total 1389took 0.10s

Effects of high vs moderate-intensity training on neuroplasticity and functional recovery after focal ischemiaFeb 08 2018Background and Purpose: This study was designed to compare the effects of high-intensity interval training (HIT) and moderate-intensity continuous training (MOD) on functional recovery and cerebral plasticity during the first 2 weeks following cerebral ... More

Retrieving information from a noisy "knowledge network"Apr 30 2007Jul 05 2007We address the problem of retrieving information from a noisy version of the ``knowledge networks'' introduced by Maslov and Zhang. We map this problem onto a disordered statistical mechanics model, which opens the door to many analytical and numerical ... More

Domain configurations in Co/Pd and L10-FePt nanowire arrays with perpendicular magnetic anisotropyJan 12 2016Perpendicular magnetic anisotropy [Co/Pd]15 and L10-FePt nanowire arrays of period 63 nm with linewidths 38 nm and 27 nm and film thickness 27 nm and 20 nm respectively were fabricated using a self-assembled PS-b-PDMS diblock copolymer film as a lithographic ... More

Lifting to cluster-tilting objects in higher cluster categoriesOct 19 2008Dec 29 2008In this note, we consider the $d$-cluster-tilted algebras, the endomorphism algebras of $d$-cluster-tilting objects in $d$-cluster categories. We show that a tilting module over such an algebra lifts to a $d$-cluster-tilting object in this $d$-cluster ... More

On Hawking's Local Rigidity Theorems for Charged Black HolesMar 27 2009We show the existence of a Hawking vector field in a full neighborhood of a local, regular, bifurcate, non-expanding horizon embedded in a smooth Einstein-Maxwell space-time without assuming the underlying space-time is analytic. It extends one result ... More

Energy Estimates and Gravitational CollapseMay 13 2011We study the cancelations in the energy estimates for Einstein vacuum equations in order to prove the formation of black holes along evolutions. The novelty of the paper is that, we completely avoid using rotation vector fields to establish the global ... More

Dynamical formation of black holes due to the condensation of matter fieldMay 30 2011The purpose of the paper is to understand a mechanism of evolutionary formation of trapped surfaces when there is an electromagnetic field coupled to the background space-time. Based on the short pulse ansatz, on a given finite outgoing null hypersurface ... More

Results from H.E.S.S. Observations of Relativistic SourcesJun 24 2010The High Energy Stereoscopic System (H.E.S.S.) is a southern hemisphere array of four Imaging Atmospheric Cherenkov Telescopes observing the sky in the very high energy gamma-ray range (E $>$ 100 GeV). VHE observations are an invaluable tool to study ... More

Lyapunov exponents as a dynamical indicator of a phase transitionFeb 19 2001We study analytically the behavior of the largest Lyapunov exponent $\lambda_1$ for a one-dimensional chain of coupled nonlinear oscillators, by combining the transfer integral method and a Riemannian geometry approach. We apply the results to a simple ... More

Breathers and solitons of generalized nonlinear Schrödinger equations as degenerations of algebro-geometric solutionsJun 01 2011We present new solutions in terms of elementary functions of the multi-component nonlinear Schr\"odinger equations and known solutions of the Davey-Stewartson equations such as multi-soliton, breather, dromion and lump solutions. These solutions are given ... More

Un critère de récurrence pour certains espaces homogènesJul 19 2016Let $G$ be a real connected algebraic semi-simple Lie group, and $H$ an algebraic subgroup of $G$. Let $\mu$ be a probability measure on $G$, with finite exponential moment, whose support spans a Zariski-dense subsemigroup of $G$. Let $X=G/H$ be the quotient ... More

Dilatonic String through black holesNov 19 1999We study the gravi-dilaton field of a Schwarzschild black hole pierced by a thin cosmic string in both massless and massive dilatonic gravity. We conclude that in the thin vortex approximation the string's spacetime is asymptotically flat with a conical ... More

Static black holes in scalar tensor gravitySep 15 2000We study static black hole solutions in scalar tensor gravity. We present exact solutions in hiperextended models with a quadratic scalar potential.

About the dynamics and thermodynamics of trapped ionsFeb 16 2009May 14 2009This tutorial introduces the dynamics of charged particles in a radiofrequency trap in a very general manner to point out the differences between the dynamics in a quadrupole and in a multipole trap. When dense samples are trapped, the dynamics is modified ... More

Quantum Measurements Cannot be Proved to be RandomAug 30 2010We show that it is impossible to prove that the outcome of a quantum measurement is random.

Twisted gamma filtration and algebras with orthogonal involutionNov 14 2012For the Grothendieck group of a split simple linear algebraic group, the twisted gamma-filtration provides a useful tool for constructing torsion elements in gamma-rings of twisted flag varieties. In this paper, we construct a non-trivial torsion element ... More

Un contre-exemple à la dichotomie récurrence/transience sur les espaces homogènesJul 19 2016Take $G$ a locally compact second-countable group, and $H$ a subgroup of $G$. Choose $\mu$ a probability measure on $G$, such that the group spanned by its support is dense in $G$, and consider the Markov chain on the homogeneous space $X=G/H$ with transition ... More

The J-invariant and Tits algebras for groups of inner type E6Dec 07 2011Jan 30 2012A connection between the indices of the Tits algebras of a split linear algebraic group G and the degree one parameters of its motivic J-invariant was introduced by Queguiner-Mathieu, Semenov and Zainoulline through use of the second Chern class map in ... More

Geometry of maximum likelihood estimation in Gaussian graphical modelsDec 13 2010May 29 2012We study maximum likelihood estimation in Gaussian graphical models from a geometric point of view. An algebraic elimination criterion allows us to find exact lower bounds on the number of observations needed to ensure that the maximum likelihood estimator ... More

Primitive stability and Bowditch's BQ-condition are equivalentJan 05 2019We prove the equivalence of two conditions on the primitive elements in an $SL(2,\mathbb C)$ representation of the free group $F_2$ on two generators, which may hold even when the image of $F_2$ is not discrete. One is Minsky's condition of primitive ... More

On algebraic damping close to inhomogeneous Vlasov equilibria in multi-dimensional spacesOct 30 2012We investigate the asymptotic damping of a perturbation around inhomogeneous stable stationary states of the Vlasov equation in spatially multi-dimensional systems. We show that branch singularities of the Fourier-Laplace transform of the perturbation ... More

Cosmic strings in axionic-dilatonic gravitySep 29 2000Oct 03 2000We first consider local cosmic strings in dilaton-axion gravity and show that they are singular solutions. Then we take a supermassive Higgs limit and present expressions for the fields at far distances from the core by applying a Pecci-Quinn and a duality ... More

On the neighborhood of an inhomogeneous stable stationary solution of the Vlasov equation - Case of the Hamiltonian mean-field modelNov 13 2013We consider the one-dimensional Vlasov equation with an attractive cosine potential, and its non homogeneous stationary states that are decreasing functions of the energy. We show that in the Sobolev space $W^{1,p}$ ($p>2$) neighborhood of such a state, ... More

On high order accurate schemes for space fractional diffusion equations with variable coefficientsAug 29 2016Sep 29 2016We study high order schemes for spatial fractional differential equations with variable coefficients. Approximations of fractional derivatives basing on the weighted and shifted Gr\"unwald-Letnikov formulas and weighted and shifted Lubich formulas are ... More

Construction of Cauchy Data of Vacuum Einstein field equations Evolving to Black HolesJul 13 2012We show the existence of complete, asymptotically flat Cauchy initial data for the vacuum Einstein field equations, free of trapped surfaces, whose future development must admit a trapped surface. Moreover, the datum is exactly a constant time slice in ... More

Heights and the Specialization Map for Families of Elliptic Curves over P^nSep 10 2014Jun 22 2015For $n\geq 2$, let $K=\overline{\mathbb{Q}}(\mathbb{P}^n)=\overline{\mathbb{Q}}(T_1, \ldots, T_n)$. Let $E/K$ be the elliptic curve defined by a minimal Weiestrass equation $y^2=x^3+Ax+B$, with $A,B \in \overline{\mathbb{Q}}[T_1, \ldots, T_n]$. There's ... More

Stochastic network formation and homophilyMay 24 2015This is a chapter of the forthcoming Oxford Handbook on the Economics of Networks.

Robustness of complex many-body networks: Novel perspective in 2D metal-insulator transitionFeb 10 2014May 27 2014We present a novel theoretical framework established by complex network analysis for understanding the phase transition beyond the Landau symmetry breaking paradigm. In this paper we take a two-dimensional metal-insulator transition driven by electron ... More

Transport phenomena and Weyl correction in effective holographic theory of momentum dissipationFeb 08 2019We construct a higher derivative theory involving an axionic field and the Weyl tensor in four dimensional spacetime. Up to the first order of the coupling parameters, the charged black brane solution with momentum dissipation in a perturbative manner ... More

On high order accurate schemes for space fractional diffusion equations with variable coefficientsAug 29 2016Oct 14 2016We study high order schemes for spatial fractional differential equations with variable coefficients. Approximations of fractional derivatives basing on the weighted and shifted Gr\"unwald-Letnikov formulas and weighted and shifted Lubich formulas are ... More

Vorticity Budget of Weak Thermal Convection in Keplerian disksJan 20 2000Apr 20 2000By employing the equations of mean-square vorticity (enstrophy) fluctuations in strong shear flows, we demonstrate that unlike energy production of turbulent vorticity in nonrotating shear flows, the turbulent vorticity of weak convection in Keplerian ... More

Thermodynamics of Radiation Pressure and Photon MomentumAug 31 2017Theoretical analyses of radiation pressure and photon momentum in the past 150 years have focused almost exclusively on classical and/or quantum theories of electrodynamics. In these analyses, Maxwell's equations, the properties of polarizable and/or ... More

Ensemble Inequivalence in Mean-field Models of MagnetismSep 16 2002Mean-field models, while they can be cast into an {\it extensive} thermodynamic formalism, are inherently {\it non additive}. This is the basic feature which leads to {\it ensemble inequivalence} in these models. In this paper we study the global phase ... More

Inequivalence of ensembles in a system with long range interactionsFeb 02 2001We study the global phase diagram of the infinite range Blume-Emery-Griffiths model both in the canonical and in the microcanonical ensembles. The canonical phase diagram is known to exhibit first order and continuous transition lines separated by a tricritical ... More

Spy the little Spies - Security and Privacy issues of Smart GPS trackersFeb 14 2019Tracking expensive goods and/or targeted individuals with high-tech devices has been of high interest for the last 30 years. More recently, other use cases such as parents tracking their children have become popular. One primary functionality of these ... More

To Motivate Social Grouping in Wireless NetworksNov 05 2015Jun 21 2016We consider a group of neighboring smartphone users who are roughly at the same time interested in the same network content, called common interests. However, ever-increasing data traffic challenges the limited capacity of base-stations (BSs) in wireless ... More

On Gromov-Witten theory of projective bundlesJul 04 2016Oct 07 2018Given two equivariant vector bundles over an algebraic GKM manifold with the same equivariant Chern classes, we show that the genus zero equivariant Gromov--Witten theory of their projective bundles are naturally isomorphic.

Delta-33 medium mass modification and pion spectraJul 13 2005May 21 2007We study the pi+- spectra obtained in 2,4,6,8 A GeV Au-Au collisions within the thermal model. We find that the main features of the data can be well described after we include the pions from the decay of the Delta-resonance with medium mass modification. ... More

Deep Global-Connected Net With The Generalized Multi-Piecewise ReLU Activation in Deep LearningJun 19 2018Recent Progress has shown that exploitation of hidden layer neurons in convolution neural networks incorporating with a carefully designed activation function can yield better classification results in the field of computer vision. The paper firstly introduces ... More

Particle motion and chaosJul 02 2018In this note, we explicitly illuminate that the velocity bound in the gravity corresponds to the chaos bound in the quantum system by studying the particle free falling in hyperscaling violating (HV) black brane. We also study the particle falling in ... More

The Onsager AlgebraMay 27 2012In this thesis, four realizations of the Onsager algebra are explored. We begin with its original definition as introduced by Lars Onsager. We then examine how the Onsager algebra can be presented as a Lie algebra with two generators and two relations. ... More

Quasi-Periodic Oscillations in magnetars: linking variability and emissionOct 24 2012I present recent results studying flare emission in magnetars. Strong quasi-periodic oscillations observed in the tail of giant magnetar flares are frequently interpreted as evidence for global seismic oscillations. I demonstrate that such a global oscillation ... More

Keyphrase Extraction : Enhancing ListsApr 01 2012This paper proposes some modest improvements to Extractor, a state-of-the-art keyphrase extraction system, by using a terabyte-sized corpus to estimate the informativeness and semantic similarity of keyphrases. We present two techniques to improve the ... More

Abundances and ages of the deconvolved thin/thick disks of the GalaxyNov 02 2004We have investigated the abundance of several chemical elements in two large stellar samples kinematically representative of the thin and the thick disks of the Galaxy. Chemical, kinematical and age data have been collected from high quality sources in ... More

Concept Clustering and Knowledge Integration from a Children's DictionaryMar 05 1997Knowledge structures called Concept Clustering Knowledge Graphs (CCKGs) are introduced along with a process for their construction from a machine readable dictionary. CCKGs contain multiple concepts interrelated through multiple semantic relations together ... More

The Chaotic Ball: An Intuitive Analogy for EPR ExperimentsNov 21 1996Aug 08 2004Actual realisations of EPR experiments do {\em not} demonstrate non-locality. A model is presented that should enable non-specialists as well as specialists to understand how easy it is to find realistic explanations for the observations. The model also ... More

Homodyne detection and parametric down-conversion: a classical approach applied to proposed "loophole-free" Bell testsAug 02 2005A classical model is presented for the features of parametric down-conversion and homodyne detection relevant to recent proposed ``loophole-free'' Bell tests. The Bell tests themselves are uncontroversial: there are no obvious loopholes that might cause ... More

Cosmic strings in dilaton gravityJan 09 1997Jun 06 1997We examine the metric of an isolated self-gravitating abelian-Higgs vortex in dilatonic gravity for arbitrary coupling of the vortex fields to the dilaton. We look for solutions in both massless and massive dilaton gravity. We compare our results to existing ... More

A tree metric using structure and length to capture distinct phylogenetic signalsJul 18 2015Sep 11 2015Phylogenetic trees are a central tool in understanding evolution. They are typically inferred from sequence data, and capture evolutionary relationships through time. It is essential to be able to compare trees from different data sources (e.g. several ... More

An l1-Oracle Inequality for the LassoJul 27 2010The Lasso has attracted the attention of many authors these last years. While many efforts have been made to prove that the Lasso behaves like a variable selection procedure at the price of strong (though unavoidable) assumptions on the geometric structure ... More

Lossless Quantum CompressionAug 23 2005Mar 21 2006We describe lossless quantum compression of unknown mixtures (of non-orthogonal states) and give an expression of the optimal rate of compression.

Preferential Attachment in Systems and Networks of Constant SizeNov 12 2018We propose a preferential-attachment-type model for a system of constant size which applies to urn/ball systems and to networks. It yields a power law for the size (or degree) distribution with exponential cutoff depending on parameters. This distribution ... More

Learning directed acyclic graphs based on sparsest permutationsJul 01 2013Feb 24 2014We consider the problem of learning a Bayesian network or directed acyclic graph (DAG) model from observational data. A number of constraint-based, score-based and hybrid algorithms have been developed for this purpose. For constraint-based methods, statistical ... More

Limit points of lines of minima in Thurston's boundary of Teichmueller spaceMar 09 2003Given two measured laminations mu and nu in a hyperbolic surface which fill up the surface, Kerckhoff [Lines of Minima in Teichmueller space, Duke Math J. 65 (1992) 187-213] defines an associated line of minima along which convex combinations of the length ... More

Extremal theory of locally sparse multigraphsAug 31 2016An $(n,s,q)$-graph is an $n$-vertex multigraph where every set of $s$ vertices spans at most $q$ edges. In this paper, we determine the maximum product of the edge multiplicities in $(n,s,q)$-graphs if the congruence class of $q$ modulo ${s\choose 2}$ ... More

Macro-level Indicators of the Relations between Research Funding and Research OutputNov 05 2009In response to the call for a science of science policy, we discuss the contribution of indicators at the macro-level of nations from a scientometric perspective. In addition to global trends such as the rise of China, one can relate percentages of world ... More

Is the United States losing ground in science? A global perspective on the world science systemNov 05 2009Based on the Science Citation IndexExpanded webversion, the USA is still by far the strongest nation in terms of scientific performance. Its relative decline in percentage share of publications is largely due to the emergence of China and other Asian ... More

Propagation of Quantum Expectations with Husimi FunctionsJul 31 2012Mar 17 2013We analyse the dynamics of expectation values of quantum observables for the time-dependent semiclassical Schr\"odinger equation. To benefit from the positivity of Husimi functions, we switch between observables obtained from Weyl and Anti-Wick quantization. ... More

Generalized Fréchet Bounds for Cell Entries in Multidimensional Contingency TablesAug 09 2017Nov 20 2017We consider the lattice, $\mathcal{L}$, of all subsets of a multidimensional contingency table and establish the properties of monotonicity and supermodularity for the marginalization function, $n(\cdot)$, on $\mathcal{L}$. We derive from the supermodularity ... More

Shifted set families, degree sequences, and plethysmOct 26 2006Jan 10 2008We study, in three parts, degree sequences of k-families (or k-uniform hypergraphs) and shifted k-families. The first part collects for the first time in one place, various implications such as: Threshold implies Uniquely Realizable implies Degree-Maximal ... More

Evolution of eccentricity and orbital inclination of migrating planets in 2:1 mean motion resonanceJun 09 2014We determine, analytically and numerically, the conditions needed for a system of two migrating planets trapped in a 2:1 mean motion resonance to enter an inclination-type resonance. We provide an expression for the asymptotic equilibrium value that the ... More

Eccentricity pumping of a planet on an inclined orbit by a discJan 05 2010In this paper, we show that the eccentricity of a planet on an inclined orbit with respect to a disc can be pumped up to high values by the gravitational potential of the disc, even when the orbit of the planet crosses the disc plane. This process is ... More

Quasi-classical description of molecular dynamics based on Egorov's theoremMay 28 2014Oct 23 2014Egorov's theorem on the classical propagation of quantum observables is related to prominent quasi-classical descriptions of quantum molecuar dynamics as the linearized semiclassical initial value representation (LSC-IVR), the Wigner phase space method ... More

A database of high and medium-resolution stellar spectraJan 22 2001We present a database of 908 spectra of 709 stars obtained with the ELODIE spectrograph at Observatoire de Haute-Provence. 52 orders of the echelle spectra have been carefully fitted together to provide continuous, high-resolution spectra in the wavelength ... More

A fast partial parse of natural language sentences using a connectionist methodMar 22 1995The pattern matching capabilities of neural networks can be used to locate syntactic constituents of natural language. This paper describes a fully automated hybrid system, using neural nets operating within a grammatic framework. It addresses the representation ... More

Elemental abundances as a function of kinematics in the Milky Way's diskJan 20 2006We present the results of our investigation of three samples kinematically representative of the thin and thick disks and the Hercules stream using the catalogue of Soubiran & Girard (2005). We have observed abundance trends and age distribution of each ... More

The Second Quantized Quantum Turing Machine and Kolmogorov ComplexityJun 30 2005Apr 05 2008The Kolmogorov complexity of a physical state is the minimal physical resources required to reproduce that state. We define a second quantized quantum Turing machine and use it to define second quantized Kolmogorov complexity. There are two advantages ... More

Modernity of Halphen's variations on a theme of MongeFeb 14 2016We construct a Z_3-slice to the natural action of PGL(V) on the variety of smooth arcs in the projective space P(V).

Pleating coordinates for the Teichmüller space of a punctured torusJan 01 1992We construct new coordinates for the Teichm\"uller space Teich of a punctured torus into $\bold{R} \times\bold{R}^+$. The coordinates depend on the representation of Teich as a space of marked Kleinian groups $G_\mu$ that depend holomorphically on a parameter ... More

Rotational Invariance, Phase Relationships and the Quantum Entanglement IllusionDec 16 1999Another Bell test "loophole" - imperfect rotational invariance - is explored, and novel realist ideas on parametric down-conversion as used in recent "quantum entanglement" experiments are presented. The usual quantum theory of entangled systems assumes ... More

Subtraction of ``accidentals'' and the validity of Bell testsMar 18 1999Apr 21 1999In some key Bell experiments, including two of the well-known ones by Alain Aspect, 1981-2, it is only after the subtraction of ``accidentals'' from the coincidence counts that we get violations of Bell tests. The data adjustment, producing increases ... More

Design of Cooperative Processes in a Customer-Supplier Relationship: An Approach Based on Simulation and Decision TheoryOct 22 2008Performance improvement in supply chains, taking into account customer demand in the tactical planning process is essential. It is more and more difficult for the customers to ensure a certain level of demand over a medium term horizon as their own customers ... More

Model theoretic properties of the Urysohn sphereJan 09 2014Apr 08 2015We characterize model theoretic properties of the Urysohn sphere as a metric structure in continuous logic. In particular, our first main result shows that the theory of the Urysohn sphere is $\text{SOP}_n$ for all $n\geq 3$, but does not have the fully ... More

Direct reconstruction of dark energyFeb 26 2010May 04 2010An important issue in cosmology is reconstructing the effective dark energy equation of state directly from observations. With so few physically motivated models, future dark energy studies cannot only be based on constraining a dark energy parameter ... More

Timing and Other Artifacts in EPR ExperimentsApr 29 1997Re-evaluation of the evidence (some of it unpublished) shows that experimenters conducting Einstein-Podolsky-Bohm (EPR) experiments may have been deceived by various pre-conceptions and artifacts. False or unproven assumptions were made regarding, in ... More

Coupling charge-exchange vibrations to nucleons in a relativistic framework: effect on Gamow-Teller transitions and beta-decay half-livesJun 04 2018Nov 22 2018The nuclear response theory for isospin-transfer modes in the relativistic particle-vibration coupling framework is extended to include coupling of single nucleons to isospin-flip (charge-exchange) phonons, in addition to the usual neutral vibrations. ... More

Quasiparticle-vibration coupling effects on nuclear transitions of astrophysical interestSep 11 2017The relativistic quasiparticle time-blocking approximation (RQTBA) is applied to the description of nuclear excitation modes of astrophysical interest. This method is based on the meson-nucleon Lagrangian and goes beyond the standard relativistic quasiparticle ... More

An extremal graph problem with a transcendental solutionJul 26 2016Aug 04 2016We prove that the number of multigraphs with vertex set $\{1, \ldots, n\}$ such that every four vertices span at most nine edges is $a^{n^2 + o(n^2)}$ where $a$ is transcendental (assuming Schanuel's conjecture from number theory). This is an easy consequence ... More

Endo-trivial modules for finite groups with dihedral Sylow 2-subgroupJul 06 2015Aug 04 2015Let $k$ be an algebraically closed field of characteristic $p>0$ and $G$ a finite group. We provide a description of the torsion subgroup $TT(G)$ of the finitely generated abelian group $T(G)$ of endo-trivial $kG$-modules when $p=2$ and $G$ has a dihedral ... More

Limits of limit sets IJul 05 2011We show that for a strongly convergent sequence of geometrically finite Kleinian groups with geometrically finite limit, the Cannon-Thurston maps of limit sets converge uniformly. If however the algebraic and geometric limits differ, as in the well known ... More

Simple modules in the Auslander-Reiten quiver of principal blocks with abelian defect groupsFeb 17 2017Feb 21 2017Given an odd prime $p$, we investigate the position of simple modules in the stable Auslander-Reiten quiver of the principal block of a finite group with non-cyclic abelian Sylow $p$-subgroups. In particular, we prove a reduction to finite simple groups. ... More

Loading Monotonicity of Weighted Premiums, and Total Positivity Properties of Weight FunctionsJun 10 2018Feb 21 2019We consider the construction of insurance premiums that are monotonically increasing with respect to a loading parameter. By introducing weight functions that are totally positive of higher order, we derive higher monotonicity properties of weighted transformed ... More

QoS Guaranteed Energy Minimization Over Two-Way Relaying NetworksDec 13 2015Nov 16 2016In this work, we consider a typical three-node, two-way relaying network (TWRN) over fading channels. The aim is to minimize the entire system energy usage for a TWRN in the long run, while satisfying the required average symmetric exchange rate between ... More

[alpha/Fe] in the thin and the thick disk towards an automatic parametrization of stellar spectraNov 10 2004We test an automatic procedure to measure [Fe/H] and [alpha/Fe] on high resolution spectra. The test sample is the intersection of the ELODIE library and a catalogue of 830 stars having well determined abundances.

Density Evolution for SUDOKU Codes on the Erasure ChannelJul 16 2014Codes based on SUDOKU puzzles are discussed, and belief propagation decoding introduced for the erasure channel. Despite the non-linearity of the code constraints, it is argued that density evolution can be used to analyse code performance due to the ... More

Evaluating Parsing Schemes with Entropy IndicatorsSep 22 1997This paper introduces an objective metric for evaluating a parsing scheme. It is based on Shannon's original work with letter sequences, which can be extended to part-of-speech tag sequences. It is shown that this regular language is an inadequate model ... More

Vortices and black holes in dilatonic gravityJun 25 1999Apr 11 2000We study analytically black holes pierced by a thin vortex in dilatonic gravity for an arbitrary coupling of the vortex to the dilaton in an arbitrary frame. We show that the horizon of the charged black hole supports the long-range fields of the Nielsen-Olesen ... More

Chip-firing and energy minimization on M-matricesMar 07 2014Nov 21 2014We consider chip-firing dynamics defined by arbitrary M-matrices. M-matrices generalize graph Laplacians and were shown by Gabrielov to yield avalanche finite systems. Building on the work of Baker and Shokrieh, we extend the concept of energy minimizing ... More

Recurrence on Affine GrassmanniansMar 31 2017We study the action of the affine group $G$ of $\mathbb{R}^d$ on the space $X_{k,\,d}$ of $k$-dimensional affine subspaces. Given a compactly-supported Zariski dense probability measure $\mu$ on $G$, we show that $X_{k,\,d}$ supports a $\mu$-stationary ... More

Endotrivial modules for the Schur covers of the symmetric and alternating groupsMar 16 2015Mar 24 2015We investigate the endotrivial modules for the Schur covers of the symmetric and alternating groups and determine the structure of their group of endotrivial modules in all characteristics. We provide a full description of this group by generators and ... More

Simple endotrivial modules for linear, unitary and exceptional groupsJan 02 2015Motivated by a recent result of Robinson showing that simple endotrivial modules essentially come from quasi-simple groups we classify such modules for finite special linear and unitary groups as well as for exceptional groups of Lie type. Our main tool ... More

Portfolio optimization with insider's initial information and counterparty riskAug 27 2012We study the gain of an insider having private information which concerns the default risk of a counterparty. More precisely, the default time \tau is modelled as the first time a stochastic process hits a random barrier L. The insider knows this barrier ... More

Spacetime structure of the global vortexAug 05 2002Aug 25 2002We analyse the spacetime structure of the global vortex and its maximal analytic extension in an arbitrary number of spacetime dimensions. We find that the vortex compactifies space on the scale of the Hubble expansion of its worldvolume, in a manner ... More

Cosmology in Brans-Dicke theory with a scalar potentialNov 27 1996We consider the general behaviour of cosmologies in Brans-Dicke theory where the dilaton is self-interacting via a potential $V(\Phi)$. We show that the general radiation universe is a two-dimensional dynamical system whereas the dust or false vacuum ... More

Endotrivial modules for the sporadic simple groups and their coversFeb 20 2015Mar 25 2015In a step towards the classification of endotrivial modules for quasi-simple groups, we investigate endotrivial modules for the sporadic simple groups and their covers. A main outcome of our study is the existence of torsion endotrivial modules with dimension ... More

Part-products of $S$-restricted integer compositionsMar 11 2012If $S$ is a cofinite set of positive integers, an "$S$-restricted composition of $n$" is a sequence of elements of $S$, denoted $\vec{\lambda}=(\lambda_1,\lambda_2,...)$, whose sum is $n$. For uniform random $S$-restricted compositions, the random variable ... More

Cloud computing and hyperbolic Voronoi diagrams on the sphereMar 13 2012In this work we study the minimization problem for the total distance in a cloud computing network on the sphere. We give a solution to this problem in terms of hyperbolic Voronoi diagrams on the sphere. We present results of computer simulations illustrating ... More

Homodyne detection and optical parametric amplification: a classical approach applied to proposed "loophole-free" Bell testsDec 17 2005Recent proposed ``loophole-free'' Bell tests are discussed in the light of classical models for the relevant features of optical parametric amplification and homodyne detection. The Bell tests themselves are uncontroversial: there are no obvious loopholes ... More

Timing, ``Accidentals'' and Other Artifacts in EPR ExperimentsNov 20 1997Nov 25 1997Subtraction of ``accidentals'' in Einstein-Podolsky-Rosen experiments frequently changes results compatible with local realism into ones that appear to demonstrate non-locality. The validity of the procedure depends on the unproven assumption of the independence ... More

Star Formation and AGN Activity in Interacting Galaxies: A Near-UV PerspectiveOct 18 2013We study nearby galaxies in close pairs to study the key factors affecting star formation and AGN activity triggered during galaxy interactions. Close pairs are selected from the Sloan Digital Sky Survey assuming a projected separation of $<$30kpc and ... More