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A Massive Magnetic Helium Atmosphere White Dwarf Binary in a Young Star ClusterJun 11 2019We have searched the Gaia DR2 catalogue for previously unknown hot white dwarfs in the direction of young open star clusters. The aim of this experiment was to try and extend the initial-final mass relation (IFMR) to somewhat higher masses, potentially ... More

A Search for Unresolved Double Degenerates Using IUE ArchivesMar 08 2005We present preliminary results of a study aimed at detecting double white dwarf systems using a method based on a comparison of optical and UV spectra for 141 DA stars drawn from the IUE archives. In particular, we are looking for dicrepancies between ... More

Integral quantizations with two basic examplesAug 10 2013Nov 22 2013The paper is devoted to integral quantization, a procedure based on operator-valued measure and resolution of the identity. We insist on covariance properties in the important case where group representation theory is involved. We also insist on the inherent ... More

Open Questions for operators related to Rectangular Catalan CombinatoricsMar 14 2016Mar 20 2016We formulate many open questions regarding the Schur positivity of the effect of interesting operators on symmetric functions, and give supporting evidence for why one should expect such behavior.

The White Dwarf Companions of 56 Per and HR 3643Dec 18 1995We have obtained low-dispersion IUE spectra of the stars 56 Persei (F4 V) and HR 3643 (F7 II), as part of a survey of late-type stars with a 1565 A flux excess in the TD-1 ultraviolet sky survey. The IUE spectrum of each star reveals the presence of a ... More

On the Spectral Evolution of Helium-Atmosphere White Dwarfs Showing Traces of HydrogenMar 15 2018We present a detailed spectroscopic analysis of 115 helium-line (DB) and 28 cool, He-rich hydrogen-line (DA) white dwarfs based on atmosphere fits to optical spectroscopy and photometry. We find that 63% of our DB population show hydrogen lines, making ... More

Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius RelationSep 07 2017We present a detailed spectroscopic and photometric analysis of 219 DA and DB white dwarfs for which trigonometric parallax measurements are available. Our aim is to compare the physical parameters derived from the spectroscopic and photometric techniques, ... More

Spectroscopic Analysis of the White Dwarf KUV 02196+2816: A New Unresolved DA+DB Degenerate BinaryFeb 20 2009A spectroscopic analysis of the DBA (or DAB) white dwarf KUV 02196+2816 is presented. The observed hydrogen and helium line profiles are shown to be incompatible with model spectra calculated under the assumption of a homogeneous hydrogen and helium chemical ... More

To what extent are canonical and coherent state quantizations physically equivalent?Feb 17 2011Nov 14 2012We investigate the consistency of coherent state (or Berezin-Klauder-Toeplitz, or anti-Wick) quantization in regard to physical observations in the non- relativistic (or Galilean) regime. We compare this procedure with the canonical quantization (on both ... More

Know Your Neighborhood: A Detailed Model Atmosphere Analysis of Nearby White DwarfsFeb 24 2012We present improved atmospheric parameters of nearby white dwarfs lying within 20 pc of the Sun. The aim of the current study is to obtain the best statistical model of the least-biased sample of the white dwarf population. A homogeneous analysis of the ... More

A Spectroscopic Survey & Analysis of Bright, Hydrogen-Rich White DwarfsSep 14 2011Oct 04 2011We have conducted a spectroscopic survey of over 1300 bright (V < 17.5), hydrogen-rich white dwarfs based largely on the last published version of the McCook & Sion catalog. The complete results from our survey, including the spectroscopic analysis of ... More

Primordial gravitational waves in a quantum model of big bounceSep 18 2017Apr 12 2018We quantise and solve the dynamics of gravitational waves in a quantum Friedmann-Lemaitre-Robertson-Walker spacetime filled with perfect fluid. The classical model is formulated canonically. The Hamiltonian constraint is de-parametrised by setting a fluid ... More

Coloured peak algebras and Hopf algebrasMay 27 2005For $G$ a finite abelian group, we study the properties of general equivalence relations on $G_n=G^n\rtimes \SG_n$, the wreath product of $G$ with the symmetric group $\SG_n$, also known as the $G$-coloured symmetric group. We show that under certain ... More

A Hopf algebra of subword complexesAug 06 2015We introduce a Hopf algebra structure of subword complexes, including both finite and infinite types. We present an explicit cancellation free formula for the antipode using acyclic orientations of certain graphs, and show that this Hopf algebra induces ... More

Vibronic framework for quantum mixmaster universeDec 01 2015Dec 03 2015Following our previous papers concerning the quantization of the vacuum Bianchi-IX model within or beyond the Born-Oppenheimer and adiabatic approximation, we develop a more elaborate analysis of the dynamical properties of the model based the vibronic ... More

Smooth Big Bounce from Affine QuantizationMay 03 2013Jan 28 2014We examine the possibility of dealing with gravitational singularities on a quantum level through the use of coherent state or wavelet quantization instead of canonical quantization. We consider the Robertson-Walker metric coupled to a perfect fluid. ... More

Smooth Bounce in Affine Quantization of Bianchi IJan 30 2015We present the affine coherent state quantization of the Bianchi I model. As in our previous paper on quantum theory of Friedmann models, we employ a variable associated with a perfect fluid to play a role of clock. Then we deparameterize the model. A ... More

Nonadiabatic bounce and an inflationary phase in the quantum mixmaster universeNov 18 2015Jun 24 2016Following our previous paper, Bergeron et al, Smooth quantum dynamics of the mixmaster universe, Phys. Rev. D 92, 061302(R) (2015), concerning the quantization of the vacuum Bianchi IX model and the Born-Huang-Oppenheimer framework, we present a further ... More

Interlaced rectangular parking functionsMar 13 2015The aim of this work is to extend to a general $S_m\times S_n$-module context the Grossman-Bizley paradigm that allows the enumeration of Dyck paths in a $m\times n$-rectangle. We obtain an explicit formula for the the "bi-Frobenius" characteristic of ... More

Hypergraphic polytopes: combinatorial properties and antipodeDec 23 2017In an earlier paper, the first two authors defined orientations on hypergraphs. Using this definition we provide an explicit bijection between acyclic orientations in hypergraphs and faces of hypergraphic polytopes. This allows us to obtain a geometric ... More

Hopf monoids from class functions on unitriangular matricesMar 07 2012Oct 16 2012We build, from the collection of all groups of unitriangular matrices, Hopf monoids in Joyal's category of species. Such structure is carried by the collection of class function spaces on those groups, and also by the collection of superclass function ... More

A non-commutative generalization of $k$-Schur functionsApr 07 2008We introduce non-commutative analogues of $k$-Schur functions of Lapointe-Lascoux and Morse. We give an explicit formulas for the expansions of non-commutive functions with one and two parameters in terms of these new functions. These results are similar ... More

Hopf dreamsJul 09 2018Jul 27 2018This paper introduces a Hopf algebra structure on a family of reduced pipe dreams. We show that this Hopf algebra is free and cofree, and construct a surjection onto a commutative Hopf algebra of permutations. The pipe dream Hopf algebra contains Hopf ... More

Eigenfunctions and Random Waves in the Benjamini-Schramm limitOct 12 2018We investigate the asymptotic behavior of eigenfunctions of the Laplacian on Riemannian manifolds. We show that Benjamini-Schramm convergence provides a unified language for the level and eigenvalue aspects of the theory. As a result, we present a mathematically ... More

Fan realizations of subword complexes and multi-associahedra via Gale dualityApr 29 2014Aug 04 2014We present complete simplicial fan realizations of any spherical subword complex of type $A_n$ for $n\leq 3$. This provides complete simplicial fan realizations of simplicial multi-associahedra $\Delta_{2k+4,k}$, whose facets are in correspondence with ... More

Quantizations from (P)OVM'sOct 11 2013We explain the powerful role that operator-valued measures can play in quantizing any set equipped with a measure, for instance a group (resp. group coset) with its invariant (resp. quasi-invariant) measure. Coherent state quantization is a particular ... More

Weyl-Heisenberg integral quantization(s): a compendiumMar 24 2017We present a list of formulae useful for Weyl-Heisenberg integral quantizations, with arbitrary weight, of functions or distributions on the plane. Most of these formulae are known, others are original. The list encompasses particular cases like Weyl-Wigner ... More

Inequalities between Littlewood-Richardson CoefficientsMar 31 2004We prove that a conjecture of Fomin, Fulton, Li, and Poon, associated to ordered pairs of partitions, holds for many infinite families of such pairs. We also show that the bounded height case can be reduced to checking that the conjecture holds for a ... More

An upper bound for the volumes of complements of periodic geodesicsDec 08 2014May 10 2016A periodic geodesic on a surface has a natural lift to the unit tangent bundle; when the complement of this lift is hyperbolic, its volume typically grows as the geodesic gets longer. We give an upper bound for this volume which is linear in the geometric ... More

Singularity avoidance in a quantum model of the Mixmaster universeJan 30 2015Dec 12 2015We present a quantum model of the vacuum Bianchi-IX dynamics. It is based on four main elements. First, we use a compound quantization procedure: an affine coherent state quantization for isotropic variables and a Weyl quantization for anisotropic ones. ... More

Identifying and Characterizing New Nearby White DwarfsOct 31 2006How confident are we that all of the nearest white dwarfs (WDs) have been identified? In an effort to answer this question, we have begun an initiative to identify and characterize new nearby WDs, particularly in the southern hemisphere. We estimate physical ... More

Smooth Quantum Dynamics of Mixmaster UniverseJan 09 2015We present a quantum version of the vacuum Bianchi IX model by implementing affine coherent state quantization combined with a Born-Oppenheimer-like adiabatic approximation. The analytical treatment is carried out on both quantum and semiclassical levels. ... More

Three examples of quantum dynamics on the half-line with smooth bouncingAug 21 2017Aug 31 2017This article is an introductory presentation of the quantization of the half-plane based on affine coherent states (ACS). The half-plane is viewed as the phase space for the dynamics of a positive physical quantity evolving with time, and its affine symmetry ... More

A baby Majorana quantum formalismJan 15 2017Jun 03 2017The aim of the present paper is to introduce and to discuss the most basic fundamental concepts of quantum physics by means of a simple and pedagogical example. An appreciable part of its content presents original results. We start with the Euclidean ... More

On ergodic two-armed banditsMay 04 2009Apr 26 2012A device has two arms with unknown deterministic payoffs and the aim is to asymptotically identify the best one without spending too much time on the other. The Narendra algorithm offers a stochastic procedure to this end. We show under weak ergodic assumptions ... More

The number of generations entirely visited for recurrent random walks on random environmentDec 16 2011In this paper we are interested in a random walk in a random environment on a super-critical Galton-Watson tree. We focus on the recurrent cases already studied by Y. Hu and Z. Shi and G. Faraud. We prove that the largest generation entirely visited by ... More

Asymptotic expansions of Laplace integrals for quantum state tomographyJul 04 2016Bayesian estimation of a mixed quantum state can be approximated via maximum likelihood (MaxLike) estimation when the likelihood function is sharp around its maximum. Such approximations rely on asymptotic expansions of multi-dimensional Laplace integrals. ... More

A q-Analog of Foulke's conjectureFeb 25 2016Jul 01 2016We propose a $q$-analog of classical plethystic conjectures due to Foulkes. In our conjectures, a divided difference of plethysms of Hall-Littlewood polynomials $H_n(\mathbf{x};q)$ replaces the analogous difference of plethysms of complete homogeneous ... More

Bounded Height Interlaced Pairs of Parking FunctionsApr 27 2015We enumerate interlaced pairs of parking functions whose underlying Dyck path has a bounded height. We obtain an explicit formula for this enumeration in the form of a quotient of analogs of Chebicheff polynomials having coefficients in the ring of symmetric ... More

Grothendieck bialgebras, Partition lattices and symmetric functions in noncommutative variablesJun 17 2005We show that the Grothendieck bialgebra of the semi-tower of partition lattice algebras is isomorphic to the graded dual of the bialgebra of symmetric functions in noncommutative variables. In particular this isomorphism singles out a canonical new basis ... More

Spread of visited sites of a random walk along the generations of a branching processMar 13 2013Feb 13 2014In this paper we consider a null recurrent random walk in random environment on a super-critical Galton-Watson tree. We consider the case where the log-Laplace transform $\psi$ of the branching process satisfies $\psi(1)=\psi'(1)=0$ for which G. Faraud, ... More

La conjecture des sous-groupes de surfaces (d'après Jeremy Kahn et Vladimir Markovic)Jul 13 2012This is the text of my Bourbaki seminar on the proof of the surface subgroup conjecture by Jeremy Kahn and Vladimir Markovic.

Produits dans la cohomologie des variétés arithmétiques : quelques calculs sur les séries thêtaDec 15 2006For abelian varieties $A$, in the most interesting cohomology theories $H^* (A)$ is the exterior algebra of $H^1(A)$. In this paper we study a weak generalization of this in the case of arithmetic manifolds associated to orthogonal or unitary groups. ... More

Représentations cohomologiques isolées, applications cohomologiquesNov 28 2005We give a new proof of a Theorem of Vogan which classify the cohomological representations of a real semisimple Lie group $G$ which are isolated in the unitary dual of $G$. We investigate the same question in the automorphic dual, and obtain partial results. ... More

The Halo White Dwarf WD 0346+246 RevisitedMay 18 2001The extreme helium-rich atmospheric composition determined for the halo white dwarf WD 0346+246 is reexamined. This solution is shown to be improbable from an astrophysical point of view when accretion of hydrogen and metals from the interstellar medium ... More

The topology of nilpotent representations in reductive groups and their maximal compact subgroupsOct 18 2013Aug 06 2014Let G be a complex reductive linear algebraic group and let K be a maximal compact subgroup of G. Given a nilpotent group \Gamma generated by r elements, we consider the representation spaces Hom(\Gamma,G) and Hom(\Gamma,K) with the natural topology induced ... More

Yukawa Textures and AnomaliesDec 29 1994We augment the Minimal Supersymmetric Standard Model with a gauged family-dependent $U(1)$ to reproduce Yukawa textures compatible with experiment. In the simplest model with one extra chiral electroweak singlet field, acceptable textures require this ... More

Combinatorial Cellular Decompositions for the Space of Complex Coefficient PolynomialsJan 26 2009May 05 2011We describe a classification of degree n complex coefficient polynomials with respect to combinatorial patterns that arise from the two real algebraic curves obtained as the zero sets for their real and imaginary part. In particular, we work out explicitly ... More

Propriétés de Lefschetz automorphes pour les groupes unitaires et orthogonauxMar 03 2005Let $G$ be a connected semisimple group over ${\Bbb Q}$. Given a maximal compact subgroup and a convenient arithmetic subgroup $\Gamma\subset G({\Bbb Q})$, one constructs an arithmetic manifold $S=S(\Gamma)=\Gamma\backslash X$. If $H\subset G$ is a connected, ... More

Tentative d'épuisement de la cohomologie d'une variété de Shimura par restriction à ses sous-variétésMar 24 2004Let $G$ be a connected semisimple group over ${\Bbb Q}$. Given a maximal compact subgroup $K\subset G({\Bbb R})$ such that $X=G({\Bbb R})/K$ is a Hermitian symmetric domain, and a convenient arithmetic subgroup $\Gamma\subset G({\Bbb Q})$, one constructs ... More

A Critical Examination of Halo White Dwarf CandidatesNov 26 2002A detailed analysis of halo white dwarf candidates is presented, which is based on model atmosphere fits to observed energy distributions built from photoelectric or photographic magnitudes. Most of the candidates identified in reduced proper motion diagrams ... More

New Formulas and Conjectures for the Nabla OperatorMay 29 2011The operator nabla, introduced by Garsia and the author, plays a crucial role in many aspect of the study of diagonal harmonics. Besides giving several new formulas involving this operator, we show how one is lead to representation theoretic explanations ... More

Multivariate Diagonal Coinvariant Spaces for Complex Reflection GroupsMay 22 2011Nov 02 2011For finite complex reflexion groups, we consider the graded $W$-modules of diagonally harmonic polynomials in $r$ sets of variables, and show that associated Hilbert series may be described in a global manner, independent of the value of $r$.

Convergence of normalized Betti numbers in nonpositive curvatureNov 06 2018Feb 04 2019We study the convergence of volume-normalized Betti numbers in Benjamini-Schramm convergent sequences of non-positively curved manifolds with finite volume. In particular, we show that if $X$ is an irreducible symmetric space of noncompact type, $X \neq ... More

Combinatorics of r-Dyck paths, r-Parking functions, and the r-Tamari latticesFeb 28 2012Mar 03 2012This paper's aim is to present recent combinatorial considerations on r-Dyck paths, r-Parking functions, and the r-Tamari lattices. Giving a better understanding of the combinatorics of these objects has become important in view of their (conjectural) ... More

Cohomologie $L^p$ et pincementJul 24 2012A sharp vanishing theorem for the $L^p$ cohomology torsion of Riemannian manifolds with pinched negative curvature is given. It follows that certain negatively curved homogeneous spaces cannot be quasiisometric to better pinched manifolds.

Pincement du plan hyperbolique complexeMar 23 2011$L^p$-cohomology of rank one symmetric spaces of noncompact type is shown to be Hausdorff for values of $p$ where this does not follow from curvature pinching. Using the multiplicative structure on $L^p$-cohomology, it is shown that no simply connected ... More

Submanifolds and differential forms on Carnot manifolds, after M. Gromov and M. RuminApr 21 2016The purpose of these notes is to explain parts of Gromov's survey of Carnot-Carathedory spaces, in the light of subsequent results of M. Rumin. Among the rich material provided by Gromov, most of which pertains to analysis on metric spaces, we choose ... More

Light propagation in inhomogeneous and anisotropic cosmologiesNov 10 2015The standard model of cosmology is based on the hypothesis that the Universe is spatially homogeneous and isotropic. When interpreting most observations, this cosmological principle is applied stricto sensu: the light emitted by distant sources is assumed ... More

Rheological properties of dense granular flowsMar 18 2015Recent progresses in understanding the behavior of dense granular flows are presented. After presenting a bulk rheology of granular materials, I focus on the new developments to account for non-local effects, and on ongoing research concerning the surface ... More

Teaching Leśniewski's Prothetic with a Natural Deduction SystemJul 14 2015Protothetic is one of the most stimulating systems for propositional logic. Including quantifiers and an inference rule for definitions, it is a very interesting mean for the study of many questions of metalogic. Unfortunately, it only exists in an axiomatic ... More

Intelligent escalation and the principle of relativityMay 27 2015Escalation is the fact that in a game (for instance in an auction), the agents play forever. The $0,1$-game is an extremely simple infinite game with intelligent agents in which escalation arises. It shows at the light of research on cognitive psychology ... More

Twisted spectral geometry for the standard modelMar 25 2015The Higgs field is a connection one-form as the other bosonic fields, provided one describes space no more as a manifold M but as a slightly non-commutative generalization of it. This is well encoded within the theory of spectral triples: all the bosonic ... More

Dependent Types for Extensive GamesNov 18 2016Extensive games are tools largely used in economics to describe decision processes of a community of agents. In this paper we propose a formal presentation based on the proof assistant Coq which focuses mostly on infinite extensive games and their characteristics. ... More

Super-Quantum, Non-Signaling Correlations Cannot ExistFeb 02 2016May 28 2016Non-local correlations stronger than quantum correlations between two non-signaling systems cannot exist. The reason is that any physically realizable PR-box that would give rise to such correlations requires to be described in a non-commutative, quantum-like ... More

Fortuitous sequences of flips of the top of a stack of n burnt pancakes for all n>24Jan 23 2016Burnt pancakes problem was defined by Gates and Papadimitriou in 1979. A stack S of pancakes with a burnt side must be sorted by size, the smallest on top, and each pancake with burnt side down. Only operation allowed is to split stack in two parts and ... More

The risk of divergenceDec 22 2015We present infinite extensive strategy profiles with perfect information and we show that replacing finite by infinite changes the notions and the reasoning tools. The presentation uses a formalism recently developed by logicians and computer science ... More

Sawtooth models and asymptotic independence in large compositionsJan 26 2015In this paper we improve the probabilistic approach to compositions of Ehrenborg, Levin and Readdy by introducing a simpler but more general probabilistic model. As consequence we get some new estimates on the behavior of a uniform random permutation ... More

Study of clustering structures through breakup reactionsDec 16 2014Models for the description of breakup reactions used to study the structure of exotic cluster structures like halos are reviewed. The sensitivity of these models to the projectile description is presented. Calculations are sensitive to the projectile ... More

Generic family with robustly infinitely many sinksNov 24 2014Sep 29 2015We show, for every $r>d\ge 0$ or $r=d\ge 2$, the existence of a Baire generic set of $C^d$-families of $C^r$-maps $(f_a)_{a\in (-1,1)^k}$ of a manifold $M$ of dimension $\ge 2$, so that for every $a$ small the map $f_a$ has infinitely many sinks. When ... More

Some noncoherent, nonpositively curved Kähler groupsOct 30 2014If $\Gamma$ is any nonuniform lattice in the group ${\rm PU}(2,1)$, let $\overline{\Gamma}$ be the quotient of $\Gamma$ obtained by filling the cusps of $\Gamma$ (i.e. killing the center of parabolic subgroups). Assuming that such a lattice $\Gamma$ has ... More

Infinitary Intersection Types as Sequences: a New Answer to Klop's QuestionOct 20 2016We provide a type-theoretical characterization of weakly-normalizing terms in an infinitary lambda-calculus. We adapt for this purpose the standard quantitative (with non-idempotent intersections) type assignment system of the lambda-calculus to our infinite ... More

Emergence and non-typicality of the finiteness of the attractors in many topologiesSep 28 2016We will introduce the notion of Emergence for a dynamical system, and we will conjecture the local typicality of super-polynomial ones. Then, as part of this program, we will provide sufficient conditions for an open set of Cd-families of Cr-dynamics ... More

Dynamics of non-equilibrium membrane bud formationApr 08 2003Dec 09 2003The dynamical response of a lipid membrane to a local perturbation of its molecular symmetry is investigated theoretically. A density asymmetry between the two membrane leaflets is predominantly released by in-plane lipid diffusion or membrane curvature, ... More

Very Strong Disorder for the Parabolic Anderson model in low dimensionsDec 19 2012We study the free energy of the Parabolic Anderson Model, a time-continuous model of directed polymers in random environment. We prove that in dimension 1 and 2, the free energy is always negative, meaning that very strong disorder always holds. The result ... More

Cepheid distances from InterferometrySep 14 2005Long baseline interferometry is now able to resolve the pulsational change of the angular diameter of a significant number of Cepheids in the solar neighborhood. This allows the application of a new version of the Baade-Wesselink (BW) method to measure ... More

Structured matrices and inversesMar 16 2008A matrix (and any associated linear system) will be referred to as structured if it has a small displacement rank. It is known that the inverse of a structured matrix is structured, which allows fast inversion (or solution), and reduced storage requirements. ... More

On the zeroes of the Alexander polynomial of a Lorenz knotOct 19 2011Jul 16 2014We show that the zeroes of the Alexander polynomial of a Lorenz knot all lie in some annulus whose width depends explicitly on the genus and the braid index of the considered knot.

Les noeuds de LorenzApr 16 2009Oct 07 2011This article is a survey on Lorenz knots. We describe the original construction, prove several classical properties, in particular the fact that the closure of a positive braid is a fibered knot, and describe Ghys'correspondance between modular knots ... More

Finite size effects on surface excess quantities: application to crystal growth and surface melting of epitaxial layersSep 03 2004From a macroscopic viewpoint phase transitions as surface melting or growth mode can be described in term of Gibbs excess quantity duly amended by size effect. The aim of this study is to consider such amended quantities to describe surface melting and ... More

Masaki Kashiwara and Algebraic AnalysisOct 27 2008This paper is a brief overview of the main contributions of Masaki Kashiwara in the domain of microlocal and algebraic analysis.

Paths and partitions: combinatorial descriptions of the parafermionic statesMar 20 2009Jun 12 2009The Z_k parafermionic conformal field theories, despite the relative complexity of their modes algebra, offer the simplest context for the study of the bases of states and their different combinatorial representations. Three bases are known. The classic ... More

Open problems for the superKdV equationsMay 03 2000After a review of the basic results concerning the $N=1,2$ supersymmetric extensions of the Korteweg-de Vries equation, with a pedagogical presentation of the superspace techniques, we discuss some basic open problems mainly in relation with the N=2 extensions. ... More

Feasibility of 3D reconstructions from a single 2D diffraction measurementSep 09 2009Jan 18 2010We comment on the recent manuscript by Raines et al. [arXiv:0905.0269v2] (now published in Nature, vol. 463, p. 214-217, 2010), which suggests that in certain conditions a single diffraction measurement may be sufficient to reconstruct the full three-dimensional ... More

Persistence of normally expanded submanifolds with boundary or cornersMar 24 2008We show that invariant submanifolds with boundary, and more generally with corners which are normally expanded by an endomorphism are persistent as $a$-regular stratifications. This result will be shown in class $C^s$, for $s\ge 1$. We present also a ... More

About the origins of the Supersymmetric Standard ModelJul 22 2001Could one use supersymmetry to relate the fermions, constituants of matter, with the bosons messengers of the interactions? This is, ideally, what a symmetry between fermions and bosons would be expected to do. However many obstacles seemed, long ago, ... More

The BE-Higgs boson as spin-0 partner of the Z, in the Supersymmetric Standard ModelMay 31 2014Supersymmetric extensions of the standard model lead to gauge/BE-Higgs unification by providing spin-0 bosons as extra states for spin-1 gauge bosons within massive gauge multiplets. They may be described by the spin-0 components of massive gauge superfields ... More

Invisible Upsilon decays into Light Dark MatterOct 14 2009Mar 12 2010Invisible psi and Upsilon decays into light neutralinos, within the MSSM or N(n)MSSM, are smaller than for nu nubar production, even if light spin-0 particles are coupled to quarks and neutralinos. In a more general way, light dark matter particles are ... More

Constraints on Light Dark Matter and U bosons, from psi, Upsilon, K+, pi0, eta and eta' decaysJul 28 2006Following searches for photinos and very light gravitinos in invisible decays of psi and Upsilon, we discuss new limits on Light Dark Matter and U bosons, from psi and Upsilon decays, as well as rare decays of K+ and invisible decays of pi0, eta and eta' ... More

Bornes effectives pour la torsion des courbes elliptiques sur les corps des nombresApr 02 1996We give an effective form of the theorem of Mazur-Kamienny-Merel on the torsion of elliptic curves over number fields.

Kinetic walks for samplingMar 01 2019The persistent walk is a classical model in kinetic theory, which has also been studied as a toy model for MCMC questions. Its continuous limit, the telegraph process, has recently been extended to various velocity jump processes (Bouncy Particle Sampler, ... More

On the Flatland ParadoxMay 01 2015Apr 07 2017We revisit the flatland paradox proposed by \cite{ston1976} which is an example of non-conglomerability. The aim of the paper is to show that the improperness of the prior is not directly involved in the inconsistency. First, we show that the choice of ... More

Infinite divisibility of solutions to some self-similar integro-differential equations and exponential functionals of Lévy processesMay 16 2006Nov 09 2009We provide the increasing eigenfunctions associated to spectrally negative self-similar Feller semigroups, which have been introduced by Lamperti. These eigenfunctions are expressed in terms of a new family of power series which includes, for instance, ... More

Critical points of pairs of varieties of algebrasOct 14 2008For a class V of algebras, denote by Conc(V) the class of all semilattices isomorphic to the semilattice Conc(A) of all compact congruences of A, for some A in V. For classes V1 and V2 of algebras, we denote by crit(V1,V2) the smallest cardinality of ... More

Superrigidité géométrique et applications harmoniquesDec 23 2006Jan 05 2007These are expanded notes of a course given in Grenoble in june 2004. After a brief description of the harmonic map proof of Margulis' superrigidity and arithmeticity theorems, it is shown how the method might generalize to fundamental groups of simplicial ... More

A note on Fisher Information hypocoercive decay for the linear Boltzmann equationMar 30 2017Aug 01 2017This note deals with the linear Boltzmann equation in the non-compact setting with a confining potential which is close to quadratic. We prove that in this case, starting from a smooth initial datum, the Fisher Information (hence, the relative entropy) ... More

Quelques plats pour la métrique de HoferApr 19 2007Aug 22 2007We show, by an elementary and explicit construction, that the group of Hamiltonian diffeomorphisms of certain symplectic manifolds, endowed with Hofer's metric, contains subgroups quasi-isometric to Euclidean spaces of arbitrary dimension.

Cramér's theorem in measurable locally convex spacesMar 22 2011We give a general setting for Cram\'er's large deviations theorem for the empirical means of a sequence of i.i.d. random vectors, which contains Cram\'er's theorem in a Banach space and Sanov's theorem. ----- Nous \'etablissons un cadre g\'en\'eral pour ... More

On the Hodge theory of stratified spacesMar 14 2016This article is a survey of recent work of the author, together with Markus Banagl, Eric Leichtnam, Rafe Mazzeo, and Paolo Piazza, on the Hodge theory of stratified spaces. We discuss how to resolve a Thom-Mather stratified space to a manifold with corners ... More

Weak-strong uniqueness for the isentropic compressible Navier-Stokes systemJul 17 2008We prove weak-strong uniqueness results for the isentropic compressible Navier-Stokes system on the torus. In other words, we give conditions on a strong solution so that it is unique in a class of weak solutions. Known weak-strong uniqueness results ... More