title: Long time decay to the Lei-Lin solution of 3D Navier-Stokes equations

abstract:
  In this paper we prove, if $u\in\mathcal C([0,\infty),{\bf {\mathcal
X}^{-1}}(\mathbb R^3))$ is global solution of 3D Navier-Stokes equations, then
$\|u(t)\|_{{\bf {\mathcal X}^{-1}}}$ decays to zero as time goes to infinity.
Fourier analysis and standard techniques are used.


title:
End-to-end Phoneme Sequence Recognition using Convolutional Neural
  Networks

abstract:
  Most phoneme recognition state-of-the-art systems rely on a classical neural
network classifiers, fed with highly tuned features, such as MFCC or PLP
features. Recent advances in ``deep learning'' approaches questioned such
systems, but while some attempts were made with simpler features such as
spectrograms, state-of-the-art systems still rely on MFCCs. This might be
viewed as a kind of failure from deep learning approaches, which are often
claimed to have the ability to train with raw signals, alleviating the need of
hand-crafted features. In this paper, we investigate a convolutional neural
network approach for raw speech signals. While convolutional architectures got
tremendous success in computer vision or text processing, they seem to have
been let down in the past recent years in the speech processing field. We show
that it is possible to learn an end-to-end phoneme sequence classifier system
directly from raw signal, with similar performance on the TIMIT and WSJ
datasets than existing systems based on MFCC, questioning the need of complex
hand-crafted features on large datasets.


title: A characterization related to a two-point boundary value problem

abstract:
  In this short note, we establish the following result: Let $f:[0,+\infty[\to
[0,+\infty[$, $\alpha:[0,1]\to ]0,+\infty[$ be two continuous functions, with
$f(0)=0$. Assume that, for some $a>0$, the function $\xi\to
{{\int_0^{\xi}f(t)dt}\over {\xi^2}}$ is non-increasing in $]0,a]$. Then, the
following assertions are equivalent: $(i)$ for each $b>0$, the function $\xi\to
{{\int_0^{\xi}f(t)dt}\over {\xi^2}}$ is not constant in $]0,b]$ ; $(ii)$ for
each $r>0$, there exists an open interval $I\subseteq ]0,+\infty[$ such that,
for every $\lambda\in I$, the problem $$\cases {-u''=\lambda\alpha(t)f(u) & in
$[0,1]$\cr & \cr u>0 & in $]0,1[$\cr & \cr u(0)=u(1)=0\cr}$$ has a solution $u$
satisfying $$\int_0^1|u'(t)|^2dt<r\ .$$


title:
Optimal rates for zero-order convex optimization: the power of two
  function evaluations

abstract:
  We consider derivative-free algorithms for stochastic and non-stochastic
convex optimization problems that use only function values rather than
gradients. Focusing on non-asymptotic bounds on convergence rates, we show that
if pairs of function values are available, algorithms for $d$-dimensional
optimization that use gradient estimates based on random perturbations suffer a
factor of at most $\sqrt{d}$ in convergence rate over traditional stochastic
gradient methods. We establish such results for both smooth and non-smooth
cases, sharpening previous analyses that suggested a worse dimension
dependence, and extend our results to the case of multiple ($m \ge 2$)
evaluations. We complement our algorithmic development with
information-theoretic lower bounds on the minimax convergence rate of such
problems, establishing the sharpness of our achievable results up to constant
(sometimes logarithmic) factors.


title:
A Comparative Study on Remote Tracking of Parkinsons Disease Progression
  Using Data Mining Methods

abstract:
  In recent years, applications of data mining methods are become more popular
in many fields of medical diagnosis and evaluations. The data mining methods
are appropriate tools for discovering and extracting of available knowledge in
medical databases. In this study, we divided 11 data mining algorithms into
five groups which are applied to a data set of patients clinical variables data
with Parkinsons Disease (PD) to study the disease progression. The data set
includes 22 properties of 42 people that all of our algorithms are applied to
this data set. The Decision Table with 0.9985 correlation coefficients has the
best accuracy and Decision Stump with 0.7919 correlation coefficients has the
lowest accuracy.


title: Dynamic Complexity of Planar 3-connected Graph Isomorphism

abstract:
  Dynamic Complexity (as introduced by Patnaik and Immerman) tries to express
how hard it is to update the solution to a problem when the input is changed
slightly. It considers the changes required to some stored data structure
(possibly a massive database) as small quantities of data (or a tuple) are
inserted or deleted from the database (or a structure over some vocabulary).
The main difference from previous notions of dynamic complexity is that instead
of treating the update quantitatively by finding the the time/space trade-offs,
it tries to consider the update qualitatively, by finding the complexity class
in which the update can be expressed (or made). In this setting, DynFO, or
Dynamic First-Order, is one of the smallest and the most natural complexity
class (since SQL queries can be expressed in First-Order Logic), and contains
those problems whose solutions (or the stored data structure from which the
solution can be found) can be updated in First-Order Logic when the data
structure undergoes small changes.
  Etessami considered the problem of isomorphism in the dynamic setting, and
showed that Tree Isomorphism can be decided in DynFO. In this work, we show
that isomorphism of Planar 3-connected graphs can be decided in DynFO+ (which
is DynFO with some polynomial precomputation). We maintain a canonical
description of 3-connected Planar graphs by maintaining a database which is
accessed and modified by First-Order queries when edges are added to or deleted
from the graph. We specifically exploit the ideas of Breadth-First Search and
Canonical Breadth-First Search to prove the results. We also introduce a novel
method for canonizing a 3-connected planar graph in First-Order Logic from
Canonical Breadth-First Search Trees.


title:
Predicting Flow Reversals in a Computational Fluid Dynamics Simulated
  Thermosyphon using Data Assimilation

abstract:
  A thermal convection loop is a circular chamber filled with water, heated on
the bottom half and cooled on the top half. With sufficiently large forcing of
heat, the direction of fluid flow in the loop oscillates chaotically, forming
an analog to the Earth's weather. As is the case for state-of-the-art weather
models, we only observe the statistics over a small region of state space,
making prediction difficult. To overcome this challenge, data assimilation
methods, and specifically ensemble methods, use the computational model itself
to estimate the uncertainty of the model to optimally combine these
observations into an initial condition for predicting the future state. First,
we build and verify four distinct DA methods. Then, a computational fluid
dynamics simulation of the loop and a reduced order model are both used by
these DA methods to predict flow reversals. The results contribute to a testbed
for algorithm development.


title: A composition theorem for parity kill number

abstract:
  In this work, we study the parity complexity measures
${\mathsf{C}^{\oplus}_{\min}}[f]$ and ${\mathsf{DT^{\oplus}}}[f]$.
${\mathsf{C}^{\oplus}_{\min}}[f]$ is the \emph{parity kill number} of $f$, the
fewest number of parities on the input variables one has to fix in order to
"kill" $f$, i.e. to make it constant. ${\mathsf{DT^{\oplus}}}[f]$ is the depth
of the shortest \emph{parity decision tree} which computes $f$. These
complexity measures have in recent years become increasingly important in the
fields of communication complexity \cite{ZS09, MO09, ZS10, TWXZ13} and
pseudorandomness \cite{BK12, Sha11, CT13}.
  Our main result is a composition theorem for ${\mathsf{C}^{\oplus}_{\min}}$.
The $k$-th power of $f$, denoted $f^{\circ k}$, is the function which results
from composing $f$ with itself $k$ times. We prove that if $f$ is not a parity
function, then ${\mathsf{C}^{\oplus}_{\min}}[f^{\circ k}] \geq
\Omega({\mathsf{C}_{\min}}[f]^{k}).$ In other words, the parity kill number of
$f$ is essentially supermultiplicative in the \emph{normal} kill number of $f$
(also known as the minimum certificate complexity).
  As an application of our composition theorem, we show lower bounds on the
parity complexity measures of $\mathsf{Sort}^{\circ k}$ and $\mathsf{HI}^{\circ
k}$. Here $\mathsf{Sort}$ is the sort function due to Ambainis \cite{Amb06},
and $\mathsf{HI}$ is Kushilevitz's hemi-icosahedron function \cite{NW95}. In
doing so, we disprove a conjecture of Montanaro and Osborne \cite{MO09} which
had applications to communication complexity and computational learning theory.
In addition, we give new lower bounds for conjectures of \cite{MO09,ZS10} and
\cite{TWXZ13}.


title:
Resonant Auger-intercoulombic hybridized decay in the photoionization of
  endohedral fullerenes

abstract:
  Considering the photoionization of Ar@C60, we predict resonant femtosecond
decays of both Ar and C60 vacancies through the continua of atom-fullerene
hybrid final states. The resulting resonances emerge from the interference
between simultaneous autoionizing and intercoulombic decay (ICD) processes. For
Ar 3s-->np excitations, these resonances are far stronger than the Ar-to-C60
resonant ICDs, while for C60 excitations they are strikingly larger than the
corresponding Auger features. The results indicate the power of hybridization
to enhance decay rates, and modify lifetimes and line profiles.


title:
Asymptotic Stability of POD based Model Predictive Control for a
  semilinear parabolic PDE

abstract:
  In this article a stabilizing feedback control is computed for a semilinear
parabolic partial differential equation utilizing a nonlinear model predictive
(NMPC) method. In each level of the NMPC algorithm the finite time horizon open
loop problem is solved by a reduced-order strategy based on proper orthogonal
decomposition (POD). A stability analysis is derived for the combined POD-NMPC
algorithm so that the lengths of the finite time horizons are chosen in order
to ensure the asymptotic stability of the computed feedback controls. The
proposed method is successfully tested by numerical examples.


title: Breakdown of continuum elasticity in amorphous solids

abstract:
  We show numerically that the response of simple amorphous solids (elastic
networks and particle packings) to a local force dipole is characterized by a
lengthscale $\ell_c$ that diverges as unjamming is approached as $\ell_c \sim
(z - 2d)^{-1/2}$, where $z \ge 2d$ is the mean coordination, and $d$ is the
spatial dimension, at odds with previous numerical claims. We also show how the
magnitude of the lengthscale $\ell_c$ is amplified by the presence of internal
stresses in the disordered solid. Our data suggests a divergence of $\ell_c\sim
(p_c-p)^{-1/4}$ with proximity to a critical internal stress $p_c$ at which
soft elastic modes become unstable.


title:
How the presence of a gas giant affects the formation of mean-motion
  resonances between two low-mass planets in a locally isothermal gaseous disc

abstract:
  In this paper we investigate the possibility of a migration-induced resonance
locking in systems containing three planets, namely an Earth analog, a
super-Earth and a gas giant. The planets have been listed in order of
increasing orbital periods. All three bodies are embedded in a locally
isothermal gaseous disc and orbit around a solar mass star. We are interested
in answering the following question: Will the low-mass planets form the same
resonant structures with each other in the vicinity of the gas giant as in the
case when the gas giant is absent? When there is no gas giant in the system, it
has been already shown that if the two low-mass planets undergo a convergent
differential migration, they will capture each other in a mean-motion
resonance. For the choices of disc parameters and planet masses made in this
paper, the formation of the 5:4 resonance in the absence of the Jupiter has
been observed. In this work we add a gas giant on the most external orbit of
the system in such a way that its differential migration is convergent with the
low-mass planets. We show that the result of this set-up is the speeding up of
the migration of the super-Earth and, after that, all three planets become
locked in a triple mean-motion resonance. However, this resonance is not
maintained due to the low-mass planet eccentricity excitation, a fact that
leads to close encounters between planets and eventually to the ejection from
the internal orbits of one or both low-mass planets.


title:
Radially global $\delta f$ computation of neoclassical phenomena in a
  tokamak pedestal

abstract:
  Conventional radially-local neoclassical calculations become inadequate if
the radial gradient scale lengths of the H-mode pedestal become as small as the
poloidal ion gyroradius. Here, we describe a radially global $\delta f$
continuum code that generalizes neoclassical calculations to allow stronger
gradients. As with conventional neoclassical calculations, the formulation is
time-independent and requires only the solution of a single sparse linear
system. We demonstrate precise agreement with an asymptotic analytic solution
of the radially global kinetic equation in the appropriate limits of aspect
ratio and collisionality. This agreement depends crucially on accurate
treatment of finite orbit width effects.


title:
A new proof of an Engelbert-Schmidt type zero-one law for
  time-homogeneous diffusions

abstract:
  In this paper we give a new proof to an Engelbert-Schmidt type zero-one law
for time-homogeneous diffusions, which provides deterministic criteria for the
convergence of integral functional of diffusions. Our proof is based on a
slightly stronger assumption than that in Mijatovi\'c and Urusov (2012), and
utilizes stochastic time change and Feller's test of explosions. It does not
rely on advanced methods such as the first Ray-Knight theorem, Wiliam's
theorem, Shepp's dichotomy result for Gaussian processes or Jeulin's lemma as
in the previous literature(see Mijatovi\'c and Urusov (2012) for a pointer to
the literature). The new proof has an intuitive interpretation as we link the
integral functional to the explosion time of an associated diffusion process.


title:
Polarized $\chi_{c2}$-charmonium production in antiproton-nucleus
  interactions

abstract:
  Starting from the Feynman diagram representation of multiple scattering we
consider the polarized $\chi_c$(1P)-charmonia production in antiproton-nucleus
reactions close to the threshold ($p_{\rm lab}=5-7$ GeV/c). The rescattering
and absorption of the incoming antiproton and outgoing charmonium on nucleons
are taken into account, including the possibility of the elastic and
nondiagonal (flavor-conserving) scattering $\chi_{cJ} N \to \chi_{cJ^\prime}
N$, $J,J^\prime=0,1,2$. The elementary amplitudes of the latter processes are
evaluated by expanding the physical $\chi_c$-states in the Clebsch-Gordan
series of the $c \bar c$ states with fixed values of internal orbital angular
momentum ($L_z$) and spin projections on the $\chi_c$ momentum axis. The total
interaction cross sections of these $c \bar c$ states with nucleons have been
calculated in previous works using the QCD factorization theorem and the
nonrelativistic quarkonium model and turned out to be strongly $L_z$-dependent
due to the transverse size difference. This directly leads to finite values of
the $\chi_c$-nucleon nondiagonal scattering amplitudes. We show that the
$\chi_{c0} N \to \chi_{c2} N$ transitions significantly influence the
$\chi_{c2}$-production with helicity zero at small transverse momenta. This can
serve as a signal in future experimental tests of the quark structure of
$\chi_c$-states by the PANDA collaboration at FAIR.


title: Limit Laws for Maxima of Contracted Stationary Gaussian Sequences

abstract:
  The principal results of this contribution are the weak and strong limits of
maxima of contracted stationary Gaussian random sequences. Due to the random
contraction we introduce a modified Berman condition which is sufficient for
the weak convergence of the maxima of the scaled sample. Under a stronger
assumption the weak convergence is strengthened to almost convergence.


title: Words and pronilpotent subgroups in profinite groups

abstract:
  Let $w$ be a multilinear commutator word, that is, a commutator of weight $n$
in $n$ different group variables. It is proved that if $G$ is a profinite group
in which all pronilpotent subgroups generated by $w$-values are periodic, then
the verbal subgroup $w(G)$ is locally finite.


title: Maxima of Skew Elliptical Triangular Arrays

abstract:
  In this paper we investigate the asymptotic behaviour of the componentwise
maxima for two bivariate skew elliptical triangular arrays with components
given in terms of skew transformations of bivariate spherical random vectors.
We find the weak limit of the normalized maxima for both cases that the random
radius pertaining to the elliptical random vectors is either in the Gumbel or
in the Weibull max-domain of attractions.


title:
Sequential Monte Carlo Inference of Mixed Membership Stochastic
  Blockmodels for Dynamic Social Networks

abstract:
  Many kinds of data can be represented as a network or graph. It is crucial to
infer the latent structure underlying such a network and to predict unobserved
links in the network. Mixed Membership Stochastic Blockmodel (MMSB) is a
promising model for network data. Latent variables and unknown parameters in
MMSB have been estimated through Bayesian inference with the entire network;
however, it is important to estimate them online for evolving networks. In this
paper, we first develop online inference methods for MMSB through sequential
Monte Carlo methods, also known as particle filters. We then extend them for
time-evolving networks, taking into account the temporal dependency of the
network structure. We demonstrate through experiments that the time-dependent
particle filter outperformed several baselines in terms of prediction
performance in an online condition.


title:
Tables, bounds and graphics of the smallest known sizes of complete arcs
  in the plane $\mathrm{PG}(2,q)$ for all $q\le160001$ and sporadic $q$ in the
  interval $[160801\ldots 430007]$

abstract:
  In the projective planes $\mathrm{PG}(2,q)$, we collect the smallest known
sizes of complete arcs for the regions \begin{align*} &\mbox{all }
q\le160001,~~ q \mbox{ prime power};\\ &Q_{4}=\{34 \mbox{ sporadic }q'\mbox{s
in the interval }[160801\ldots430007], \mbox{ see Table 3}\}. \end{align*}
  For $q\le160001$, the collection of arc sizes is complete in the sense that
arcs for all prime powers are considered. This proves new upper bounds on the
smallest size $t_{2}(2,q)$ of a complete arc in $\mathrm{PG}(2,q)$, in
particular \begin{align*} t_{2}(2,q)&<0.998\sqrt{3q\ln q}<1.729\sqrt{q\ln
q}&\mbox{ for }&&7&\le q\le160001;~~(1) \\
t_{2}(2,q)&<\sqrt{q}\ln^{0.7295}q&\mbox{ for }&&109&\le q\le160001;~~(2)\\
t_{2}(2,q)&<\sqrt{q}\ln^{c_{up}(q)}q,~~c_{up}(q)=\frac{0.27}{\ln q}+0.7,&\mbox{
for }&&19&\le q\le160001;~~(3)\\
t_{2}(2,q)&<0.6\sqrt{q}\ln^{\varphi_{up}(q;0.6)}
q,~~\varphi_{up}(q;0.6)=\frac{1.5}{\ln q}+0.802,&\mbox{ for }&&19&\le
q\le160001.~~(4) \end{align*} Moreover, the bounds (2) -- (4) hold also for
$q\in Q_{4}$. Also, \begin{align*} t_{2}(2,q)&<1.006\sqrt{3q\ln
q}<1.743\sqrt{q\ln q}&\mbox{ for }&&q\in Q_{4}.~~(5) \end{align*} Our
investigations and results allow to conjecture that the bounds (2) -- (5) hold
for all $q\geq109$.


title:
Characterization of the asymptotic Teichmuller space of the open unit
  disk through shears

abstract:
  We give a parametrization to the asymptotic Teichmuller space of the open
unit disk through equivalent classes of shear functions induced by
quasisymmetric homeomorphisms on the Farey tesselation of the unit disk. Then
using the parametrization, we define a new metric on the asymptotic Teichmuller
space. Two other related metrics are also introduced on the asymptotic
Teichmuller space by using cross-ratio distortions or quadrilateral dilatations
under the boundary maps on degenerating sequences of quadruples or
quadrilaterals. We show that the topologies induced by the three metrics are
equivalent to the one induced by the Teichmuller metric on the asymptotic
Teichmuller space. Before proving our main results, we revisit and rectify a
mistake in the proof in the reference [21] on the characterization of
quasisymmetric homeomorphisms in terms of shear functions.


title:
Exhibition of circular Bragg phenomenon by hyperbolic, dielectric,
  structurally chiral materials

abstract:
  The relative permittivity dyadic of a dielectric structurally chiral material
(SCM) varies helicoidally along a fixed direction; in consequence, the SCM
exhibits the circular Bragg phenomenon, which is the
circular-polarization-selective reflection of light. The introduction of
hyperbolicity in an SCM---by making either one or two but not all three
eigenvalues of the relative permittivity dyadic acquire negative real
parts---does not eliminate the circular Bragg phenomenon, but significantly
alters the regime for its exhibition. Physical vapor deposition techniques
appear to be suitable to fabricate hyperbolic SCMs.


title:
Geometric Representation of Interacting Non-Relativistic Open Strings
  using Extended Objects

abstract:
  Non-relativistic charged open strings coupled with Abelian gauge fields are
quantized in a geometric representation that generalizes the Loop
Representation. The model consists of open-strings interacting through a
Kalb-Ramond field in four dimensions. The geometric representation proposed
uses lines and surfaces that can be interpreted as an extension of the picture
of Faraday's lines of classical electromagnetism. This representation results
to be consistent, provided the coupling constant (the "charge" of the string)
is quantized. The Schr\"odinger equation in this representation is also
presented.


title:
Learning about social learning in MOOCs: From statistical analysis to
  generative model

abstract:
  We study user behavior in the courses offered by a major Massive Online Open
Course (MOOC) provider during the summer of 2013. Since social learning is a
key element of scalable education in MOOCs and is done via online discussion
forums, our main focus is in understanding forum activities. Two salient
features of MOOC forum activities drive our research: 1. High decline rate: for
all courses studied, the volume of discussions in the forum declines
continuously throughout the duration of the course. 2. High-volume, noisy
discussions: at least 30% of the courses produce new discussion threads at
rates that are infeasible for students or teaching staff to read through.
Furthermore, a substantial portion of the discussions are not directly
course-related.
  We investigate factors that correlate with the decline of activity in the
online discussion forums and find effective strategies to classify threads and
rank their relevance. Specifically, we use linear regression models to analyze
the time series of the count data for the forum activities and make a number of
observations, e.g., the teaching staff's active participation in the discussion
increases the discussion volume but does not slow down the decline rate. We
then propose a unified generative model for the discussion threads, which
allows us both to choose efficient thread classifiers and design an effective
algorithm for ranking thread relevance. Our ranking algorithm is further
compared against two baseline algorithms, using human evaluation from Amazon
Mechanical Turk.
  The authors on this paper are listed in alphabetical order. For media and
press coverage, please refer to us collectively, as "researchers from the EDGE
Lab at Princeton University, together with collaborators at Boston University
and Microsoft Corporation."


title:
Atomic-scale analysis of liquid-gallium embrittlement of aluminum grain
  boundaries

abstract:
  In this work, we explore the role of atomistic-scale energetics on
liquid-metal embrittlement of Al due to Ga. Ab initio and molecular mechanics
were employed to probe the binding energies of vacancies and segregation
energies of Ga for <100>, <110> and <111> STGBs in Al. We found that the GB
local arrangements and resulting structural units have a significant influence
on the magnitude of vacancy binding energies. For example, the mean vacancy
binding energy for <100>, <110>, and <111> STGBs at 1st layer was found to be
-0.63 eV, -0.26 eV, and -0.60 eV. However, some GBs exhibited vacancy binding
energies closer to bulk values, indicating interfaces with zero sink strength,
i.e., these GBs may not provide effective pathways for vacancy diffusion. The
results from the present work showed that the GB structure and the associated
free volume also play significant roles in Ga segregation and the subsequent
embrittlement of Al. The Ga mean segregation energy for <100>, <110> and <111>
STGBs at 1st layer was found to be -0.23 eV, -0.12 eV and -0.24 eV,
respectively, suggesting a stronger correlation between the GB structural unit,
its free volume, and segregation behavior. Furthermore, as the GB free volume
increased, the difference in segregation energies between the 1st layer and the
0th layer increased. Thus, the GB character and free volume provide an
important key to understanding the degree of anisotropy in various systems. The
overall characteristic Ga absorption length scale was found to be about ~10, 8,
and 12 layers for <100>, <110>, and <111> STGBs, respectively. Also, a few GBs
of different tilt axes with relatively high segregation energies (between 0 and
-0.1 eV) at the boundary were also found. This finding provides a new atomistic
perspective to the GB engineering of materials with smart GB networks to
mitigate or control LME and more general embrittlement phenomena in alloys.


title: $C^{m_0}$-Smoothness of Evaluation Maps

abstract:
  We give a proof that evaluation map $E: \Sigma^l\times {\cal M}\rightarrow
M^l$ is of class $C^{m_0}$.


title: Primordial magnetic fields from a non-singular bouncing cosmology

abstract:
  Although inflation is a natural candidate to generate the lengths of
coherence of magnetic fields needed to explain current observations, it needs
to break conformal invariance of electromagnetism to obtain significant
magnetic amplitudes. Of the simplest realizations are the kinetically-coupled
theories $f^2(\phi)F_{\mu\nu}F^{\mu\nu}$ (or $IFF$ theories). However, these
are known to suffer from electric fields backreaction or the strong coupling
problem. In this work we shall confirm that such class of theories are
problematic to support magnetogenesis during inflationary cosmology. On the
contrary, we show that a bouncing cosmology with a contracting phase dominated
by an equation of state with $p>-\rho/3$ can support magnetogenesis, evading
the {backreaction/strong-coupling problem}. Finally, we study safe
magnetogenesis in a particular bouncing model with an ekpyrotic-like
contracting phase. In this case we found that $f^2(\phi)F^2$-instabilities
might arise during the final kinetic-driven expanding phase for steep ekpyrotic
potentials.


title: Multipermutation Codes in the Ulam Metric for Nonvolatile Memories

abstract:
  We address the problem of multipermutation code design in the Ulam metric for
novel storage applications. Multipermutation codes are suitable for flash
memory where cell charges may share the same rank. Changes in the charges of
cells manifest themselves as errors whose effects on the retrieved signal may
be measured via the Ulam distance. As part of our analysis, we study
multipermutation codes in the Hamming metric, known as constant composition
codes. We then present bounds on the size of multipermutation codes and their
capacity, for both the Ulam and the Hamming metrics. Finally, we present
constructions and accompanying decoders for multipermutation codes in the Ulam
metric.


title: Budgeted Influence Maximization for Multiple Products

abstract:
  The typical algorithmic problem in viral marketing aims to identify a set of
influential users in a social network, who, when convinced to adopt a product,
shall influence other users in the network and trigger a large cascade of
adoptions. However, the host (the owner of an online social platform) often
faces more constraints than a single product, endless user attentions,
unlimited budget and unbounded time; in reality, multiple products need to be
advertised, each user can tolerate only a small number of recommendations,
influencing user has a cost and advertisers have only limited budgets, and the
adoptions need to be maximized within a short time window.
  Given theses myriads of user, monetary, and timing constraints, it is
extremely challenging for the host to design principled and efficient viral
market algorithms with provable guarantees. In this paper, we provide a novel
solution by formulating the problem as a submodular maximization in a
continuous-time diffusion model under an intersection of a matroid and multiple
knapsack constraints. We also propose an adaptive threshold greedy algorithm
which can be faster than the traditional greedy algorithm with lazy evaluation,
and scalable to networks with million of nodes. Furthermore, our mathematical
formulation allows us to prove that the algorithm can achieve an approximation
factor of $k_a/(2+2 k)$ when $k_a$ out of the $k$ knapsack constraints are
active, which also improves over previous guarantees from combinatorial
optimization literature. In the case when influencing each user has uniform
cost, the approximation becomes even better to a factor of $1/3$. Extensive
synthetic and real world experiments demonstrate that our budgeted influence
maximization algorithm achieves the-state-of-the-art in terms of both
effectiveness and scalability, often beating the next best by significant
margins.


title: Estimating constellations among primes - I. Uniformity

abstract:
  A few years ago we identified a recursion that works directly with the gaps
among the generators in each stage of Eratosthenes sieve. This recursion
provides explicit enumerations of sequences of gaps among the generators, which
are known as constellations.
  In this paper, we use those enumerations to estimate the numbers of these
constellations that occur as constellations among prime numbers, and we compare
these estimates with computational results. We include in our estimates the
constellations corresponding to three and four consecutive primes in arithmetic
progression.
  For these initial estimates, we assume that the copies of a given
constellation tend toward a uniform distribution in the cycle of gaps, as the
recursion progresses. Our simple estimates based on the recursion of gaps and
the assumption of uniformity appear to have correct asymptotic behavior, and
they exhibit a systematic error correlated to length of the constellation.


title: Log-concavity of a Mixture of Beta Distributions

abstract:
  We show that a mixture of Beta distributions has log-concave density whenever
the mixing weights are themselves log-concave. Some economic and statistical
applications are provided in the last section.


title: Twisted conjugacy in generalized Thompson groups of type F

abstract:
  If $\phi$ is an automorphism of a group $G$ and $x,y\in G$, we say that $x$
and $y$ are $\phi$-twisted conjugates if there exists an $z\in G$ such that
$y=z.x.\phi(z^{-1})$. This is an equivalence relation. If there are infinitely
many $\phi$-twisted conjugacy classes for every automorphism $\phi$ of $G$ we
say that $G$ has the $R_\infty$-property. We prove that the generalized Richard
Thompson groups $F_n$ and $F(l,A,P)$ have the $R_\infty$-property.


title: Mori dream surfaces associated with curves with one place at infinity

abstract:
  We study a class of rational surfaces (considered in [Campillo, Piltant and
Reguera, 2005]) associated to curves with one place at infinity and explicitly
describe generators of the Cox ring and global sections of line bundles on
these surfaces. In particular, we show that their Cox rings are finitely
generated, i.e. they are Mori dream spaces. We also compute their "global
Zariski semigroups at infinity" (consisting of line bundles which have no base
points `at infinity') and "global Enriques semigroups" (generated by closures
of curves in C^2). In particular, we show that the global Zariski semigroups at
infinity and Enriques semigroups of surfaces corresponding to pencils which are
equisingular at infinity are isomorphic, which answers a question of [Campillo,
Piltant and Reguera-Lopez, 2002]. We also give an effective algorithm to
determine if a (rational) surface `admits systems of numerical curvettes'
(these surfaces were also considered in [Campillo, Piltant and Reguera, 2005]).


title:
Spectral Efficiency and Outage Performance for Hybrid D2D-Infrastructure
  Uplink Cooperation

abstract:
  We propose a time-division uplink transmission scheme that is applicable to
future cellular systems by introducing hybrid device-to-device (D2D) and
infrastructure cooperation. We analyze its spectral efficiency and outage
performance and show that compared to existing frequency-division schemes, the
proposed scheme achieves the same or better spectral efficiency and outage
performance while having simpler signaling and shorter decoding delay. Using
time-division, the proposed scheme divides each transmission frame into three
phases with variable durations. The two user equipments (UEs) partially
exchange their information in the first two phases, then cooperatively transmit
to the base station (BS) in the third phase. We further formulate its common
and individual outage probabilities, taking into account outages at both UEs
and the BS. We analyze this outage performance in Rayleigh fading environment
assuming full channel state information (CSI) at the receivers and limited CSI
at the transmitters. Results show that comparing to non-cooperative
transmission, the proposed cooperation always improves the instantaneous
achievable rate region even under half-duplex transmission. Moreover, as the
received signal-to-noise ratio increases, this uplink cooperation significantly
reduces overall outage probabilities and achieves the full diversity order in
spite of additional outages at the UEs. These characteristics of the proposed
uplink cooperation make it appealing for deployment in future cellular
networks.


title: A Class of Kazhdan-Lusztig R-Polynomials and q-Fibonacci Numbers

abstract:
  Let $S_n$ denote the symmetric group on $\{1,2,\ldots,n\}$. For two
permutations $u, v\in S_n$ such that $u\leq v$ in the Bruhat order, let
$R_{u,v}(q)$ and $\R_{u,v}(q)$ denote the Kazhdan-Lusztig $R$-polynomial and
$\R$-polynomial, respectively. Let $v_n=34\cdots n\, 12$, and let $\sigma$ be a
permutation such that $\sigma\leq v_n$. We obtain a formula for the
$\R$-polynomials $\R_{\sigma,v_n}(q)$ in terms of the $q$-Fibonacci numbers
depending on a parameter determined by the reduced expression of $\sigma$. When
$\sigma$ is the identity $e$, this reduces to a formula obtained by Pagliacci.
In another direction, we obtain a formula for the $\R$-polynomial
$\R_{e,\,v_{n,i}}(q)$, where $v_{n,i} = 3 4\cdots i\,n\, (i+1)\cdots (n-1)\,
12$. In a more general context, we conjecture that for any two permutations
$\sigma,\tau\in S_n$ such that $\sigma\leq \tau\leq v_n$, the $\R$-polynomial
$\R_{\sigma,\tau}(q)$ can be expressed as a product of $q$-Fibonacci numbers
multiplied by a power of $q$.


title: bartMachine: Machine Learning with Bayesian Additive Regression Trees

abstract:
  We present a new package in R implementing Bayesian additive regression trees
(BART). The package introduces many new features for data analysis using BART
such as variable selection, interaction detection, model diagnostic plots,
incorporation of missing data and the ability to save trees for future
prediction. It is significantly faster than the current R implementation,
parallelized, and capable of handling both large sample sizes and
high-dimensional data.


title: Stanley's Lemma and Multiple Theta Functions

abstract:
  We present an algorithmic approach to the verification of identities on
multiple theta functions in the form of products of theta functions
$[(-1)^{\delta}a_1^{\alpha_1}a_2^{\alpha_2}\cdots a_r^{\alpha_r}q^{s};
q^{t}]_\infty$, where $\alpha_i$ are integers, $\delta=0$ or $1$, $s\in
\mathbb{Q}$, $t\in \mathbb{Q}^{+}$, and the exponent vectors
$(\alpha_1,\alpha_2,\ldots,\alpha_r)$ are linearly independent over
$\mathbb{Q}$. For an identity on such multiple theta functions, we provide an
algorithmic approach for computing a system of contiguous relations satisfied
by all the involved multiple theta functions. Using Stanley's Lemma on the
fundamental parallelepiped, we show that a multiple theta function can be
determined by a finite number of its coefficients. Thus such an identity can be
reduced to a finite number of simpler relations. Many classical multiple theta
function identities fall into this framework, including Riemann's addition
formula and the extended Riemann identity.