title: Phase Space Distribution of Riemann Zeros

abstract:
  We present the partition function of a most generic $U(N)$ single plaquette
model in terms of representations of unitary group. Extremising the partition
function in large N limit we obtain a relation between eigenvalues of unitary
matrices and number of boxes in the most dominant Young tableaux distribution.
Since, eigenvalues of unitary matrices behave like coordinates of free fermions
whereas, number of boxes in a row is like conjugate momenta of the same, a
relation between them allows us to provide a phase space distribution for
different phases of the unitary model under consideration. This proves a
universal feature that all the phases of a generic unitary matrix model can be
described in terms of topology of free fermi phase space distribution. Finally,
using this result and analytic properties of resolvent that satisfy
Dyson-Schwinger equation, we present a phase space distribution of unfolded
zeros of Riemann zeta function.


title:
The galaxy counterpart of the high-metallicity and 16 kpc impact
  parameter DLA towards Q0918+1636 - a challenge to galaxy formation models?

abstract:
  The quasar Q0918+1636 (z=3.07) has an intervening high-metallicity Damped
Lyman-alpha Absorber (DLA) along the line of sight, at a redshift of z=2.58.
The DLA is located at a large impact parameter of 16.2 kpc, and has an almost
solar metallicity. It is shown, that a novel type of cosmological galaxy
formation models, invoking a new SNII feedback prescription, the Haardt & Madau
(2012) UVB field and explicit treatment of UVB self-shielding, can reproduce
the observed characteristics of the DLA. UV radiation from young stellar
populations in the galaxy, in particular in the photon energy range 10.36-13.61
eV (relating to Sulfur II abundance), are also considered in the analysis. It
is found that a) for L~L* galaxies (at z=2.58), about 10% of the sight-lines
through the galaxies at impact parameter 16.2 kpc will display a Sulfur II
column density N(SII)$>$ 10$^{15.82}$ cm$^{-2}$ (the observed value for the
DLA), and b) considering only cases where a near-solar metallicity will be
detected at 16.2 kpc impact parameter, the probability distribution of galaxy
SFR peaks near the value observed for the DLA galaxy counterpart of ~27
Msun/yr. It is argued, that the bulk of the alpha-elements, like Sulfur, traced
by the high metal column density, b=16.2 kpc absorption lines, were produced by
evolving young stars in the inner galaxy, and later transported outward by
galactic winds.


title: Momentum transfer dependence of generalized parton distributions

abstract:
  We revisit the model for parametrization of momentum dependence of nucleon
generalized parton distributions in the light of recent MRST measurements of
parton distribution functions. Our parametrization method with minimum set of
free parameters give a sufficiently good description of data for Dirac and
Pauli electromagnetic form factors of proton and neutron at small and
intermediate values of momentum transfer. We also calculate the GPDs for up and
down quark by decomposing the electromagnetic form factors for nucleon using
the charge and isospin symmetry and also study the evolution of GPDs to a
higher scale. We further investigate the transverse charge densities for both
the unpolarized and transversely polarized nucleon and compare our results with
the Kelly's distribution.


title: Nuclear Group Algebras for Finitely Generated Groups

abstract:
  We study completions of the group algebra of a finitely generated group and
relate nuclearity of such a completion to growth properties of the group. This
extends previous work of Jolissaint on nuclearity of rapidly decreasing
functions on a finitely generated group to more general weights than polynomial
decrease. The new group algebras and their duals are studied in detail and
compared to other approaches. As application we discuss the convergence of the
complete growth function introduced by Grigorchuk and Nagnibeda.


title: Observation of Reflectance Fluctuations in Metals

abstract:
  Through the study of the power spectra of a monochromatic light beam
reflected by metallic mirrors, fluctuations in their reflectance is observed.
The power spectra were obtained down to a factor $10^{-6}$ below the Standard
Quantum Limit, with a dynamic range of $10^5$ in the frequency and power, using
methods we developed. The properties of the spectra are investigated and their
dependence on the material is analyzed. The physics underlying the phenomenon
is also discussed. These fluctuations provide a new window for investigating
the inner workings of materials.


title:
Balancing, Regression, Difference-In-Differences and Synthetic Control
  Methods: A Synthesis

abstract:
  In a seminal paper Abadie, Diamond, and Hainmueller [2010] (ADH), see also
Abadie and Gardeazabal [2003], Abadie et al. [2014], develop the synthetic
control procedure for estimating the effect of a treatment, in the presence of
a single treated unit and a number of control units, with pre-treatment
outcomes observed for all units. The method constructs a set of weights such
that selected covariates and pre-treatment outcomes of the treated unit are
approximately matched by a weighted average of control units (the synthetic
control). The weights are restricted to be nonnegative and sum to one, which is
important because it allows the procedure to obtain unique weights even when
the number of lagged outcomes is modest relative to the number of control
units, a common setting in applications. In the current paper we propose a
generalization that allows the weights to be negative, and their sum to differ
from one, and that allows for a permanent additive difference between the
treated unit and the controls, similar to difference-in-difference procedures.
The weights directly minimize the distance between the lagged outcomes for the
treated and the control units, using regularization methods to deal with a
potentially large number of possible control units.


title:
Critical Capillary Number of Interfacial Film Displacement in a
  Capillary Tube

abstract:
  The role of surface tension and wettability in the dynamics of air-liquid
interfaces during immiscible fluid displacement flows in capillary tube driven
by pressure has been investigated. The contact angle and capillary number drive
the force wetting processes which is controlled by the balance between the
capillary and the viscous lubrication forces. The dynamic wetting condition
with the critical capillary number is studied analytically and validated
experimentally, which demonstrates that the critical capillary number is
associated with the contact angle, slip length and capillary radius.


title:
On the uniqueness of the Myers-Perry spacetime as a type II(D) solution
  in six dimensions

abstract:
  We study the class of vacuum (Ricci flat) six-dimensional spacetimes
admitting a non-degenerate multiple Weyl aligned null direction l, thus being
of Weyl type II or more special. Subject to an additional assumption on the
asymptotic fall-off of the Weyl tensor, we prove that these spacetimes can be
completely classified in terms of the two eigenvalues of the (asymptotic) twist
matrix of l and of a discrete parameter $U^0=\pm 1/2, 0$. All solutions turn
out to be Kerr-Schild spacetimes of type D and reduce to a family of
"generalized" Myers-Perry metrics (which include limits and analytic
continuations of the original Myers-Perry black hole metric, such as certain
NUT spacetimes). A special subcase corresponds to twisting solutions with zero
shear. In passing, limits connecting various branches of solutions are briefly
discussed.


title:
Fast preparation of W states with superconducting quantum interference
  devices by using dressed states

abstract:
  In this paper, we propose a protocol to prepare W states with superconducting
quantum interference devices (SQUID) by using dressed states. Through choosing
a set of dressed states suitably, the protocol can be used to accelerate the
adiabatic passages while additional couplings are unnecessary. Moreover, we can
optimize the evolution of the system with the restraint to the populations of
the intermediate states by choosing suitable controlled parameters. Numerical
simulations show that the protocol is robust against the parameter variations
and decoherence mechanisms. Furthermore, the protocol is faster and more robust
against the dephasing, compared with that by the adiabatic passages. As for the
Rabi frequencies of pulses designed by the method, they can be expressed by the
linear superpositions of Gaussian functions, which does not increase
difficulties to the experiments. In addition, the protocol could be controlled
and manipulated easily in experiments with a circuit quantum electrodynamics
system.


title:
Big Models for Big Data using Multi objective averaged one dependence
  estimators

abstract:
  Even though, many researchers tried to explore the various possibilities on
multi objective feature selection, still it is yet to be explored with best of
its capabilities in data mining applications rather than going for developing
new ones. In this paper, multi-objective evolutionary algorithm ENORA is used
to select the features in a multi-class classification problem. The fusion of
AnDE (averaged n-dependence estimators) with n=1, a variant of naive Bayes with
efficient feature selection by ENORA is performed in order to obtain a fast
hybrid classifier which can effectively learn from big data. This method aims
at solving the problem of finding optimal feature subset from full data which
at present still remains to be a difficult problem. The efficacy of the
obtained classifier is extensively evaluated with a range of most popular 21
real world dataset, ranging from small to big. The results obtained are
encouraging in terms of time, Root mean square error, zero-one loss and
classification accuracy.


title: A Novel Boundary Matching Algorithm for Video Temporal Error Concealment

abstract:
  With the fast growth of communication networks, the video data transmission
from these networks is extremely vulnerable. Error concealment is a technique
to estimate the damaged data by employing the correctly received data at the
decoder. In this paper, an efficient boundary matching algorithm for estimating
damaged motion vectors (MVs) is proposed. The proposed algorithm performs error
concealment for each damaged macro block (MB) according to the list of
identified priority of each frame. It then uses a classic boundary matching
criterion or the proposed boundary matching criterion adaptively to identify
matching distortion in each boundary of candidate MB. Finally, the candidate MV
with minimum distortion is selected as an MV of damaged MB and the list of
priorities is updated. Experimental results show that the proposed algorithm
improves both objective and subjective qualities of reconstructed frames
without any significant increase in computational cost. The PSNR for test
sequences in some frames is increased about 4.7, 4.5, and 4.4 dB compared to
the classic boundary matching, directional boundary matching, and directional
temporal boundary matching algorithm, respectively.


title:
Activity Maximization by Effective Information Diffusion in Social
  Networks

abstract:
  In a social network, even about the same information the excitements between
different pairs of users are different. If you want to spread a piece of new
information and maximize the expected total amount of excitements, which seed
users should you choose? This problem indeed is substantially different from
the renowned influence maximization problem and cannot be tackled using the
existing approaches. In this paper, motivated by the demand in a few
interesting applications, we model the novel problem of activity maximization.
We tackle the problem systematically. We first analyze the complexity and the
approximability of the problem. We develop an upper bound and a lower bound
that are submodular so that the Sandwich framework can be applied. We then
devise a polling-based randomized algorithm that guarantees a data dependent
approximation factor. Our experiments on three real data sets clearly verify
the effectiveness and scalability of our method, as well as the advantage of
our method against the other heuristic methods.


title: Global rigidity of generic frameworks on the cylinder

abstract:
  We show that a generic framework $(G,p)$ on the cylinder is globally rigid if
and only if $G$ is a complete graph on at most four vertices or $G$ is both
redundantly rigid and $2$-connected. To prove the theorem we also derive a new
recursive construction of circuits in the simple $(2,2)$-sparse matroid, and a
characterisation of rigidity for generic frameworks on the cylinder when a
single designated vertex is allowed to move off the cylinder.


title: Singular Fibers and Kodaira Dimensions

abstract:
  Let $f:\,X \to \mathbb{P}^1$ be a non-isotrivial semi-stable family of
varieties of dimension $m$ over $\mathbb{P}^1$ with $s$ singular fibers. Assume
that the smooth fibers $F$ are minimal, i.e., their canonical line bundles are
semiample. Then $\kappa(X)\leq \kappa(F)+1$. If $\kappa(X)=\kappa(F)+1$, then
$s>\frac{4}m+2$. If $\kappa(X)\geq 0$, then $s\geq\frac{4}m+2$. In particular,
if $m=1$, $s=6$ and $\kappa(X)=0$, then the family $f$ is Teichm\"uller.


title: Quasi-flat plasmonic bands in twisted bilayer graphene

abstract:
  The charge susceptibility of twisted bilayer graphene is investigated in the
Dirac cone, respectively random-phase approximation. For small enough twist
angles $\theta\lesssim 2^\circ$ we find weakly Landau damped interband
plasmons, i.~e., collective excitonic modes which exist in the undoped
material, with an almost constant energy dispersion. In this regime, the loss
function can be described as a Fano resonance and we argue that these
excitations arise from the interaction of quasi-localised states with the
incident light field. These predictions can be tested by nano-infrared imaging
and possible applications include a "perfect" lens without the need of
left-handed materials.


title: Image Clustering without Ground Truth

abstract:
  Cluster analysis has become one of the most exercised research areas over the
past few decades in computer science. As a consequence, numerous clustering
algorithms have already been developed to find appropriate partitions of a set
of objects. Given multiple such clustering solutions, it is a challenging task
to obtain an ensemble of these solutions. This becomes more challenging when
the ground truth about the number of clusters is unavailable. In this paper, we
introduce a crowd-powered model to collect solutions of image clustering from
the general crowd and pose it as a clustering ensemble problem with variable
number of clusters. The varying number of clusters basically reflects the crowd
workers' perspective toward a particular set of objects. We allow a set of
crowd workers to independently cluster the images as per their perceptions. We
address the problem by finding out centroid of the clusters using an
appropriate distance measure and prioritize the likelihood of similarity of the
individual cluster sets. The effectiveness of the proposed method is
demonstrated by applying it on multiple artificial datasets obtained from
crowd.


title:
ARPES study of the epitaxially grown topological crystalline insulator
  SnTe(111)

abstract:
  SnTe is a prototypical topological crystalline insulator, in which the
gapless surface state is protected by a crystal symmetry. The hallmark of the
topological properties in SnTe is the Dirac cones projected to the surfaces
with mirror symmetry, stemming from the band inversion near the L points of its
bulk Brillouin zone, which can be measured by angle-resolved photoemission. We
have obtained the (111) surface of SnTe film by molecular beam epitaxy on
BaF2(111) substrate. Photon-energy-dependence of in situ angle-resolved
photoemission, covering multiple Brillouin zones in the direction perpendicular
tothe (111) surface, demonstrate the projected Dirac cones at the Gamma_bar and
M_bar points of the surface Brillouinzone. In addition, we observe a
Dirac-cone-like band structure at the Gamma point of the bulk Brillouin
zone,whose Dirac energy is largely different from those at the Gamma_bar and
M_bar points.


title:
Pattern formation on the free surface of a ferrofluid: spatial dynamics
  and homoclinic bifurcation

abstract:
  We establish the existence of spatially localised one-dimensional free
surfaces of a ferrofluid near onset of the Rosensweig instability, assuming a
general (nonlinear) magnetisation law. It is shown that the ferrohydrostatic
equations can be derived from a variational principle that allows one to
formulate them as an (infinite-dimensional) spatial Hamiltonian system in which
the unbounded free-surface direction plays the role of time. A centre-manifold
reduction technique converts the problem for small solutions near onset to an
equivalent Hamiltonian system with finitely many degrees of freedom.
Normal-form theory yields the existence of homoclinic solutions to the reduced
system, which correspond to spatially localised solutions of the
ferrohydrostatic equations.


title: The Iwasawa Algebra $\Omega_G$ and Its Dual Artin Coalgebra

abstract:
  For any compact $p$-adic Lie group $G$, the Iwasawa algebra $\Omega_G$ over
finite field $\mathbb{F}_p$ is a complete noetherian semilocal algebra. It is
shown that $\Omega_G$ is the dual algebra of an artinian coalgebra $C$. We
induce a duality between the derived category
$\mathcal{D}^b_{fg}(_{\Omega_G}\mathcal{M})$ of bounded complexes of left
$\Omega_G$-modules with finitely generated cohomology modules and the derived
category $\mathcal{D}^b_{qf}(^C\mathcal{M})$ of bounded complexes of left
$C$-comodules with quasi-finite cohomology comodules.


title: On Coron's problem for weakly coupled elliptic systems

abstract:
  We consider the following critical weakly coupled elliptic system \[
\begin{cases} -\Delta u_i = \mu_i |u_i|^{2^*-2}u_i + \sum_{j \neq i} \beta_{ij}
|u_j|^{\frac{2^*}{2}} |u_i|^{\frac{2^*-4}{2}} u_i & \text{in
$\Omega_\varepsilon$} u_i >0 & \text{in $\Omega_\varepsilon$} u_i = 0 &
\text{on $\partial \Omega_\varepsilon$},\end{cases} \qquad i =1,\dots,m, \] in
a domain $\Omega_\varepsilon \subset \mathbb{R}^N$, $N=3,4$, with small
shrinking holes as the parameter $\varepsilon \to 0$. We prove the existence of
positive solutions of two different types: either each density concentrates
around a different hole, or we have groups of components such that all the
components within a single group concentrate around the same point, and
different groups concentrate around different points.


title:
Activation cross sections of proton and deuteron induced nuclear
  reactions on holmium and erbium, related to the production of $^{161}$Er and
  $^{160}$Er medical isotopes

abstract:
  Experimental excitation functions for long-lived products in proton induced
reactions were measured with the activation method in the 37-65 MeV energy
range on natural holmium. Stacked foil irradiation technique and high
resolution gamma spectrometry were used in order to measure cross-section data
for the production of $^{161}$Er, $^{160}$Er and $^{159,157}$Dy. For comparison
of the production routes of medically related $^{161}$Er and $^{160}$Er
radioisotopes new experimental cross section data were deduced for the
$^{162}$Er(p,x)$^{161,160}$Er and $^{162}$Er(d,x)$^{161,160}$Er reactions by
re-evaluating gamma-ray spectra from earlier measurements. No earlier data were
found in the literature for these reactions. The experimental data are compared
with results of TALYS theoretical code reported in TENDL-2015.


title:
Note on non-vacuum conformal family contributions to R\'enyi entropy in
  two-dimensional CFT

abstract:
  We calculate the contributions of a general non-vacuum conformal family to
R\'enyi entropy in two-dimensional conformal field theory (CFT). The primary
operator of the conformal family can be either non-chiral or chiral, and we
denote its scaling dimension by $\Delta$. For the case of two short intervals
on complex plane, we expand the R\'enyi mutual information by the cross ratio
$x$ to order $x^{2\Delta+2}$. For the case of one interval on torus with the
temperature being low, we expand the R\'enyi entropy by $q=\exp(-2\pi\beta/L)$,
with $\beta$ being the inverse temperature and $L$ being the spatial period, to
order $q^{\Delta+2}$. To make the result meaningful, we require that the
scaling dimension $\Delta$ cannot be too small. For two intervals on complex
plane we need $\Delta>1$, and for one interval on torus we need $\Delta>2$. We
work in small Newton constant limit in gravity side and so large central charge
limit in CFT side, and find matches of gravity and CFT results.


title: Invariance principle for `push' tagged particles for a Toom Interface

abstract:
  In many interacting particle systems, tagged particles move diffusively upon
subtracting a drift. General techniques to prove such `invariance principles'
are available for reversible processes (Kipnis-Varadhan) and for non-reversible
processes in dimension $d>2$. The interest of our paper is that it considers a
non-reversible one-dimensional process: the Toom model. The reason that we can
prove the invariance principle is that in this model, push-tagged particles
move manifestly slower than second-class particles.


title: Hardness of approximation for strip packing

abstract:
  Strip packing is a classical packing problem, where the goal is to pack a set
of rectangular objects into a strip of a given width, while minimizing the
total height of the packing. The problem has multiple applications, e.g. in
scheduling and stock-cutting, and has been studied extensively.
  When the dimensions of objects are allowed to be exponential in the total
input size, it is known that the problem cannot be approximated within a factor
better than $3/2$, unless $\mathrm{P}=\mathrm{NP}$. However, there was no
corresponding lower bound for polynomially bounded input data. In fact,
Nadiradze and Wiese [SODA 2016] have recently proposed a $(1.4 + \epsilon)$
approximation algorithm for this variant, thus showing that strip packing with
polynomially bounded data can be approximated better than when exponentially
large values in the input data are allowed. Their result has subsequently been
improved to a $(4/3 + \epsilon)$ approximation by two independent research
groups [FSTTCS 2016, arXiv:1610.04430]. This raises a question whether strip
packing with polynomially bounded input data admits a quasi-polynomial time
approximation scheme, as is the case for related two-dimensional packing
problems like maximum independent set of rectangles or two-dimensional
knapsack.
  In this paper we answer this question in negative by proving that it is
NP-hard to approximate strip packing within a factor better than $12/11$, even
when admitting only polynomially bounded input data. In particular, this shows
that the strip packing problem admits no quasi-polynomial time approximation
scheme, unless $\mathrm{NP} \subseteq \mathrm{DTIME}(2^{\mathrm{polylog}(n)})$.


title:
Improved liver T1rho measurement precision with a breathhold black blood
  single shot fast spin echo acquisition: a validation study in healthy
  volunteers

abstract:
  Purpose: To explore the usability and normal T1rho value of liver parenchyma
with a novel single breathhold black blood single shot fast spin echo
acquisition based liver imaging sequence. Materials and Methods: In total 19
health subjects (10 males, 9 females; mean age: 37.4 yrs; range: 23-54 yrs)
participated in the study. 11 subjects had liver scanned twice in the same
session to access scan-rescan repeatability. 12 subjects had liver scanned
twice in two sessions with 7-10 days' interval to access scan-rescan
reproducibility. MR was performed with a 3.0 T scanner with dual transmitter.
The MR sequence allows simultaneous acquisition of 4 spin lock times (TSLs:
0ms, 10 ms, 30 ms, 50ms) in 10 second. Inherent black blood effect of fast spin
echo and double inversion recovery were utilized to achieve blood signal
suppression. Results: The technique demonstrated good image quality and minimal
artifacts. For liver parenchyma, Bland-Altman plot showed the scan-rescan
repeatability mean difference was 0.025 ms (95% limits of agreement: -1.163 to
1.213 ms), and intraclass correlation coefficient (ICC) was 0.977. The
scan-rescan reproducibility mean difference was -0.075 ms (95% limits of
agreement: -3.280 to 3.310 ms), and ICC was 0.820 which is better than the ICC
of 0.764 of a previous bright blood multi-breath hold gradient echo acquisition
technique. The liver T1rho value was 39.9 +/- 2.4 ms (range: 36.1 - 44.2 ms),
which is lower than the value of 42.8=/-2.1 ms acquired with the previous
bright blood technique. Conclusion: This study validated the application of a
single breathhold black blood single shot fast spin echo acquisition based for
human liver T1rho imaging. The lower liver parenchyma T1rho value and higher
scan rescan reproducibility may improve of the sensitivity of this technique.


title: Levi Problem in Complex Manifolds

abstract:
  Let U be a pseudoconvex open set in a complex manifold M. When is U a Stein
manifold? There are classical counter examples due to Grauert, even when U has
real-analytic boundary or has strictly pseudoconvex points. We give new
criteria for the Steinness of U and we analyze the obstructions. The main tool
is the notion of Levi-currents. They are positive $\ddbar$-closed currents T of
bidimension (1,1) and of mass 1 directed by the directions where all continuous
psh functions in $U$ have vanishing Levi-form. The extremal ones, are supported
on the sets where all continuous psh functions are constant. We also construct
under geometric conditions, bounded strictly psh exhaustion functions, and
hence we obtain Donnelly- Fefferman weights. To any infinitesimally homogeneous
manifold, we associate a foliation. The dynamics of the foliation determines
the solution of the Levi-problem. Some of the results can be extended to the
context of pseudoconvexity with respect to a Pfaff-system.


title:
Bi-phase age-related brain gray matter magnetic resonance T1rho
  relaxation time change

abstract:
  Objectives: To investigate normative value and age-related change of brain
magnetic resonance T1rho relaxation at 1.5 T. Methods: 20 males (age:
40.7+/-15.5 years, range: 22-68 years) and 22 females (age: 38.5 +/-14.8 years,
range: 21-62 years), were scanned at 1.5 Tesla using 3D fluid suppressed turbo
spin echo sequence. Regions-of-interests (ROIs) were obtained by atlas-based
tissue segmentation and T1rho was calculated by fitting the mean value to
monoexponential model. Correlation between T1rho relaxation of brain gray
matter regions and age was investigated. Results: A regional difference among
individual gray matter areas was noted; with hippocampus (98.37+/-5.37 msec)
and amygdala (94.95+/-4.34 msec) have the highest measurement, while pallidum
(83.81+/-5.49) and putamen (83.93+4.76) the lowest measurement. T1rho values
decreased slowly (mean slope: -0.256) and significantly (p<0.05) with age in
gray matter for subjects younger than 40 years old, while for subjects older
than 40 years old there was no significant correlation between T1rho relaxation
and age. Conclusion: T1rho relaxation demonstrates a bi-phase change with age
in adults of 22-68 years.


title:
Online Submodular Maximization with Free Disposal: Randomization Beats
  0.25 for Partition Matroids

abstract:
  We study the online submodular maximization problem with free disposal under
a matroid constraint. Elements from some ground set arrive one by one in
rounds, and the algorithm maintains a feasible set that is independent in the
underlying matroid. In each round when a new element arrives, the algorithm may
accept the new element into its feasible set and possibly remove elements from
it, provided that the resulting set is still independent. The goal is to
maximize the value of the final feasible set under some monotone submodular
function, to which the algorithm has oracle access.
  For $k$-uniform matroids, we give a deterministic algorithm with competitive
ratio at least $0.2959$, and the ratio approaches $\frac{1}{\alpha_\infty}
\approx 0.3178$ as $k$ approaches infinity, improving the previous best ratio
of $0.25$ by Chakrabarti and Kale (IPCO 2014), Buchbinder et al. (SODA 2015)
and Chekuri et al. (ICALP 2015). We also show that our algorithm is optimal
among a class of deterministic monotone algorithms that accept a new arriving
element only if the objective is strictly increased.
  Further, we prove that no deterministic monotone algorithm can be strictly
better than $0.25$-competitive even for partition matroids, the most modest
generalization of $k$-uniform matroids, matching the competitive ratio by
Chakrabarti and Kale (IPCO 2014) and Chekuri et al. (ICALP 2015).
Interestingly, we show that randomized algorithms are strictly more powerful by
giving a (non-monotone) randomized algorithm for partition matroids with ratio
$\frac{1}{\alpha_\infty} \approx 0.3178$.


title:
Omnidirectional Space-Time Block Coding for Common Information
  Broadcasting in Massive MIMO Systems

abstract:
  In this paper, we design space-time block codes (STBCs) to broadcast the
common information omnidirectionally in a massive MIMO downlink. To reduce the
burden of the downlink channel estimation and achieve partial spatial diversity
from base station (BS) transmit antennas, we propose channel-independently
precoded low-dimensional STBC. The precoding matrix and the signal
constellation in the low-dimensional STBC are jointly designed to guarantee
omnidirectional coverage at any instant time and sufficiently utilize the power
amplifier capacities of BS transmit antennas, and at the same time, achieve the
full diversity of the low-dimensional STBC. Under this framework, several
designs are presented. To provide transmit diversity order of two, a precoded
Alamouti code is proposed, which has a fast symbol-wise maximum-likelihood (ML)
decoding. To provide transmit diversity order of four, three types of STBCs are
proposed, being referred to as precoded orthogonal STBC (OSTBC), precoded
quasi-orthogonal STBC (QOSTBC), and precoded coordinate interleaved orthogonal
design (CIOD), respectively. The last two codes have the same complexity for
pair-wise ML decoding, while precoded QOSTBC has a higher coding gain when the
bit rate is lower than or equal to 4 bps/Hz, and precoded CIOD has a higher
coding gain when the bit rate is higher than 4 bps/Hz. Precoded OSTBC has a
higher decoding complexity and a lower coding gain than the other two codes,
since in the precoded OSTBC the information symbols need to be jointly designed
and decoded. Moreover, a precoded no-zero-entry Toeplitz code and a precoded
no-zero-entry overlapped Alamouti code are also proposed. These two codes can
achieve a higher diversity order with linear receivers.


title:
Visual Themes and Sentiment on Social Networks To Aid First Responders
  During Crisis Events

abstract:
  Online Social Networks explode with activity whenever a crisis event takes
place. Most content generated as part of this activity is a mixture of text and
images, and is particularly useful for first responders to identify popular
topics of interest and gauge the pulse and sentiment of citizens. While
multiple researchers have used text to identify, analyze and measure themes and
public sentiment during such events, little work has explored visual themes
floating on networks in the form of images, and the sentiment inspired by them.
Given the potential of visual content for influencing users' thoughts and
emotions, we perform a large scale analysis to compare popular themes and
sentiment across images and textual content posted on Facebook during the
terror attacks that took place in Paris in 2015. Using state-of-the-art image
summarization techniques, we discovered multiple visual themes which were
popular in images, but were not identifiable through text. We uncovered
instances of misinformation and false flag (conspiracy) theories among popular
image themes, which were not prominent in user generated textual content, and
can be of particular inter- est to first responders. Our analysis also revealed
that while textual content posted after the attacks reflected negative
sentiment, images inspired positive sentiment. To the best of our knowledge,
this is the first large scale study of images posted on social networks during
a crisis event.


title:
Tan's contact of a harmonically trapped one-dimensional Bose gas:
  strong-coupling expansion and conjectural approach at arbitrary interactions

abstract:
  We study Tan's contact, i.e. the coefficient of the high-momentum tails of
the momentum distribution at leading order, for an interacting one-dimensional
Bose gas subjected to a harmonic confinement. Using a strong-coupling
systematic expansion of the ground-state energy of the homogeneous system
stemming from the Bethe-Ansatz solution, together with the local-density
approximation, we obtain the strong-coupling expansion for Tan's contact of the
harmonically trapped gas. Also, we use a very accurate conjecture for the
ground-state energy of the homogeneous system to obtain an approximate
expression for Tan's contact for arbitrary interaction strength, thus
estimating the accuracy of the strong-coupling expansion. Our results are
relevant for ongoing experiments with ultracold atomic gases.


title: Bursts of activity in collective cell migration

abstract:
  Dense monolayers of living cells display intriguing relaxation dynamics,
reminiscent of soft and glassy materials close to the jamming transition, and
migrate collectively when space is available, as in wound healing or in cancer
invasion. Here we show that collective cell migration occurs in bursts that are
similar to those recorded in the propagation of cracks, fluid fronts in porous
media and ferromagnetic domain walls. In analogy with these systems, the
distribution of activity bursts displays scaling laws that are universal in
different cell types and for cells moving on different substrates. The main
features of the invasion dynamics are quantitatively captured by a model of
interacting active particles moving in a disordered landscape. Our results
illustrate that collective motion of living cells is analogous to the
corresponding dynamics in driven, but inanimate, systems.


title: Complex and Kahler structures on hom-Lie algebras

abstract:
  Complex and Hermitian structures on hom-Lie algebras are introduced and some
examples of these structures are presented. Also, it is shown that there not
exists a proper complex (Hermitian) home-Lie algebra of dimension two. Then
using a hom-left symmetric algebra, a phase space is provided and then a
complex structure on it, is presented. Finally, the notion of Kahler hom-Lie
algebra is introduced and then using a Kahler hom-Lie algebra, a phase space is
constructed.


title: On a restricted linear congruence

abstract:
  Let $b,n\in \mathbb{Z}$, $n\geq 1$, and ${\cal D}_1, \ldots, {\cal
D}_{\tau(n)}$ be all positive divisors of $n$. For $1\leq l \leq \tau(n)$,
define ${\cal C}_l:=\lbrace 1 \leqslant x\leqslant n \; : \; (x,n)={\cal
D}_l\rbrace$. In this paper, by combining ideas from the finite Fourier
transform of arithmetic functions and Ramanujan sums, we give a short proof for
the following result: the number of solutions of the linear congruence
$x_1+\cdots +x_k\equiv b \pmod{n}$, with $\kappa_{l}=|\lbrace x_1, \ldots, x_k
\rbrace \cap {\cal C}_l|$, $1\leq l \leq \tau(n)$, is \begin{align*}
\frac{1}{n}\mathlarger{\sum}_{d\, \mid \,
n}c_{d}(b)\mathlarger{\prod}_{l=1}^{\tau(n)}\left(c_{\frac{n}{{\cal
D}_l}}(d)\right)^{\kappa_{l}}, \end{align*} where $c_{d}(b)$ is a Ramanujan
sum. Some special cases and other forms of this problem have been already
studied by several authors. The problem has recently found very interesting
applications in number theory, combinatorics, computer science, and
cryptography. The above explicit formula generalizes the main results of
several papers, for example, the main result of the paper by Sander and Sander
[J. Number Theory {\bf 133} (2013), 705--718], one of the main results of the
paper by Sander [J. Number Theory {\bf 129} (2009), 2260--2266], and also gives
an equivalent formula for the main result of the paper by Sun and Yang [Int. J.
Number Theory {\bf 10} (2014), 1355--1363].


title: Dynamical Casimir Effect for Gaussian Boson Sampling

abstract:
  We show that the Dynamical Casimir Effect (DCE), realized on two multimode
coplanar waveguide resonators, implements a gaussian boson sampler (GBS). The
appropriate choice of the mirror acceleration that couples both resonators
translates into the desired initial gaussian state and many-boson interference
in a boson sampling network. In particular, we show that the proposed quantum
simulator naturally performs a classically hard task, known as scattershot
boson sampling. Our result unveils an unprecedented computational power of DCE,
and paves the way for using DCE as a resource for quantum simulation.


title: Subexponential parameterized algorithms for graphs of polynomial growth

abstract:
  We show that for a number of parameterized problems for which only $2^{O(k)}
n^{O(1)}$ time algorithms are known on general graphs, subexponential
parameterized algorithms with running time $2^{O(k^{1-\frac{1}{1+\delta}}
\log^2 k)} n^{O(1)}$ are possible for graphs of polynomial growth with growth
rate (degree) $\delta$, that is, if we assume that every ball of radius $r$
contains only $O(r^\delta)$ vertices. The algorithms use the technique of
low-treewidth pattern covering, introduced by Fomin et al. [FOCS 2016] for
planar graphs; here we show how this strategy can be made to work for graphs
with polynomial growth.
  Formally, we prove that, given a graph $G$ of polynomial growth with growth
rate $\delta$ and an integer $k$, one can in randomized polynomial time find a
subset $A \subseteq V(G)$ such that on one hand the treewidth of $G[A]$ is
$O(k^{1-\frac{1}{1+\delta}} \log k)$, and on the other hand for every set $X
\subseteq V(G)$ of size at most $k$, the probability that $X \subseteq A$ is
$2^{-O(k^{1-\frac{1}{1+\delta}} \log^2 k)}$. Together with standard dynamic
programming techniques on graphs of bounded treewidth, this statement gives
subexponential parameterized algorithms for a number of subgraph search
problems, such as Long Path or Steiner Tree, in graphs of polynomial growth.
  We complement the algorithm with an almost tight lower bound for Long Path:
unless the Exponential Time Hypothesis fails, no parameterized algorithm with
running time $2^{k^{1-\frac{1}{\delta}-\varepsilon}}n^{O(1)}$ is possible for
any $\varepsilon > 0$ and an integer $\delta \geq 3$.


title:
Accelerating Hartree--Fock exchange calculation using the TURBOMOLE
  program system: different techniques for different purposes

abstract:
  Hartree--Fock theory is one of the most ancient methods of computational
chemistry, but up to the present day quantum chemical calculations on
Hartree--Fock level or with hybrid density functional theory can be excessively
time consuming.
  We compare three currently available techniques to reduce the computational
demands of such calculations in terms of timing and accuracy.


title:
Visualization of unidirectional optical waveguide using topological
  photonic crystals made of dielectric material

abstract:
  The introduction of topology unravels a new chapter of physics. Topological
systems provide unique edge/interfacial quantum states which are expected to
contribute to the development of novel spintronics and open the door to robust
quantum computation. Optical systems can also benefit from topology.
Engineering locally in real space a honeycomb photonic crystal with double
Dirac cone in its photonic dispersion, topology transition in photonic band
structure is induced and a pseudospin unidirectional optical channel is created
and demonstrated by the backscattering immune electromagnetic transportation.
The topological photonic crystal made of dielectric material can pave the road
towards steering light propagations and contribute to novel communication
technology.


title: Affine Periplectic Brauer Algebras

abstract:
  We formulate Nazarov-Wenzl type algebras ${\widehat{P}_d^-}$ for the
representation theory of the Periplectic Lie superalgebras $\mathfrak{p}(n)$.
We establish a Arakawa-Suzuki type theorem to provide a connection between
$\mathfrak{p}(n)$-representations and $\widehat{P}_d^-$-representations. We
also consider various tensor product representations for $\widehat{P}_d^-$. The
periplectic Brauer algebra $A_d$ defined by Moon is an quotient of
$\widehat{P}_d^-$. In particular, actions induced by Jucys-Murphy elements can
be obtained under the tensor product representation of $\widehat{P}_d^-$. Also,
a Poincare-Birkhoff-Witt type basis for $\widehat{P}_d^-$ is obtained.


title: Milne's correcting factor and derived de Rham cohomology II

abstract:
  Milne's correcting factor, which appears in the Zeta-value at $s=n$ of a
smooth projective variety $X$ over a finite field $\mathbb{F}_q$, is the Euler
characteristic of the derived de Rham cohomology of $X/\mathbb{Z}$ modulo the
Hodge filtration $F^n$. In this note, we extend this result to arbitrary
separated schemes of finite type over $\mathbb{F}_q$ of dimension at most $d$,
provided resolution of singularities for schemes of dimension at most $d$
holds. More precisely, we show that Geisser's generalization of Milne's factor,
whenever it is well defined, is the Euler characteristic of the $eh$-cohomology
with compact support of the derived de Rham complex relative to $\mathbb{Z}$
modulo $F^n$.


title: GMRT observations of IC 711 -- The longest head-tail radio galaxy known

abstract:
  We present low-frequency, GMRT observations at 240, 610 and 1300 MHz of
IC~711, a narrow angle tail (NAT) radio galaxy. The total angular extent of the
radio emission, $\sim 22$ arcmin, corresponds to a projected linear size of
$\sim 900$ kpc, making it the longest among the known head-tail radio galaxies.
The objectives of the GMRT observations were to investigate the radio
morphology, especially of the long tail structure, at low frequencies. The
radio structure, especially initial $\sim 10$ arcmin of tail being a long
straight feature, does not seem to be consistent with a simple circular motion
around the cluster centre, as previously suggested in the literature. Two sharp
bends after the straight section of the tail cast doubt on the prevailing idea
in the literature that the long narrow tails represent trails left behind by
the fast moving parent optical galaxy with respect to the cluster medium, as
the optical galaxy could not have undergone such sharp bends in its path, under
any conceivable gravitational influence of some individual galaxy or of the
overall cluster gravitational potential. In fact the tail does not seem to have
been influenced by the gravitational field of any of the cluster-member
galaxies. The radio spectrum of the head, coinciding with the optical galaxy,
is flat ($\alpha \stackrel{<}{_{\sim}}0.4$ for $S \propto \nu ^{-\alpha}$), but
steadily steepens along the radio tail, with the end part of the tail showing
the steepest spectrum ($\alpha \, {\sim}$ 4 -- 5) ever seen in any diffuse
radio emission region.


title: Robustness of flight leadership relations in pigeons

abstract:
  Collective animal movements produce spectacular natural phenomena that arise
from simple local interactions among group members. Flocks of homing pigeons,
Columba livia, provide a useful model for the study of collective motion and
decision making. During homing flights, flock members are forced to resolve
potentially divergent navigational preferences in order to stay together and
benefit from flying in a group. Recent work has demonstrated that some
individuals consistently contribute more to the movement decisions of the flock
than others do, thereby generating stable hierarchical leader/follower
networks. Yet, what attributes of a flying pigeon reliably predict leadership
remains an open question. We examined the flexibility of an individual's
hierarchical leadership rank (i.e. its ordinal position when flock members are
ranked according to the average time differences with which they lead or follow
others) as a function of changes in its navigational knowledge. We manipulated
already established hierarchical networks in three different flocks, by
providing certain individuals with additional homing experience. We found that
such training did not consistently lead to an increase in birds' leadership
ranks, and that, in general, the nature of leader/follower interactions between
trained and untrained birds remained unaffected. Thus, leadership hierarchies
in pigeon flocks appear resistant to changes in the navigational knowledge of a
subset of their members, at least when these changes are relatively small. We
discuss the implications of our results in light of the potential benefits of
structural stability in decision-making networks.


title:
Reconstruction of real-space linear matter power spectrum from
  multipoles of BOSS DR12 results

abstract:
  Recently, the power spectrum (PS) multipoles using the Baryon Oscillation
Spectroscopic Survey (BOSS) Data Release 12 (DR12) sample are analyzed
\cite{160703150}. The based model for the analysis is the so-called TNS
quasi-linear model and the analysis provides the multipoles up to the
hexadecapole \cite{TNS}. Thus, one might be able to recover the real-space
linear matter PS by using the combinations of multipoles to investigate the
cosmology \cite{0407214}. We provide the analytic form of the ratio of
quadrupole (hexadecapole) to monopole moments of the quasi-linear PS including
the Fingers-of-God (FoG) effect to recover the real-space PS in the linear
regime. One expects that observed values of the ratios of multipoles should be
consistent with those of the linear theory at large scales. Thus, we compare
the ratios of multipoles of the linear theory, including the FoG effect with
the measured values. From these, we recover the linear matter power spectra in
real-space. These recovered power spectra are consistent with the linear matter
power spectra.


title:
Delineating the role of ripples on thermal expansion of honeycomb
  materials:graphene, 2D-h-BN and monolayer(ML)-MoS2

abstract:
  We delineated the role of thermally excited ripples on thermal expansion
properties of 2D honeycomb materials (free-standing graphene, 2D h-BN, and
ML-MoS2), by explicitly carrying out three-dimensional (3D) and two-dimensional
(2D) molecular dynamics simulations. In 3D simulations, the in-plane lattice
parameter (a-lattice) of graphene and 2D h-BN shows thermal contraction over a
wide range of temperatures and exhibits a strong system size dependence. The 2D
simulations of the very same system show a reverse trend, where the a-lattice
is expanding in the whole computed temperature range. Contrary to graphene and
2D h-BN, the a-lattice of ML-MoS2 shows thermal expansion in both 2D and 3D
simulations and their system size dependence is marginal. By analyzing the
phonon dispersion at 300 K, we found that the discrepancy between 2D and 3D
simulations of graphene and 2D h-BN is due to the absence of out-of-plane
bending mode (ZA) in 2D simulations, which is responsible for thermal
contraction of a-lattice at low temperature. Meanwhile, all the phonon modes
are present in 2D phonon dispersion of ML-MoS2, which indicates that the origin
of ZA mode is not purely due to out-of-plane movement of atoms and also its
effect on thermal expansion is not significant as found in graphene and 2D h-BN


title:
In-medium dispersion relations of charmonia studied by maximum entropy
  method

abstract:
  We study in-medium spectral properties of charmonia in the vector and
pseudoscalar channels at nonzero momenta on quenched lattices, especially
focusing on their dispersion relation and weight of the peak. We measure the
lattice Euclidean correlation functions with nonzero momenta on the anisotropic
quenched lattices and study the spectral functions with the maximum entropy
method. The dispersion relations of charmonia and the momentum dependence of
the weight of the peak are analyzed with the maximum entropy method together
with the errors estimated probabilistically in this method. We find significant
increase of the masses of charmonia in medium. It is also found that the
functional form of the charmonium dispersion relations is not changed from that
in the vacuum within the error even at $T\simeq1.6T_c$ for all the channels we
analyzed.


title:
Considerations on the thermal equilibrium between matter and the cosmic
  horizon

abstract:
  A common feature in the thermodynamic analysis of homogeneous and isotropic
world models is the assumption that the temperature of the fluids inside the
cosmic horizon (including dark energy) coincides with the temperature of the
latter, whether it be either the event or the apparent horizon. We examine up
to what extent this assumption may be justified, given that these temperatures
evolve under different time-temperature laws. We argue that while radiation
cannot reach thermal equilibrium with the horizon, non-relativistic matter may,
and dark energy might though only approximately.


title: MIMO Systems With Low-Resolution ADCs: Linear Coding Approach

abstract:
  This paper considers a multiple-input multiple-output (MIMO) system with
low-resolution analog-to-digital converters (ADCs). In this system, the paper
presents a new MIMO detection approach using coding theory. The principal idea
of the proposed approach is to transform a non-linear MIMO channel to a linear
MIMO channel by leveraging both a $p$-level quantizer and a lattice code where
$p\geq 2$. After transforming to the linear MIMO channel with the sets of
finite input and output elements, efficient MIMO detection methods are proposed
to attain both diversity and multiplexing gains by using algebraic coding
theory. In particular, using the proposed methods, the analytical
characterizations of achievable rates are derived for different MIMO
configurations. One major observation is that the proposed approach is
particularly useful for a large MIMO system with the ADCs that use a few bits.


title: On SL(2;R) symmetry in nonlinear electrodynamics theories

abstract:
  Recently, it has been observed that the Noether-Gaillard-Zumino (NGZ)
identity holds order by order in $\alpha'$ expansion in nonlinear
electrodynamics theories as Born-Infeld (BI) and Bossard-Nicolai (BN). The
nonlinear electrodynamics theory that couples to an axion field is invariant
under the $SL(2,R)$ duality in all orders of $\alpha'$ expansion in the
Einstein frame. In this paper we show that there are the $SL(2,R)$ invariant
forms of the energy momentum tensors of axion-nonlinear electrodynamics
theories in the Einstein frame. These $SL(2,R)$ invariant structures appear in
the energy momentum tensors of BI and BN theories at all orders of $\alpha'$
expansion. The $SL(2,R)$ symmetry appears in the BI and BN Lagrangians as a
multiplication of Maxwell Lagrangian and a series of $SL(2,R)$ invariant
structures.


title:
Contracting isometries of CAT(0) cube complexes and acylindrical
  hyperbolicity of diagram groups

abstract:
  The main technical result of this paper is to characterize the contracting
isometries of a CAT(0) cube complex without any assumption on its local
finiteness. Afterwards, we introduce the combinatorial boundary of a CAT(0)
cube complex, and we show that contracting isometries are strongly related to
isolated points at infinity, when the complex is locally finite. This boundary
turns out to appear naturally in the context of Guba and Sapir's diagram
groups, and we apply our main criterion to determine precisely when an element
of a diagram group induces a contracting isometry on the associated Farley cube
complex. As a consequence, in some specific case, we are able to deduce a
criterion to determine precisely when a diagram group is acylindrically
hyperbolic.


title:
Interlayer current near the edge of an InAs/GaSb double quantum well in
  proximity with a superconductor

abstract:
  We investigate charge transport through the junction between a niobium
superconductor and the edge of a two-dimensional electron-hole bilayer,
realized in an InAs/GaSb double quantum well. For the transparent interface
with a superconductor, we demonstrate that the junction resistance is
determined by the interlayer charge transfer near the interface. From an
analysis of experimental $I-V$ curves we conclude that the proximity induced
superconductivity efficiently couples electron and hole layers at low currents.
The critical current demonstrates periodic dependence on the in-plane magnetic
field, while it is monotonous for the field which is normal to the bilayer
plane.


title:
Complete determination of the zeta function of the Hilbert scheme of $n$
  points on a two-dimensional torus

abstract:
  We compute the coefficients of the polynomials $C_n(q)$ defined by the
equation \begin{equation*} 1 + \sum_{n\geq 1} \, \frac{C_n(q)}{q^n} \, t^n =
\prod_{i\geq 1}\, \frac{(1-t^i)^2}{1-(q+q^{-1})t^i + t^{2i}} \, .
\end{equation*} As an application we obtain an explicit formula for the zeta
function of the Hilbert scheme of $n$ points on a two-dimensional torus and
show that this zeta function satisfies a remarkable functional equation. The
polynomials $C_n(q)$ are divisible by $(q-1)^2$. We also compute the
coefficients of the polynomials $P_n(q) = C_n(q)/(q-1)^2$: each coefficient
counts the divisors of $n$ in a certain interval; it is thus a non-negative
integer. Finally we give arithmetical interpretations for the values of
$C_n(q)$ and of $P_n(q)$ at $q = -1$ and at roots of unity of order $3$, $4$,
$6$.


title:
On the non-vanishing of theta liftings of tempered representations of
  U(p,q)

abstract:
  In this paper, we give an explicit determination of the non-vanishing of the
theta liftings for unitary dual pairs (U(p,q), U(r,s)). Assuming the local
Gan-Gross-Prasad conjecture, we determine when theta lifts of tempered
representations are nonzero in terms of the local Langlands correspondence.


title: Heavy Higgs boson resonances and their decay into top quarks at the LHC

abstract:
  We investigate, within the type-II two-Higgs-doublet extension of the
standard model (SM), the impact of heavy neutral Higgs boson resonances with
unsuppressed Yukawa couplings to top quarks on top-quark pair production at the
LHC at next-to-leading order (NLO) in the strong coupling constant. We take
into account the resonant Higgs boson contributions, the non-resonant SM
$t\bar{t}$ continuum and the interference of these two contributions. The NLO
QCD corrections to heavy Higgs production and the interference contributions
are calculated in the large top-quark mass ($m_t$) limit, including an
effective K-factor rescaling. Our evaluation of the QCD-Higgs interference is
focused on the Higgs resonance region. Using representative CP-conserving as
well as CP-violating parameter scenarios phenomenological results are presented
for different observables.


title:
Still not there? Comparing Traditional Sequence-to-Sequence Models to
  Encoder-Decoder Neural Networks on Monotone String Translation Tasks

abstract:
  We analyze the performance of encoder-decoder neural models and compare them
with well-known established methods. The latter represent different classes of
traditional approaches that are applied to the monotone sequence-to-sequence
tasks OCR post-correction, spelling correction, grapheme-to-phoneme conversion,
and lemmatization. Such tasks are of practical relevance for various
higher-level research fields including digital humanities, automatic text
correction, and speech recognition. We investigate how well generic
deep-learning approaches adapt to these tasks, and how they perform in
comparison with established and more specialized methods, including our own
adaptation of pruned CRFs.


title: Frank-Wolfe Algorithms for Saddle Point Problems

abstract:
  We extend the Frank-Wolfe (FW) optimization algorithm to solve constrained
smooth convex-concave saddle point (SP) problems. Remarkably, the method only
requires access to linear minimization oracles. Leveraging recent advances in
FW optimization, we provide the first proof of convergence of a FW-type saddle
point solver over polytopes, thereby partially answering a 30 year-old
conjecture. We also survey other convergence results and highlight gaps in the
theoretical underpinnings of FW-style algorithms. Motivating applications
without known efficient alternatives are explored through structured prediction
with combinatorial penalties as well as games over matching polytopes involving
an exponential number of constraints.


title: Hybrid Airy Plasmons with Dynamically Steerable Trajectories

abstract:
  With the intriguing properties of diffraction-free, self-accelerating, and
self-healing, Airy plasmons are promising to be used in the trapping,
transporting, and sorting of micro-objects, imaging, and chip scale signal
processing. However, the high dissipative loss and the lack of dynamical
steerability restrict the implementation of Airy plasmons in these
applications. Here we reveal the hybrid Airy plasmons for the first time by
taking a hybrid graphene-based plasmonic waveguide in the terahertz (THz)
domain as an example. Due to the coupling between an optical mode and a
plasmonic mode, the hybrid Airy plasmons can have large propagation lengths and
effective transverse deflections, where the transverse waveguide confinements
are governed by the hybrid modes with moderate quality factors. Meanwhile, the
propagation trajectories of hybrid Airy plasmons are dynamically steerable by
changing the chemical potential of graphene. These hybrid Airy plasmons may
promote the further discovery of non-diffracting beams with the emerging
developments of optical tweezers and tractor beams.


title: A propelling neutron star in the enigmatic Be-star $\gamma$~Cassiopeia

abstract:
  The enigmatic X-ray emission from the bright optical star, $\gamma$
Cassiopeia, is a long-standing problem. $\gamma$ Cas is known to be a binary
system consisting of a Be-type star and a low-mass ($M\sim 1\,M_\odot$)
companion of unknown nature orbiting in the Be-disk plane. Here we apply the
quasi-spherical accretion theory onto a compact magnetized star and show that
if the low-mass companion of $\gamma$ Cas is a fast spinning neutron star, the
key observational signatures of $\gamma$ Cas are remarkably well reproduced.
Direct accretion onto this fast rotating neutron star is impeded by the
propeller mechanism. In this case, around the neutron star magnetosphere a hot
shell is formed that emits thermal X-rays in qualitative and quantitative
agreement with observed properties of the X-ray emission from $\gamma$ Cas. We
suggest that $\gamma$ Cas and its analogs constitute a new subclass of Be-type
X-ray binaries hosting rapidly rotating neutron stars formed in supernova
explosions with small kicks. The subsequent evolutionary stage of $\gamma$ Cas
and its analogs should be the X Per-type binaries comprising low-luminosity
slowly rotating X-ray pulsars. The model explains the enigmatic X-ray emission
from $\gamma$ Cas, and also establishes evolutionary connections between
various types of rotating magnetized neutron stars in Be-binaries.


title:
Droplet breakup driven by shear thinning solutions in a microfluidic
  T-Junction

abstract:
  Droplet-based microfluidics turned out to be an efficient and adjustable
platform for digital analysis, encapsulation of cells, drug formulation, and
polymerase chain reaction. Typically, for most biomedical applications, the
handling of complex, non-Newtonian fluids is involved, e.g. synovial and
salivary fluids, collagen, and gel scaffolds. In this study we investigate the
problem of droplet formation occurring in a microfluidic T-shaped junction,
when the continuous phase is made of shear thinning liquids. At first, we
review in detail the breakup process providing extensive, side-by-side
comparisons between Newtonian and non-Newtonian liquids over unexplored ranges
of flow conditions and viscous responses. The non-Newtonian liquid carrying the
droplets is made of Xanthan solutions, a stiff rod-like polysaccharide
displaying a marked shear thinning rheology. By defining an effective Capillary
number, a simple yet effective methodology is used to account for the
shear-dependent viscous response occurring at the breakup. The droplet size can
be predicted over a wide range of flow conditions simply by knowing the
rheology of the bulk continuous phase. Experimental results are complemented
with numerical simulations of purely shear thinning fluids using Lattice
Boltzmann models. The good agreement between the experimental and numerical
data confirm the validity of the proposed rescaling with the effective
Capillary number.


title: Step scaling in coordinate space: running of the quark mass

abstract:
  We perform a benchmark study of the step scaling procedure for the ratios of
renormalization constants extracted from position space correlation functions.
We work in the quenched approximation and consider the pseudoscalar, scalar,
vector and axial vector bilinears. The pseudoscalar/scalar cases allow us to
obtain the non-perturbative running of the quark mass over a wide range of
energy scales - from around 17 GeV to below 1.5 GeV - which agrees well with
the 4-loop prediction of continuum perturbation theory. We find that step
scaling is feasible in X-space and we discuss its advantages and potential
problems.


title:
Reaching sub-milimag photometric precision on Beta Pictoris with a
  nanosat: the PicSat mission

abstract:
  PicSat is a nanosatellite currently being developed to observe the transit of
the giant planet \b{eta} Pictoris, expected some time between July 2017 and
June 2018. The mission is based on a Cubesat architecture, with a small but
ambitious 2 kg opto-mechanical payload specifically designed for high precision
photometry. The satellite will be launched in early 2017, probably on a 600 km
Sun synchronous orbit. The main objective of the mission is the constant
monitoring of the brightness of Pic at an unprecedented combination of
reliability and precision (200 ppm per hour, with interruptions of at most 30
minutes) to finely characterize the transiting exoplanet and detect exocomets
in the Pictoris system. To achieve this difficult objective, the payload is
designed with a 3.5 cm effective aperture telescope which injects the light in
a single-mode optical fiber linked to an avalanche photodioode. A two-axis
piezoelectric actuation system, driven by a tailor-made feedback loop control
algorithm, is used to lock the fiber on the center of the star in the focal
plane. These actuators complement the attitude determination and control system
of the satellite to maintain the sub-arcsecond pointing accuracy required to
reach the excellent level of photometric precision. Overall, the mission raises
multiple very difficult challenges: high temperature stability of the avalanche
detector (achieved with a thermoelectric colling device), high pointing
accuracy and stability, and short timeframe for the development.


title: A pressurized argon gas TPC as DUNE near detector

abstract:
  DUNE is a new international experiment for neutrino physics and nucleon decay
searches. It will consist of two detectors, about 1300 km apart, exposed to a
multi-megawatt neutrino beam that will be built at Fermilab. One of the two
detectors will be installed several hundred meters downstream of the neutrino
production point with the primary role of characterising the energy spectrum
and composition of the beam as well as performing precision measurements of
neutrino cross sections. For the design of this so-called near detector, the
DUNE Collaboration is considering, among other technologies, a pressurized
argon gas time projection chamber. Such a detector, thanks to its low density
and low detection thresholds, would allow the detailed measurement in argon of
nuclear effects at the neutrino interaction vertex, which are considered at
present one of the most important sources of systematic uncertainty for
neutrino oscillation measurements.


title:
mdBrief - A Fast Online Adaptable, Distorted Binary Descriptor for
  Real-Time Applications Using Calibrated Wide-Angle Or Fisheye Cameras

abstract:
  Fast binary descriptors build the core for many vision based applications
with real-time demands like object detection, Visual Odometry or SLAM. Commonly
it is assumed, that the acquired images and thus the patches extracted around
keypoints originate from a perspective projection ignoring image distortion or
completely different types of projections such as omnidirectional or fisheye.
Usually the deviations from a perfect perspective projection are corrected by
undistortion. Latter, however, introduces severe artifacts if the cameras
field-of-view gets larger. In this paper, we propose a distorted and masked
version of the BRIEF descriptor for calibrated cameras. Instead of correcting
the distortion holistically, we distort the binary tests and thus adapt the
descriptor to different image regions.


title: Linearized supergravity with a dynamical preferred frame

abstract:
  We study supersymmetric extension of the Einstein-aether gravitational model
where local Lorentz invariance is broken down to the subgroup of spatial
rotations by a vacuum expectation value of a timelike vector field called
aether. Embedding aether into a chiral vector superfield, we construct the most
general action which describes dynamics of linear perturbations around the
Lorentz-violating vacuum and is invariant under the linearized supergravity
transformations. The analysis is performed both in the off-shell non-minimal
superfield formulation of supergravity and in the "on-shell" approach invoking
only physical component fields. The resulting model contains a single free
coupling, in addition to the standard supergravity parameters. The spectrum of
physical excitations features an enhanced on-shell gravity multiplet comprising
four states with helicities 2, 3/2, 3/2 and 1 propagating with superluminal
velocity. The remaining excitations propagate with the speed of light. We
outline the observational constraints on the model following from its
low-energy phenomenology.


title: The continuity method on minimal elliptic K\"ahler surfaces

abstract:
  We prove that, on a minimal elliptic K\"ahler surface of Kodaira dimension
one, the continuity method introduced by La Nave and Tian in \cite{LT} starting
from any initial K\"ahler metric converges in Gromov-Hausdorff topology to the
metric completion of the generalized K\"ahler-Einstein metric on its canonical
model constructed by Song and Tian in \cite{ST06}.


title:
Uniqueness and nondegeneracy of positive solutions to a class of
  Kirchhoff equations in $\mathbb{R}^3$

abstract:
  In this paper, we establish a type of uniqueness and nondegeneracy results
for positive solutions to the following nonlocal Kirchhoff equations
\begin{eqnarray*} -\left(a+b\int_{\mathbb{R}^{3}}|\nabla u|^{2}\text{d}
x\right)\Delta u+u=|u|^{p-1}u & & \text{in }\mathbb{R}^{3}, \end{eqnarray*}
where $a,b$ are positive constants and $1<p<5$. Before this paper, it seems
that there have no this type of results even on positive ground states
solutions to Kirchhoff type equations, much less on general positive solutions.
To overcome the difficulty brought by the nonlocality, some new observation on
Kirchhoff equations is found, and some related theories on classical
Schr\"odinger equations are applied.


title: Exchange interactions of CaMnO3 in the bulk and at the surface

abstract:
  In this work, we present electronic and magnetic properties of CaMnO3 (CMO)
as obtained from ab initio calculations. We identify the preferable magnetic
order by means of density functional theory plus Hubbard U calculations and
extract the effective exchange parameters (Jij's) using the magnetic force
theorem. We find that the effects of geometrical relaxation at the surface as
well as the change of crystal field are very strong and are able to influence
the lower energy magnetic configuration. In particular, our analysis reveals
that the exchange interaction between the Mn atoms belonging to the surface and
the subsurface layers is very sensitive to the structural changes. An earlier
study [A. Filippetti and W.E. Pickett, Phys. Rev. Lett. 83, 4184 (1999)]
suggested that this coupling is ferromagnetic and gives rise to the spin flip
process on the surface of CMO. In our work we confirm their finding for an
unrelaxed geometry, but once the structural relaxations are taken into account,
this exchange coupling changes its sign. Thus, we suggest that the surface of
CMO should have the same G-type antiferromagnetic order as in the bulk.
Finally, we show that the suggested SF can be induced in the system by
introducing an excess of electrons.


title: How Document Pre-processing affects Keyphrase Extraction Performance

abstract:
  The SemEval-2010 benchmark dataset has brought renewed attention to the task
of automatic keyphrase extraction. This dataset is made up of scientific
articles that were automatically converted from PDF format to plain text and
thus require careful preprocessing so that irrevelant spans of text do not
negatively affect keyphrase extraction performance. In previous work, a wide
range of document preprocessing techniques were described but their impact on
the overall performance of keyphrase extraction models is still unexplored.
Here, we re-assess the performance of several keyphrase extraction models and
measure their robustness against increasingly sophisticated levels of document
preprocessing.


title:
Equation of State for SU(3) Gauge Theory via the Energy-Momentum Tensor
  under Gradient Flow

abstract:
  The energy density and the pressure of SU(3) gauge theory at finite
temperature are studied by direct lattice measurements of the renormalized
energy-momentum tensor obtained by the gradient flow. Numerical analyses are
carried out with $\beta=6.287$--$7.500$ corresponding to the lattice spacing
$a= 0.013$--$0.061\,\mathrm{fm}$. The spatial (temporal) sizes are chosen to be
$N_s= 64$, $96$, $128$ ($N_{\tau}=12$, $16$, $20$, $22$, $24$) with the aspect
ratio, $5.33 \le N_s/N_{\tau} \le 8$. Double extrapolation, $a\rightarrow 0$
(the continuum limit) followed by $t\rightarrow 0$ (the zero flow-time limit),
is taken using the numerical data. Above the critical temperature, the
thermodynamic quantities are obtained with a few percent precision including
statistical and systematic errors. The results are in good agreement with
previous high-precision data obtained by using the integral method.


title:
The Role of Disc Self-Gravity in Circumbinary Planet Systems: I. Disc
  Structure and Evolution

abstract:
  We present the results of 2-dimensional hydrodynamic simulations of
self-gravitating circumbinary discs around binaries whose parameters match
those of the circumbinary planet-hosting systems Kepler-16, -34 and -35.
Previous work has shown that non-self-gravitating discs in these systems form
an eccentric precessing inner cavity due to tidal truncation by the binary, and
planets which form at large radii migrate until stalling at this cavity. While
this scenario appears to provide a natural explanation for the observed orbital
locations of the circumbinary planets, previous simulations have failed to
match the observed planet orbital parameters. The aim of this work is to
examine the role of self-gravity in modifying circumbinary disc structure as a
function of disc mass, prior to considering the evolution of embedded
circumbinary planets. In agreement with previous work, we find that for disc
masses between 1--5 times the minimum mass solar nebula (MMSN), disc
self-gravity affects modest changes in the structure and evolution of
circumbinary discs. Increasing the disc mass to 10 or 20 MMSN leads to two
dramatic changes in disc structure. First, the scale of the inner cavity
shrinks substantially, bringing its outer edge closer to the binary. Second, in
addition to the eccentric inner cavity, additional precessing eccentric
ring-like features develop in the outer regions of the discs. If planet
formation starts early in the disc lifetime, these changes will have a
significant impact on the formation and evolution of planets and precursor
material.


title: Multi-point Seshadri constants on ruled surfaces

abstract:
  Let $X$ be a surface and let $L$ be an ample line bundle on $X$. We first
obtain a lower bound for the Seshadri constant $\varepsilon(X,L,r)$, when $r
\ge 3$. We then assume that $X$ is a ruled surface and study Seshadri constants
on $X$ in greater detail. We also make precise computations of Seshadri
constants on $X$ in some cases.


title: Stress engineering with silicon nitride stressors for Ge-on-Si lasers

abstract:
  Side and top silicon nitride stressors were proposed and shown to be
effective ways to reduce the threshold current Ith and improve the wall-plug
efficiency {\eta}wp of Ge-on-Si lasers. Side stressors only turned out to be a
more efficient way to increase {\eta}wp than using top and side stressors
together. With the side stressors only and geometry optimizations, a {\eta}wp
of 30.5% and an Ith of 50 mA (Jth of 37 kA/cm2) can be achieved with the defect
limited carrier lifetime of 1 nsec. With the defect limited carrier lifetime of
10 nsec, an Ith of 7.8 mA (Jth of 5.8 kA/cm2) and a wall-plug efficiency of
38.7% can be achieved. These are tremendous improvements from the case without
any stressors. These results give strong support to the Ge-on-Si laser
technology and provide an effective way to improve the Ge laser performance.


title:
Equilibria of a clamped Euler beam (Elastica) with distributed load:
  large deformations

abstract:
  We present some novel equilibrium shapes of a clamped Euler beam (Elastica
from now on) under uniformly distributed dead load orthogonal to the straight
reference configuration. We characterize the properties of the minimizers of
total energy, determine the corresponding Euler-Lagrange conditions and prove,
by means of direct methods of calculus of variations, the existence of curled
local minimizers. Moreover, we prove some sufficient conditions for stability
and instability of particular solutions of the Euler-Lagrange conditions that
can be applied to numerically found curled shapes.


title:
Three-dimensional organic Dirac-line materials due to nonsymmorphic
  symmetry: a data mining approach

abstract:
  A data mining study of electronic Kohn-Sham band structures was performed to
identify Dirac materials within the Organic Materials Database (OMDB). Out of
that, the 3-dimensional organic crystal
5,6-bis(trifluoromethyl)-2-methoxy-1$H$-1,3-diazepine was found to host
different Dirac line-nodes within the band structure. From a group theoretical
analysis, it is possible to distinguish between Dirac line-nodes occurring due
to 2-fold degenerate energy levels protected by the monoclinic crystalline
symmetry and 2-fold degenerate accidental crossings protected by the topology
of the electronic band structure. The obtained results can be generalized to
all materials having the space group $P2_1/c$ (No. 14, $C^5_{2h}$) by
introducing three distinct topological classes.


title: Hanf numbers via accessible images

abstract:
  We present several new model-theoretic applications of the fact that, under
the assumption that there exists a proper class of almost strongly compact
cardinals, the powerful image of any accessible functor is accessible. In
particular, we generalize to the context of accessible categories the recent
Hanf number computations of Baldwin and Boney, namely that in an abstract
elementary class (AEC) if the joint embedding and amalgamation properties hold
for models of size up to a sufficiently large cardinal, then they hold for
models of arbitrary size. Moreover, we prove that, under the above-mentioned
large cardinal assumption, every metric AEC is strongly d-tame, strengthening a
result of Boney and Zambrano and pointing the way to further generalizations.


title: Davenport-Hasse's Theorem for Polynomial Gauss Sums over Finite Fields

abstract:
  In this paper, we study the polynomial Gauss sums over finite fields, and
present an analogue of Davenport-Hasse's theorem for the entire polynomial
Gauss sums, which is a generalization of the previous result obtained by Hayes.


title: A centrally heated dark halo for our Galaxy

abstract:
  We construct a new family of models of our Galaxy in which dark matter and
disc stars are both represented by distribution functions that are analytic
functions of the action integrals of motion. The potential that is
self-consistently generated by the dark matter, stars and gas is determined,
and parameters in the distribution functions are adjusted until the model is
compatible with observational constraints on the circular-speed curve, the
vertical density profile of the stellar disc near the Sun, the kinematics of
nearly 200 000 giant stars within 2 kpc of the Sun, and estimates of the
optical depth to microlensing of bulge stars. We find that the data require a
dark halo in which the phase-space density is approximately constant for
actions |J| \lesssim 140 kpc km ^-1. In real space these haloes have core radii
~ 2 kpc.


title:
Lepton acceleration in the vicinity of the event horizon: High-energy
  and Very-high-energy emissions from rotating black holes with various masses

abstract:
  We investigate the electrostatic acceleration of electrons and positrons in
the vicinity of the event horizon, applying the pulsar outer-gap model to black
hole magnetospheres. During a low accretion phase, the radiatively inefficient
accretion flow (RIAF) cannot emit enough MeV photons that are needed to sustain
the force-free magnetosphere via two-photon collisions. In such a
charge-starved region (or a gap), an electric field arises along the magnetic
field lines to accelerate electrons and positrons into ultra-relativistic
energies. These relativistic leptons emit copious gamma-rays via curvature and
inverse-Compton (IC) processes. Some of such gamma-rays collide with the
submillimeter-IR photons emitted from the RIAF to materialize as pairs, which
polarize to partially screen the original acceleration electric field. It is
found that the gap gamma-ray luminosity increases with decreasing accretion
rate. However, if the accretion rate decreases too much, the diminished RIAF
soft photon field can no longer sustain a stationary pair production within the
gap. As long as a stationary gap is formed, the magnetosphere becomes
force-free outside the gap by the cascaded pairs, irrespective of the BH mass.
If a nearby stellar-mass black hole (BH) is in quiescence, or if a galactic
intermediate-mass BH is in a very low accretion state, its curvature and IC
emissions are found to be detectable with Fermi/LAT and imaging atmospheric
Cherenkov telescopes (IACT). If a low-luminosity active galactic nucleus is
located within a few tens of Mpc, the IC emission from its super-massive BH is
marginally detectable with IACT.


title:
Biseparability of 3-qubits density matrices using Hilbert-Schmidt
  decompositions: Sufficient conditions and explicit expressions

abstract:
  Hilbert-Schmidt (HS) decompositions and Frobenius norms are used to analyze
biseparability of 3-qubit systems, with particular emphasis on density matrices
with maximally disordered subsystems (MDS) and on the W state mixed with white
noise. The biseparable form of a MDS density matrix is obtained by using the
Bell states of a 2-qubit subsystem, multiplied by density matrices of the third
qubit, which include the relevant HS parameters. Using our methods a sufficient
condition and explicit biseparability of the W state mixed with white noise are
given. They are compared with the sufficient condition for explicit full
separability given in a previous work.


title: Quadratically damped oscillators with non-linear restoring force

abstract:
  In this paper we qualitatively analyse quadratically damped oscillators with
non-linear restoring force. In particular, we obtain Hamiltonian structure and
analytical form of the energy functions.


title: The Conformal Hyperplet

abstract:
  We introduce a finite off-shell hypermultiplet with no off-shell central
charge. This requires 192+192 degrees of freedom, all but 8+8 of which are
auxiliary or gauge. In the absence of supergravity, the model has a
saddle-point vacuum instability implying ghost-like propagators. These are
cured by realizing the model superconformally, such that the erstwhile ghosts
are realized as compensators. Gauge fixing these links the physical
hypermultiplets to supergravity. This evokes the prospect of realizing ${\cal
N}=4$ Super Yang-Mills theory off-shell.


title:
On the distribution of the Picard ranks of the reductions of a $K3$
  surface

abstract:
  We report on our results concerning the distribution of the geometric Picard
ranks of $K3$ surfaces under reduction modulo various primes. In the situation
that $\rk \Pic S_{\overline{K}}$ is even, we introduce a quadratic character,
called the jump character, such that $\rk \Pic S_{\overline\bbF_{\!\frakp}} >
\rk \Pic S_{\overline{K}}$ for all good primes, at which the character
evaluates to $(-1)$.


title: Efficient technique for computational design of thermoelectric materials

abstract:
  Efficient thermoelectric materials are highly desirable, and the quest for
finding them has intensified as they could be promising alternatives to fossil
energy sources. Here we present a general first-principles approach to predict,
in multicomponent systems, efficient thermoelectric compounds. The method
combines a robust evolutionary algorithm, a Pareto multiobjective optimization,
density functional theory and a Boltzmann semi-classical calculation of
thermoelectric efficiency. To test the performance and reliability of our
overall framework, we use the well-known system Bi$_2$Te$_3$-Sb$_2$Te$_3$.


title: Considerations on Xi- reconstruction in LHCb

abstract:
  This paper describes an alternative method of charged hyperon reconstruction
applicable to the LHCb experiment. It extends the seminal work of the FOCUS
collaboration to the specific detector layout of LHCb and addresses the
reconstruction ambiguities reported in their earlier work, leading to
improvements in the reconstruction efficiency for the specific cases of Xi- and
Omega- baryon decays to a charged meson and a Lambda baryon.


title: Reduced density matrix and order parameters of a topological insulator

abstract:
  It has been recently proposed that the reduced density matrix may be used to
derive the order parameter of a condensed matter system. Here we propose order
parameters for the phases of a topological insulator, specifically a spinless
Su-Schrieffer-Heeger (SSH) model, and consider the effect of short-range
interactions. All the derived order parameters and their possible corresponding
quantum phases are verified by the entanglement entropy and electronic
configuration analysis results. The order parameter appropriate to the
topological regions is further proved by calculating the Berry phase under
twisted boundary conditions. It is found that the topological non-trivial phase
is robust to the introduction of repulsive inter-site interactions, and can
appear in the topological trivial parameter region when appropriate
interactions are added.


title: A Short Note on Polynomial Automorphisms

abstract:
  In this paper, we construct explicitely polynomial automorphisms of affine
n-space for certain n. More precisely, we construct algebraic subgroups of the
general polynomial group GA_n(k) where k is an arbitrary base ring of
characteristic zero.


title: On a hyperbolic system arising in liquid crystals modeling

abstract:
  We consider a model of liquid crystals, based on a nonlinear hyperbolic
system of differential equations, that represents an inviscid version of the
model proposed by Qian and Sheng. A new concept of dissipative solution is
proposed, for which a global-in-time existence theorem is shown. The
dissipative solutions enjoy the following properties:
  (i) they exist globally in time for any finite energy initial data;
  (ii) dissipative solutions enjoying certain smoothness are classical
solutions;
  (iii) a dissipative solution coincides with a strong solution originating
from the same initial data as long as the latter exists.


title: Regularity of Harmonic Maps from Polyhedra to CAT(1) Spaces

abstract:
  We determine regularity results for energy minimizing maps from an
$n$-dimensional Riemannian polyhedral complex $X$ into a CAT(1) space. Provided
that the metric on $X$ is Lipschitz regular, we prove H\"older regularity with
H\"older constant and exponent dependent on the total energy of the map and the
metric on the domain. Moreover, at points away from the $(n-2)$-skeleton, we
improve the regularity to locally Lipschitz. Finally, for points $x \in
X^{(k)}$ with $k \leq n-2$, we demonstrate that the H\"older exponent depends
on geometric and combinatorial data of the link of $x \in X$.


title: On the convergence rate of the three operator splitting scheme

abstract:
  The three operator splitting scheme was recently proposed by [Davis and Yin,
2015] as a method to optimize composite objective functions with one convex
smooth term and two convex (possibly non-smooth) terms for which we have access
to their proximity operator. In this short note we provide an alternative proof
for the sublinear rate of convergence of this method.


title:
Another look at the size of the low-surface brightness galaxy VCC 1661
  in the Virgo Cluster

abstract:
  We present new wide-field images of the low-surface brightness Virgo Cluster
dwarf galaxy VCC 1661. The extant literature lists a broad range of radii for
this object, covering a factor of more than four, depending on the filters used
and the details of the analyses. While some studies find a radius typical of
other Virgo dwarfs and note the normality of this object, any larger spatial
extent, taken at face value, would render this galaxy the largest dwarf in the
Virgo Cluster samples. Confirmation of a large extent of dwarf galaxies has
often led to the discovery of tidal tails and would then, also in VCC 1661,
indicate a severe state of tidal disruption. Given the importance of galactic
sizes for assessing tidal interactions of the satellites with their hosts, we
thus combine our surface brightness profile with data from the literature to
investigate further the nature of this galaxy. However, our new characteristic
radius for VCC 1661 of $r_e=24.1$"$\pm7.7$" and the previously noted smooth
appearance of its isophotes are fully consistent with the remainder of the
ACSVCS dwarf galaxy population without any need to invoke tidal perturbations.


title:
Valuation Theory, Riemann Varieties and the Structure of integral
  Preschemes

abstract:
  In this work we show that the classical subject of general valuation theory
and Zariski-Riemann varieties has a much wider scope than commutative algebra
and desingularization theory. We construct and investigate birational
projective limit objects appropriate for the study of countably many birational
models at one time. We use nonseparated Riemann varieties to investigate the
birational structure of integral preschemes satisfying the existence condition
of the valuative criterion of properness.


title:
ZrO$_2$ tapes as an alternative low-cost flexible substrate to
  artificially nanostructured materials

abstract:
  We associate tape casting and magnetron sputtering techniques to engineer
flexible nanostructures using ZrO$_2$ green tape as substrate. We
systematically investigate the structural, magnetic and electrical properties
of NiFe/Cr/NiFe trilayer nanostructures, with variable thickness values of the
NiFe and Cr layers, grown onto rigid glass and flexible ZrO$_2$ tape
substrates. We verify the mirroring of these properties in the trilayer
nanostructures, irrespective on the kind of employed substrate. The fact that
the trilayer nanostructures can be reproduced in distinct substrates
corresponds to an important advance for their applicability. The results place
the ZnO$_2$ green tape as an attractive candidate for application as low-cost
flexible substrate in the development of electrical and magnetic sensor
elements with high sensitivity to mechanic stress.


title: Meet-reducible submaximal clones determined by two central relations

abstract:
  Let rho and sigma be two central relations on a finite set A. It is known
that the clones Pol(rho) and Pol(sigma) which consists of all operations on A
that preserve rho respectively sigma are among the maximal clones on A. In this
paper, we find all central relations sigma such that the join clone of Pol(rho)
and Pol(sigma) is a maximal subclone of Pol(rho) where rho is a fixed central
relation.


title: Axion crystals

abstract:
  The low-energy effective theories for gapped insulators are classified by
three parameters: permittivity $\epsilon$, permeability $\mu$, and theta angle
$\theta$. Crystals with periodic $\epsilon$ are known as photonic crystals. We
here study the band structure of photons in a new type of crystals with
periodic $\theta$ (modulo $2\pi$) in space, which we call the axion crystals.
We find that the axion crystals have a number of new properties that the usual
photonic crystals do not possess, such as the helicity-dependent mass gap and
nonrelativistic gapless dispersion relation at small momentum. We briefly
discuss possible realizations of axion crystals in condensed matter systems and
high-energy physics.


title: Classification of crescent configurations

abstract:
  Let $n$ points be in crescent configurations in $\mathbb{R}^d$ if they lie in
general position in $\mathbb{R}^d$ and determine $n-1$ distinct distances, such
that for every $1 \leq i \leq n-1$ there is a distance that occurs exactly $i$
times. Since Erd\H{o}s' conjecture in 1989 on the existence of $N$ sufficiently
large such that no crescent configurations exist on $N$ or more points, he,
Pomerance, and Pal\'asti have given constructions for $n$ up to $8$ but nothing
is yet known for $n \geq 9$. Most recently, Burt et. al. had proven that a
crescent configuration on $n$ points exists in $\mathbb{R}^{n-2}$ for $n \geq
3$. In this paper, we study the classification of these configurations on $4$
and $5$ points through graph isomorphism and rigidity. Our techniques, which
can be generalized to higher dimensions, offer a new viewpoint on the problem
through the lens of distance geometry and provide a systematic way to construct
crescent configurations.


title:
Walks on Graphs and Their Connections with Tensor Invariants and
  Centralizer Algebras

abstract:
  The number of walks of $k$ steps from the node $\mathsf{0}$ to the node
$\lambda$ on the representation graph (McKay quiver) determined by a finite
group $\mathsf{G}$ and a $\mathsf{G}$-module $\mathsf{V}$ is the multiplicity
of the irreducible $\mathsf{G}$-module $\mathsf{G}_\lambda$ in the tensor power
$\mathsf{V}^{\otimes k}$, and it is also the dimension of the irreducible
module labeled by $\lambda$ for the centralizer algebra
$\mathsf{Z}_k(\mathsf{G}) = {\mathsf{End}}_\mathsf{G}(\mathsf{V}^{\otimes k})$.
This paper explores ways to effectively calculate that number using the
character theory of $\mathsf{G}$. We determine the corresponding Poincar\'e
series. The special case $\lambda = \mathsf{0}$ gives the Poincar\'e series for
the tensor invariants $\mathsf{T}(\mathsf{V})^\mathsf{G} = \bigoplus_{k
=0}^\infty (\mathsf{V}^{\otimes k})^\mathsf{G}$. When $\mathsf{G}$ is abelian,
we show that the exponential generating function for the number of walks is a
product of generalized hyperbolic functions. Many graphs (such as circulant
graphs) can be viewed as representation graphs, and the methods presented here
provide efficient ways to compute the number of walks on them.


title:
Sharp Estimates for Geman-Yor Processes and applications to Arithmetic
  Average Asian options

abstract:
  We prove the existence and pointwise lower and upper bounds for the
fundamental solution of the degenerate second order partial differential
equation related to Geman-Yor stochastic processes, that arise in models for
option pricing theory in finance.
  Lower bounds are obtained by using repeatedly an invariant Harnack inequality
and by solving an associated optimal control problem with quadratic cost. Upper
bounds are obtained by the fact that the optimal cost satisfies a specific
Hamilton-Jacobi-Bellman equation.


title: Role of evaporation in gravitational collapse

abstract:
  We investigate the possibility that quantum effects responsible for black
hole radiation do not allow for hori- zon crossing of gravitationally
collapsing matter in a finite time as seen by distant observers. We consider
this in the context of the collapse of evaporating massive thin dust shells
using two families of metrics to describe the exterior geometry: the outgoing
Vaidya metric and the retarded Schwarzschild metric. We describe how this
hypothesis results in a modified equation of motion for the shell. In each case
the collapse is accelerated due to evaporation, but the Schwarzschild radius is
not crossed. Instead the shell is always at a certain sub-Planckian distance
from this would-be horizon that depends only on the mass and evaporation rate,
while a comoving observer encounters firewall-like energy density and flux with
a natural cutoff.


title:
On the Connection of Gamma-Ray Bursts and X-Ray Flashes in the BATSE and
  RHESSI Databases

abstract:
  Classification of gamma-ray bursts (GRBs) into groups has been intensively
studied by various statistical tests in previous years. It has been suggested
that there was a distinct group of GRBs, beyond the long and short ones, with
intermediate durations. However, such a group is not securely confirmed yet.
Strangely, concerning the spectral hardness, the observations from the Swift
and RHESSI satellites give different results. For the Swift/BAT database it is
found that the intermediate-duration bursts might well be related to so-called
X-ray flashes (XRFs). On the other hand, for the RHESSI dataset the
intermediate-duration bursts seem to be spectrally too hard to be given by
XRFs. The connection of the intermediate-duration bursts and XRFs for the BATSE
database is not clear as well. The purpose of this article is to check the
relation between XRFs and GRBs for the BATSE and RHESSI databases,
respectively. We use an empirical definition of XRFs introduced by other
authors earlier. For the RHESSI database we also use a transformation between
the detected counts and the fluences based on the simulated detector response
function. The purpose is to compare the hardnesses of GRBs with the definition
of XRFs. There is a 1.3-4.2 % fraction of XRFs in the whole BATSE database. The
vast majority of the BATSE short bursts are not XRFs because only 0.7-5.7 % of
the short bursts can be given by XRFs. However, there is a large uncertainty in
the fraction of XRFs among the intermediate-duration bursts. The fraction of
1-85 % of the BATSE intermediate-duration bursts can be related to XRFs. For
the long bursts this fraction is between 1.0 % and 3.4 %. The uncertainties in
these fractions are large, however it can be claimed that all BATSE
intermediate-duration bursts cannot be given by XRFs. At least 79 % of RHESSI
short bursts, at least 53 % of RHESSI intermediate-duration bursts, and at
least...


title:
Characteristic polynomials of Linial arrangements for exceptional root
  systems

abstract:
  The (extended) Linial arrangement $\mathcal{L}_{\Phi}^m$ is a certain finite
truncation of the affine Weyl arrangement of a root system $\Phi$ with a
parameter $m$. Postnikov and Stanley conjectured that all roots of the
characteristic polynomial of $\mathcal{L}_{\Phi}^m$ have the same real part,
and this has been proved for the root systems of classical types. In this paper
we prove that the conjecture is true for exceptional root systems when the
parameter $m$ is sufficiently large. The proof is based on representations of
the characteristic quasi-polynomials in terms of Eulerian polynomials.


title:
Recovering a compact Hausdorff space $X$ from the compatibility ordering
  on $C(X)$

abstract:
  Let $f$ and $g$ be scalar-valued, continuous functions on some topological
space. We say that $g$ dominates $f$ in the compatibility ordering if $g$
coincides with $f$ on the support of $f$. We prove that two compact Hausdorff
spaces are homeomorphic if and only if there exists a compatibility isomorphism
between their families of scalar-valued, continuous functions. We derive the
classical theorems of Gelfand-Kolmogorov, Milgram and Kaplansky as easy
corollaries to our result as well as a theorem of Jarosz [Bull. Canad. Math.
Soc. 1990] thereby building~a common roof for these theorems. Sharp
automatic-continuity results for compatibility isomorphisms are also
established.
  Added on 30.03.2021: Unfortunately, Theorem 1.1 of the present manuscript is
flawed. Erratum and addendum written jointly with D. H. Leung is attached.
Besides providing an amendment to the said statement, it also contains more
complete proof of Proposition 4.1. Theorems 1.2--1.3 are unaffected.