Results for "Vincent Roulet"

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Learning with Clustering StructureJun 16 2015Sep 19 2016We study supervised learning problems using clustering constraints to impose structure on either features or samples, seeking to help both prediction and interpretation. The problem of clustering features arises naturally in text classification for instance, ... More
Integration Methods and Accelerated Optimization AlgorithmsFeb 22 2017We show that accelerated optimization methods can be seen as particular instances of multi-step integration schemes from numerical analysis, applied to the gradient flow equation. In comparison with recent advances in this vein, the differential equation ... More
A Smoother Way to Train Structured Prediction ModelsFeb 08 2019We present a framework to train a structured prediction model by performing smoothing on the inference algorithm it builds upon. Smoothing overcomes the non-smoothness inherent to the maximum margin structured prediction objective, and paves the way for ... More
Sharpness, Restart and AccelerationFeb 13 2017The {\L}ojasievicz inequality shows that sharpness bounds on the minimum of convex optimization problems hold almost generically. Here, we show that sharpness directly controls the performance of restart schemes. The constants quantifying sharpness are ... More
Beyond the Standard ModelDec 28 2001May 07 2007The successes and shortcomings of the Standard Model are reviewed, with emphasis on the reasons motivating the need to extend it. The basic elements of grand unification and supersymmetry are described, exploring their phenomenological implications for ... More
Renegar's Condition Number and Compressed Sensing PerformanceJun 10 2015Renegar's condition number is a data-driven computational complexity measure for convex programs, generalizing classical condition numbers in linear systems. We provide evidence that for a broad class of compressed sensing problems, the worst case value ... More
Computational Complexity versus Statistical Performance on Sparse Recovery ProblemsJun 10 2015Nov 02 2018We show that several classical quantities controlling compressed sensing performance directly match classical parameters controlling algorithmic complexity. We first describe linearly convergent restart schemes on first-order methods solving a broad range ... More
Rigidity dependent knee and cosmic ray induced high energy neutrino fluxesJun 30 2003Scenarios in which the knee of the cosmic ray spectrum depends on the particle rigidities usually predict that the cosmic ray composition becomes heavier above the knee and have associated a change in the spectral slope of each individual nuclear component ... More
Quantum synchronization and entanglement generationJun 26 2018Aug 08 2018We study synchronization in a two-node network built out of the smallest possible self-sustained oscillator: a spin 1. We first demonstrate that phase locking between the quantum oscillators can be achieved, even for limit cycles that cannot be synchronized ... More
Comment on "On the Origin of the Highest Energy Cosmic Rays"Jun 18 1998We show that the photodisintegration of heavy cosmic ray nuclei with energies above 10^20 eV is dominated by interactions with photons from the cosmic microwave background radiation, rather than from infrared ones. This implies that the observed air shower ... More
Anisotropies of ultra-high energy cosmic rays diffusing from extragalactic sourcesDec 04 2013We obtain the dipolar anisotropies in the arrival directions of ultra-high energy cosmic rays diffusing from nearby extragalactic sources. We discuss both the energy regime of spatial diffusion and the quasi-rectilinear one leading to just angular diffusion ... More
CP violation in scatterings, three body processes and the Boltzmann equations for leptogenesisJul 03 2007Sep 17 2007We obtain the Boltzmann equations for leptogenesis including decay and scattering processes with two and three body initial or final states. We present an explicit computation of the CP violating scattering asymmetries. We analyze their possible impact ... More
Neutrinos in physics and astrophysicsOct 18 1999An elementary general overview of the neutrino physics and astrophysics is given. We start by a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why ... More
Revealing the work cost of generalized thermal bathsSep 14 2018We derive the work cost of using generalized thermal baths from the physical equivalence of quantum mechanics under unitary transformations. We demonstrate our method by considering a qubit extracting work from a single bath to amplify a cavity field. ... More
Latest results from the Pierre Auger ObservatoryJan 10 2011Recent results obtained with the Pierre Auger Observatory are described. These include measurements of the spectrum, anisotropies and composition of ultra-high energy cosmic rays. The ankle of the spectrum is measured at $4\times 10^{18}$~eV and a suppression ... More
Neutrino AstrophysicsNov 30 2000Dec 04 2000A general overview of neutrino physics and astrophysics is given, starting with a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why it is so important ... More
Astroparticle Theory: Some New Insights into High Energy Cosmic RaysOct 14 2003Some new developments obtained in the last few years concerning the propagation of high energy cosmic rays are discussed. In particular, it is shown how the inclusion of drift effects in the transport diffusion equations leads naturally to an explanation ... More
Quantum Rotor EnginesApr 30 2018This chapter presents autonomous quantum engines that generate work in the form of directed motion for a rotor. We first formulate a prototypical clock-driven model in a time-dependent framework and demonstrate how it can be translated into an autonomous ... More
Neutrino PhenomenologyDec 27 2004A general overview of neutrino physics is given, starting with a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why it is so important to establish ... More
Microlensing searches of dark matterApr 25 2000The evolution of the observational results of microlensing towards the LMC and some of the suggested interpretations to account for them are discussed. It is emphasized that the results at present are indicative of a lensing population of white dwarfs, ... More
Reconstructing compositionsOct 16 2006We consider the problem of reconstructing compositions of an integer from their subcompositions, which was raised by Raykova (albeit disguised as a question about layered permutations). We show that every composition w of n\ge 3k+1 can be reconstructed ... More
Constraints on $Λ(t)$-cosmology with power law interacting dark sectorsMay 30 2012May 31 2012Motivated by the cosmological constant and the coincidence problems, we consider a cosmological model where the cosmological constant $\Lambda_0$ is replaced by a cosmological term $\Lambda(t)$ which is allowed to vary in time. More specifically, we are ... More
Simple physics of the partly pinned fluid systemsMay 12 2014Sep 08 2014In this paper, we consider some aspects of the physics of the partly pinned (PP) systems obtained by freezing in place particles in equilibrium bulk fluid configurations in the normal (nonglassy) state. We first discuss the configurational overlap and ... More
Statistical mechanics of homogeneous partly pinned fluid systemsJun 24 2010Dec 05 2010The homogeneous partly pinned fluid systems are simple models of a fluid confined in a disordered porous matrix obtained by arresting randomly chosen particles in a one-component bulk fluid or one of the two components of a binary mixture. In this paper, ... More
Definability of types over finite partial order indiscerniblesAug 11 2011In this paper, we show that a partitioned formula \phi is dependent if and only if \phi has uniform definability of types over finite partial order indiscernibles. This generalizes our result from a previous paper [1]. We show this by giving a decomposition ... More
Semantic Vector MachinesMay 14 2011We first present our work in machine translation, during which we used aligned sentences to train a neural network to embed n-grams of different languages into an $d$-dimensional space, such that n-grams that are the translation of each other are close ... More
Gluon Mass, Glueballs and Gluonic MesonsFeb 18 2011We review the phenomenological and theoretical evidences for dynamical gluon mass generation and the main features of the glueball spectrum in (pure gauge) Yang-Mills theories. The mixing between glueball and conventional $\bar q q$ states in $f_0$ scalar ... More
Philosophy in the Face of Artificial IntelligenceMay 19 2016In this article, I discuss how the AI community views concerns about the emergence of superintelligent AI and related philosophical issues.
Cosmic anisotropies from quasars: from polarization to structural-axis alignmentsApr 18 2016The comparison of the orientations of the optical-polarization vectors of quasars that are separated by billions of light-years has led to the discovery that they are aligned instead of pointing in random directions as expected. This discovery has been ... More
The Joint Physics Analysis Center WebsiteJan 08 2016The Joint Physics Analysis Center is a collaboration between theorists and experimentalists working in hadronic physics. In order to facilitate the exchange of information between the different actors in hadron spectroscopy, we created an interactive ... More
Approximation of stochastic processes by non-expansive flows and coming down from infinityNov 23 2015May 25 2016We approximate stochastic processes in finite dimension by dynamical systems. We provide trajectorial estimates which are uniform with respect to the initial condition for a well chosen distance. This relies on some non-expansivity property of the flow, ... More
Growth rates of permutation classes: from countable to uncountableMay 13 2016Sep 05 2016We establish that there is an algebraic number $\xi\approx 2.30522$ such that while there are uncountably many growth rates of permutation classes arbitrarily close to $\xi$, there are only countably many less than $\xi$. Central to the proof are various ... More
Dessins d'enfants for analystsApr 01 2015We present an algorithmic way of exactly computing Belyi functions for hypermaps and triangulations in genus 0 or 1, and the associated dessins, based on a numerical iterative approach initialized from a circle packing combined with subsequent lattice ... More
Mean-field microrheology of a very soft colloidal suspension: inertia induces shear-thickeningMar 03 2015Apr 27 2015Colloidal suspensions have a rich rheology and can exhibit shear-thinning as well as shear-thickening. Numerical simulations recently suggested that shear-thickening may be attributed to the inertia of the colloids, besides the hydrodynamic interactions ... More
A new test of uniformity for object orientations in astronomyJul 20 2015We briefly present a new coordinate-invariant statistical test dedicated to the study of the orientations of transverse quantities of non-uniformly distributed sources on the celestial sphere. These quantities can be projected spin-axes or polarization ... More
Why are tensor field theories asymptotically free?Jul 15 2015In this pedagogic letter we explain the combinatorics underlying the generic asymptotic freedom of tensor field theories. We focus on simple combinatorial models with a $1/p^2$ propagator and quartic interactions and on the comparison between the intermediate ... More
Estimates for Weierstrass division in ultradifferentiable classesNov 26 2015Mar 23 2016We study the Weierstrass division theorem for function germs in strongly non-quasianalytic Denjoy-Carleman classes $\mathcal{C}_M$. For suitable divisors $P(x,t)=x^d+a_1(t)x^{d-1}+\cdots+a_d(t)$ with real-analytic coefficients $a_j$, we show that the ... More
Gradient trajectories for plane singular metrics I: oscillating trajectoriesMay 30 2012We construct an example of a real plane analytic singular metric, degenerating only at the origin, such that any gradient trajectory (respectively to this singular metric) of some well chosen function spirals around the origin. The inversion mapping carries ... More
Numerical Simulations of the Ising Model on the Union Jack LatticeJan 26 2011The Ising model is famous model for magnetic substances in Statistical Physics, and has been greatly studied in many forms. It was solved in one-dimension by Ernst Ising in 1925 and in two-dimensions without an external magnetic field by Lars Onsager ... More
The metric completion of the Riemannian space of Kähler metricsJan 30 2014Apr 09 2014Let $X$ be a compact K\"ahler manifold and $\a \in H^{1,1}(X,\R)$ a K\"ahler class. We study the metric completion of the space $\HH_\a$ of K\"ahler metrics in $\a$, when endowed with the Mabuchi $L^2$-metric $d$. Using recent ideas of Darvas, we show ... More
Fonctorial Construction of Frobenius CategoriesMar 16 2009Let $\Ascr,\Bscr$ be exact categories with $\Ascr$ karoubian and $M$ be an exact functor. Under suitable adjonction hypotheses for $M$, we are able to show that the direct factors of the objects of $\Ascr$ of the form $MY$ with $Y \in \Bscr$ make up a ... More
A very short proof of Forester's rigidity resultJan 24 2003May 22 2003The deformation space of a simplicial G-tree T is the set of G-trees which can be obtained from T by some collapse and expansion moves, or equivalently, which have the same elliptic subgroups as T. We give a short proof of a rigidity result by Forester ... More
Abelianization of Subgroups of Reflection Group and their Braid Group; an Application to CohomologyMar 03 2010Aug 31 2010The final result of this article gives the order of the extension $$\xymatrix{1\ar[r] & P/[P,P] \ar^{j}[r] & B/[P,P] \ar^-{p}[r] & W \ar[r] & 1}$$ as an element of the cohomology group $H^2(W,P/[P,P])$ (where $B$ and $P$ stands for the braid group and ... More
On the non-extendability of quasianalytic germsJun 21 2010Sep 07 2010Let $\mathcal{E}_1(M)^+$ be the local ring of germs at 0 of functions belonging to a given Denjoy-Carleman quasianalytic class in a neighborhood of 0 in $[0,+\infty[$. We show that the ring $\mathcal{E}_1(M)^+$ contains elements that cannot be extended ... More
Conic intersections, Maximal Cohen-Macaulay modules and the Four Subspace problemFeb 21 2017Mar 10 2017Let $X$ be a set of $4$ generic points in $\mathbb{P}^2$ with homogeneous coordinate ring $R$. We classify indecomposable graded MCM modules over $R$ by reducing the classification to the Four Subspace problem solved by Nazarova and Gel$'$fand-Ponomarev, ... More
Shtukas for reductive groups and Langlands correspondence for function fieldsMar 10 2018We discuss recent developments in the Langlands program for function fields, and in the geometric Langlands program. In particular we explain a canonical decomposition of the space of cuspidal automorphic forms for any reductive group G over a function ... More
Brick polytopes, lattice quotients, and Hopf algebrasMay 28 2015Nov 30 2017This paper is motivated by the interplay between the Tamari lattice, J.-L. Loday's realization of the associahedron, and J.-L. Loday and M. Ronco's Hopf algebra on binary trees. We show that these constructions extend in the world of acyclic $k$-triangulations, ... More
Electron neutrino opacity in magnetised mediaNov 03 1997We study the effects of strong magnetic fields ($B> 10^{13}$~G) in the cross section for $\nu_e n\to p e$ scattering in the presence of a degenerate electron background. This can be relevant for the $\nu_e$ propagation in the proto-neutron star stage ... More
Supersymmetric radiative corrections to neutrino indices of refractionJun 02 1995We compute the one-loop effects on the neutrino propagation through matter induced by virtual supersymmetric particles. We show that, in the minimal version of the supersymmetric standard model, a non-degeneracy between sleptons of the second and third ... More
Eliciting Single-Peaked Preferences Using Comparison QueriesJan 15 2014Voting is a general method for aggregating the preferences of multiple agents. Each agent ranks all the possible alternatives, and based on this, an aggregate ranking of the alternatives (or at least a winning alternative) is produced. However, when there ... More
Prediction Markets, Mechanism Design, and Cooperative Game TheoryMay 09 2012Prediction markets are designed to elicit information from multiple agents in order to predict (obtain probabilities for) future events. A good prediction market incentivizes agents to reveal their information truthfully; such incentive compatibility ... More
Cohomologie de de Rham entiere (Integral de Rham cohomology)Apr 06 2004Apr 06 2004The Cartier isomorphism allows a nice description of the Bockstein spectral sequence of the de Rham complex over the integers. It is used to compute the integral de Rham cohomology of affine spaces. ----- On decrit la suite spectrale de Bockstein issue ... More
X- and Gamma-Ray Line Emission ProcessesAug 21 2002This chapter is intended to provide a general presentation of the atomic and nuclear processes responsible for X-ray line and gamma-ray line emission in various astrophysical environments. I consider line production from hot plasmas, from accelerated ... More
Can the coincidence problem be solved by a cosmological model of coupled dark energy and dark matter?Jul 23 2013Oct 12 2014Motivated by the cosmological constant and the coincidence problems, we consider a cosmological model where the dark sectors are interacting together through a phenomenological decay law $\dot{\rho}_{\Lambda}=Q\rho_{\Lambda}^n$ in a FRW spacetime with ... More
Baryon acoustic signature in the clustering of density maximaJun 02 2008Oct 22 2008We reexamine the two-point correlation of density maxima in Gaussian initial conditions. Spatial derivatives of the linear density correlation, which were ignored in the calculation of Bardeen, Bond, Kaiser & Szalay (1986), are included in our analysis. ... More
Environmental dependence in the ellipsoidal collapse modelJul 31 2007May 15 2008N-body simulations have demonstrated a correlation between the properties of haloes and their environment. In this paper, we assess whether the ellipsoidal collapse model can produce a similar dependence. First, we explore the statistical correlation ... More
Proof of the Tadic conjecture U0 on the unitary dual of GL(m,D)Feb 01 2007Let F be a non-Archimedean local field of characteristic 0, and let D be a finite dimensional central division algebra over F. We prove that any unitary irreducible representation of a Levi subgroup of GL(m,D), with m a positive integer, induces irreducibly ... More
Simultaneous double transformations of functions depending on space and timeNov 13 2013May 01 2014It is shown that performing simultaneously two transformations on functions of space and time (for instance a Fourier transform on the space variable and a Laplace transform on the time variable) can be easier than performing them one after the other ... More
Group analysis of an ideal plasticity modelJan 05 2012In this paper, we study the Lie point symmetry group of a system describing an ideal plastic plane flow in two dimensions in order to find analytical solutions of the system. The infinitesimal generators that span the Lie algebra for this system are obtained, ... More
Remplissage De L'Espace Euclidien Par Des Complexes PolyÉdriques D'Orientation ImposÉe Et De RotonditÉ UniformeDec 26 2008We build polyhedral complexes in Rn that coincide with dyadic grids with different orientations, while keeping uniform lower bounds (depending only on n) on the flatness of the added polyhedrons including their subfaces in all dimensions. After the definitions ... More
Diffusion of a particle quadratically coupled to a thermally fluctuating fieldFeb 09 2013Apr 19 2013We study the diffusion of a Brownian particle quadratically coupled to a thermally fluctuating field. In the weak coupling limit, a path-integral formulation allows to compute the effective diffusion coefficient in the cases of an active particle, that ... More
On the trace and norm maps from $Γ_0(\mathfrak{p})$ to $\operatorname{GL}_2(A)$Jun 16 2014Let $f$ be a Drinfeld modular form for $\Gamma_0(\mathfrak{p})$. From such a form, one can obtain two forms for the full modular group $\operatorname{GL}_2(A)$: by taking the trace or the norm from $\Gamma_0(\mathfrak{p})$ to $\operatorname{GL}_2(A)$. ... More
An Erdős--Hajnal analogue for permutation classesNov 03 2015Feb 09 2016Let $\mathcal{C}$ be a permutation class that does not contain all layered permutations or all colayered permutations. We prove that there is a constant $c$ such that every permutation in $\mathcal{C}$ of length $n$ contains a monotone subsequence of ... More
Comptage de représentations cuspidales congruentesJul 09 2015Let $F$ be a non-Archimedean locally compact field of residue characteristic $p$, $G$ be an inner form of $GL_n(F)$, $n\ge1$, and $\ell$ be a prime number different from $p$. We give a numerical criterion for an integral $\ell$-adic irreducible cuspidal ... More
The multilayer shallow water system in the limit of small density contrastJul 08 2015Jan 19 2016We study the inviscid multilayer Saint-Venant (or shallow-water) system in the limit of small density contrast. We show that, under reasonable hyperbolicity conditions on the flow and a smallness assumption on the initial surface deformation, the system ... More
Semi-simple Lie groups acting conformally on compact Lorentz manifoldsJun 29 2015We give a classification, up to local isomorphisms, of semi-simple Lie groups without compact factors that can act faithfully and conformally on a compact Lorentz manifold of dimension greater than or equal to $3$.
On the torsion part in the K-theory of imaginary quadratic fieldsApr 08 2015May 21 2015We obtain upper bounds for the torsion in the $K$-groups of the ring of integers of imaginary quadratic number fields, in terms of their discriminants.
Universal Jamison spaces and Jamison sequences for $C_0$-semigroupsMar 04 2015An increasing sequence of positive integers $(n_k)_{k\ge 0}$ is said to be a Jamison sequence if the following property holds true: for every separable complex Banach space $X$ and every $T\in \mathcal{B}(X)$ which is partially power-bounded with respect ... More
Rewriting Higher-Order Stack TreesFeb 16 2015Higher-order pushdown systems and ground tree rewriting systems can be seen as extensions of suffix word rewriting systems. Both classes generate infinite graphs with interesting logical properties. Indeed, the model-checking problem for monadic second ... More
Space-time domain velocity distributions in isotropic radiative transfer in two dimensionsAug 29 2016We compute the exact solutions of the radiative transfer equation in two dimensions for isotropic scattering. The intensity and the radiance are given in the space-time domain for isotropic and unidirectional sources. These analytical results are compared ... More
Description and simulation of physics of Resistive Plate ChambersJul 26 2016Monte-Carlo simulation of physical processes is an important tool for detector development as it allows to predict signal pulse amplitude and timing, time resolution, efficiency ... Yet despite the fact they are very common, full simulations for RPC-like ... More
Weierstrass points on the Drinfeld modular curve $X_0(\mathfrak{p})$Sep 26 2014Apr 15 2015Consider the Drinfeld modular curve $X_0(\mathfrak{p})$ for $\mathfrak{p}$ a prime ideal of $\mathbb{F}_q[T]$. It was previously known that if $j$ is the $j$-invariant of a Weierstrass point of $X_0(\mathfrak{p})$, then the reduction of $j$ modulo $\mathfrak{p}$ ... More
On Hessian limit directions along non-oscillating gradient trajectoriesMar 03 2011Given a non-oscillating gradient trajectory G of a real analytic function f, we show that the limit v of the secants at the limit point O of G along the trajectory G is an eigen-vector of the limit of the direction of the Hessian matrix Hess (f) at O ... More
Flatness, preorders and general metric spaces (revised)Feb 21 2006We use a generic notion of flatness in the enriched context to define various completions of metric spaces -- enrichments over [0,\infty] -- and preorders -- enrichments over 2. We characterize the weights of colimits commuting in [0,\infty] with the ... More
Flatness, preorders and general metric spacesSep 12 2003This paper studies a general notion of flatness in the enriched context: P-flatness where the parameter P stands for a class of presheaves. One obtains a completion of a category A by considering the category Flat_P(A) of P-flat presheaves over A. This ... More
Energy conservation and dissipation properties of time-integration methods for the nonsmooth elastodynamics with contactOct 09 2014This research report is devoted to the study of the conservation and the dissipation properties of the mechanical energy of several time--integration methods dedicated to the elasto--dynamics with unilateral contact. Given that the direct application ... More
Introduction to chtoucas for reductive groups and to the global Langlands parameterizationApr 25 2014Sep 17 2015This is a translation in English of version 3 of the article arXiv:1404.3998, which is itself an introduction to arXiv:1209.5352. We explain all the ideas of the proof of the following theorem. For any reductive group G over a global function field, we ... More
On quasianalytic local ringsSep 13 2005Feb 07 2008This expository article is devoted to the local theory of ultradifferentiable classes of functions, with a special emphasis on the quasianalytic case. Although quasianalytic classes are well-known in harmonic analysis since several decades, their study ... More
Banach KK-theory and the Baum-Connes conjectureApr 22 2003The report below describes the applications of Banach KK-theory to a conjecture of P. Baum and A. Connes about the K-theory of group $C^*$-algebras, and a new proof of the classification by Harish-Chandra, the construction by Parthasarathy and the exhaustion ... More
On a model for the storage of files on a hardware I : Statistics at a fixed time and asymptoticsNov 14 2006Jan 24 2008We consider a generalized version in continuous time of the parking problem of Knuth. Files arrive following a Poisson point process and are stored on a hardware identified with the real line. We specify the distribution of the space of unoccupied locations ... More
A Devastating Example for the Halfer RuleOct 17 2016How should we update de dicto beliefs in the face of de se evidence? The Sleeping Beauty problem divides philosophers into two camps, halfers and thirders. But there is some disagreement among halfers about how their position should generalize to other ... More
Limit groups and groups acting freely on R^n-treesJun 20 2003Nov 29 2004We give a simple proof of the finite presentation of Sela's limit groups by using free actions on R^n-trees. We first prove that Sela's limit groups do have a free action on an R^n-tree. We then prove that a finitely generated group having a free action ... More
Which nestohedra are removahedra?Jul 09 2014Oct 13 2014A removahedron is a polytope obtained by deleting inequalities from the facet description of the classical permutahedron. Relevant examples range from the associahedra to the permutahedron itself, which raises the natural question to characterize which ... More
Propriétés ergodiques des applications rationnellesNov 10 2006This is a survey article with focus on the following problem. Given $f:X \to X$ a meromorphic endomorphism of some compact K\"ahler manifold $X$, construct and study - under natural numerical conditions - a canonical invariant probability measure with ... More
Hausdorff dimensions for SLE_6Apr 16 2002Mar 30 2005We prove that the Hausdorff dimension of the trace of SLE_6 is almost surely 7/4 and give a more direct derivation of the result (due to Lawler-Schramm-Werner) that the dimension of its boundary is 4/3. We also prove that, for all \kappa<8, the SLE_{\kappa} ... More
A mass for ALF manifoldsMar 19 2008Mar 20 2008We prove positive mass theorems on ALF manifolds, i.e. complete noncompact manifolds that are asymptotic to a circle fibration over a Euclidean base, with fibers of asymptotically constant length.
Exact computation of the CDF of the Euclidean distance between a point and a random variable uniformly distributed in disks, balls, or polyhedrons and application to PSHAMay 30 2014Aug 19 2014We consider a random variable expressed as the Euclidean distance between an arbitrary point and a random variable uniformly distributed in a closed and bounded set of a three-dimensional Euclidean space. Four cases are considered for this set: a union ... More
Is a Finite Intersection of Balls Covered by a Finite Union of Balls in Euclidean Spaces ?Apr 18 2018Sep 24 2018Considering a finite intersection of balls and a finite union of other balls in an Euclidean space, we propose an exact method to test whether the intersection is covered by the union. We reformulate this problem into quadratic programming problems. For ... More
Symmetry group analysis of an ideal plastic flowFeb 11 2011In this paper, we study the Lie point symmetry group of a system describing an ideal plastic plane flow in two dimensions in order to find analytical solutions. The infinitesimal generators that span the Lie algebra for this system are obtained. We completely ... More
On VC-minimal fields and dp-smallnessJul 30 2013In this paper, we show that VC-minimal ordered fields are real closed. We introduce a notion, strictly between convexly orderable and dp-minimal, that we call dp-small, and show that this is enough to characterize many algebraic theories. For example, ... More
A speedy pixon image reconstruction algorithmDec 03 1999A speedy pixon algorithm for image reconstruction is described. Two applications of the method to simulated astronomical data sets are also reported. In one case, galaxy clusters are extracted from multiwavelength microwave sky maps using the spectral ... More
Permutation classes of every growth rate above 2.48188Jul 17 2008Jun 22 2009We prove that there are permutation classes (hereditary properties of permutations) of every growth rate (Stanley-Wilf limit) at least \lambda \approx 2.48187, the unique real root of x^5-2x^4-2x^2-2x-1, thereby establishing a conjecture of Albert and ... More
A sharp bound for the reconstruction of partitionsJun 23 2008Answering a question of Cameron, Pretzel and Siemons proved that every integer partition of $n\ge 2(k+3)(k+1)$ can be reconstructed from its set of $k$-deletions. We describe a new reconstruction algorithm that lowers this bound to $n\ge k^2+2k$ and present ... More
A Contribution to the Theory Behind the Capture-Recapture M0 Model: An Improved EstimatorNov 21 2012Feb 17 2014We explore the use of a sufficient statistic based on the data of samples that are selected under the M_0 capture-recapture closed population model (Schwarz and Seber, 1999). A Rao-Blackwellized version of the estimator based on a sufficient statistic ... More
Mode-coupling theory predictions for the dynamical transitions of the partly pinned fluid systemsOct 04 2011The predictions of the mode-coupling theory (MCT) for the dynamical arrest scenarios in a partly pinned (PP) fluid system are reported. The corresponding dynamical phase diagram is found to be very similar to that of a related quenched-annealed (QA) system. ... More
Aging, rejuvenation and memory : the example of spin glassesMar 22 2006In this paper, we review the general features of the out-of-equilibrium dynamics of spin glasses. We use this example as a guideline for a brief description of glassy dynamics in other disordered systems like structural and polymer glasses, colloids, ... More
Core and intersection number for group actions on treesJul 12 2004Jul 21 2004We present the construction of some kind of "convex core" for the product of two actions of a group on $\bbR$-trees. This geometric construction allows to generalize and unify the intersection number of two curves or of two measured foliations on a surface, ... More
Mixed State Hall Effect in a Twinned YBa2Cu3O7-d Single CrystalJul 06 1999Thanks to the 9 contacts deposited on the surface of a high quality YBCO twinned single crystal, we investigate both vortex guided motion along twins and the mixed state Hall effect. Firstly, we clearly identify the vortex phase transition and show that, ... More
On volumes of quasi-arithmetic hyperbolic latticesMar 23 2016Apr 09 2016We prove that the covolume of any quasi-arithmetic hyperbolic lattice (a notion that generalizes the definition of arithmetic subgroups) is a rational multiple of the covolume of an arithmetic subgroup. As a corollary, we obtain a good description for ... More
Random Tensors and Quantum GravityMar 23 2016Jul 15 2016We provide an informal introduction to tensor field theories and to their associated renormalization group. We focus more on the general motivations coming from quantum gravity than on the technical details. In particular we discuss how asymptotic freedom ... More