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Submillimeter - sized proximity effect in graphite and bismuthFeb 08 2019In this work, we probe the electrical properties of macroscopic graphite and bismuth in which the electrical current is injected via superconducting electrodes, few millimeters apart from each other. Results reveal the induction of a partial superconducting-like ... More

The future of stellar occultations by distant solar system bodies: perspectives from the Gaia astrometry and the deep sky surveysMar 02 2019Distant objects in the solar system are crucial to better understand the history and evolution of its outskirts. The stellar occultation technique allows the determination of their sizes and shapes with kilometric accuracy, a detailed investigation of ... More

Partial Order on the set of Boolean Regulatory FunctionsJan 22 2019Logical models have been successfully used to describe regulatory and signaling networks without requiring quantitative data. However, existing data is insufficient to adequately define a unique model, rendering the parametrization of a given model a ... More

Discovering heavy U(1)-gauged Higgs bosons at the HL-LHCMar 06 2019We determine the discovery potential of the Large Hadron Collider (LHC) at 13 TeV center-of-mass energy for a heavy scalar resonance in the dilepton channel. In particular, we consider the singlet-like heavy mass eigenstate of a mixed two Higgs doublet ... More

Lambda and Antilambda polarization in Au-Au collisions at RHICDec 20 2007Jun 02 2010Recent experiments at RHIC have shown that in 200 GeV Au-Au collisions, the Lambda and Antilambda hyperons are produced with very small polarizations [1], almost consistent with zero. These results can be understood in terms of a model that we recently ... More

Average Free-Energy of Directed Polymers and Interfaces in Random MediaSep 22 2016We consider first the field theory formulation for a directed polymer in the presence of a quenched disorder. To obtain the average free-energy of this system we use the distributional zeta-function method. The distributional zeta-function is a complex ... More

Unstable and elusive superconductorsMay 28 2015We briefly review earlier and report original experimental results in the context of metastable or possible superconducting materials. We show that applied electric field induces conducting state in Copper Chloride (CuCl) whose characteristics resemble ... More

Sivashinsky equation in a rectangular domainFeb 13 2007May 12 2007The (Michelson) Sivashinsky equation of premixed flames is studied in a rectangular domain in two dimensions. A huge number of 2D stationary solutions are trivially obtained by addition of two 1D solutions. With Neumann boundary conditions, it is shown ... More

Type Ia SupernovaeMar 22 2000Type Ia Supernovae are in many aspects still enigmatic objects. Recent years have witnessed a bonanza of supernova observations. The increased samples from dedicated searches have allowed the statistical investigation of Type Ia Supernovae as a class. ... More

On the equivalence between minimal sufficient statistics, minimal typical models and initial segments of the Halting sequenceNov 23 2009It is shown that the length of the algorithmic minimal sufficient statistic of a binary string x, either in a representation of a finite set, computable semimeasure, or a computable function, has a length larger than the computational depth of x, and ... More

Algebra+Homotopy=OperadFeb 15 2012This survey provides an elementary introduction to operads and to their applications in homotopical algebra. The aim is to explain how the notion of an operad was prompted by the necessity to have an algebraic object which encodes higher homotopies. We ... More

Dualite de Koszul des PROPsMay 04 2004In this thesis, we generalize the Koszul duality for associative algebras and operads to PROPs. The operads are algebraic objects that represent the operations with multiple inputs but only one output acting on a certain type of algebras. A PROP models ... More

Complexity of PL-manifoldsOct 30 2008Apr 14 2009We extend Matveev's complexity of 3-manifolds to PL compact manifolds of arbitrary dimension, and we study its properties. The complexity of a manifold is the minimum number of vertices in a simple spine. We study how this quantity changes under the most ... More

Order and chaos in quantum irregular scattering: Wigner's time delayMar 12 1993Recent developments in the semiclassical analysis of chaotic systems are reviewed and illustrated for Wigner's time delay in elastic scattering of a point particle from three disks in the plane. The convergence of the cycle expanded periodic orbit expression ... More

Search for the Standard Model Higgs boson decaying to four lepton (muon, electron) final states with the ATLAS experiment at the LHC colliderAug 01 2008The search for the Standard Model Higgs boson in the four lepton (electron and muon) final state with the ATLAS detector at the LHC is presented. The analysis strategy and the efficiency for selecting the signal and rejecting the background are discussed, ... More

The full faithfulness conjectures in characteristic pSep 19 2012We present a triangulated version of the conjectures of Tate and Beilinson on algebraic cycles over a finite field. This sheds a new light on Lichtenbaum's Weil-etale cohomology.

Algebraic tori as Nisnevich sheaves with transfersJul 25 2011Mar 13 2012We relate R-equivalence on tori with Voevodsky's theory of homotopy invariant Nisnevich sheaves with transfers and effective motivic complexes.

A sheaf-theoretic reformulation of the Tate conjectureJan 06 1998Let p be a prime number. We give a conjecture of a sheaf-theoretic nature which is equivalent to the strong form of the Tate conjecture for smooth, projective varieties X over F_p: for all n>0, the order of pole of the Hasse-Weil zeta function of X at ... More

Somekawa's K-groups and Voevodsky's Hom groups (preliminary version)Sep 23 2010We construct a surjective homomorphism from Somekawa's K-group associated to a finite collection of semi-abelian varieties over a perfect field to a corresponding Hom group in Voevodsky's triangulated category of effective motivic complexes.

Motivic zeta functions of motivesJun 17 2006Let K be a field of characteristic 0 and A be a rigid tensor K-linear category. Let M be a finite-dimensional object of A in the sense of Kimura-O'Sullivan. We prove that the "motivic" zeta function of M with coefficients in K\_0(A) has a functional equation. ... More

Impossibility of Spontaneously Rotating Time-Crystals: A No-Go TheoremJun 26 2013Aug 19 2013I present arguments indicating the impossibility of spontaneously rotating quantum timecrystals, as recently proposed by Frank Wilczek [arXiv:1202.2539]. In particular, I prove a No-Go Theorem, rigorously ruling out the possibility of spontaneous ground-state ... More

Berry phase effects in magnetismJun 13 2005Lecture notes published in ''Magnetism goes nano'', Lecture Manuscripts of the 36th Spring School of the Institute of Solid State Research, edited by Stefan Bluegel, Thomas Brueckel, and Claus M. Schneider (Forschungszentrum Juelich, 2005).

Theory of interlayer exchange couplingMay 03 1999This paper contains the notes of lectures on the theory of interlayer exchange coupling presented at the 30-th Ferienschule of the Institut fuer Festkoerperforschung, Forschungszentrum Juelich, March 1999.

Portfolio management under risk contraints - Lectures given at MITACS-PIMS-UBC Summer School in Risk Management and Risk SharingJun 30 2013The aim of these lectures at MITACS-PIMS-UBC Summer School in Risk Man- agement and Risk Sharing is to discuss risk controlled approaches for the pricing and hedging of financial risks. We will start with the classical dual approach for financial markets, ... More

New insights into abelian topologically massive gauge theoriesMay 23 2007Abelian topologically massive gauge theories (TMGT) provide a topological mechanism to generate mass for any p-tensor boson in any dimension. Within the Hamiltonian formulation, the embedded topological field theory (TFT) is not made manifest. We therefore ... More

On the Performance Bounds of some Policy Search Dynamic Programming AlgorithmsJun 03 2013We consider the infinite-horizon discounted optimal control problem formalized by Markov Decision Processes. We focus on Policy Search algorithms, that compute an approximately optimal policy by following the standard Policy Iteration (PI) scheme via ... More

Modular self-organizationSep 26 2006The aim of this paper is to provide a sound framework for addressing a difficult problem: the automatic construction of an autonomous agent's modular architecture. We combine results from two apparently uncorrelated domains: Autonomous planning through ... More

A motivic formula for the L-function of an abelian variety over a function fieldJan 27 2014Mar 03 2016Let $A$ be an abelian variety over the function field of a smooth projective curve $C$ over an algebraically closed field $k$. We compute the $l$-adic cohomology groups of $C$ with coefficients in the locally constant sheaf associated to $H^1(\bar A,\mathbf{Q}_l)$ ... More

The Brauer group and indecomposable (2,1)-cyclesJan 04 2014Jul 09 2015We show that the torsion in the group of indecomposable $(2,1)$-cycles on a smooth projective variety over an algebraically closed field is isomorphic to a twist of its Brauer group, away from the characteristic. In particular, this group is infinite ... More

On weak Mellin transforms, second degree characters and the Riemann hypothesisFeb 09 2015We say that a function f defined on R or Qp has a well defined weak Mellin transform (or weak zeta integral) if there exists some function $M\_f(s)$ so that we have $Mell(\phi \star f,s) = Mell(\phi,s)M\_f(s)$ for all test functions $\phi$ in $C\_c^\infty(R^*)$ ... More

Transversely affine holomorphic foliations of arbitrary codimension - INov 02 2014We study holomorphic foliations with an affine homogeneous transverse structure. We give a friendly characterization of the case of transversely affine foliations in terms of matrix valued pairs of differential forms. This leads naturally to the study ... More

Groups acting on spaces of non-positive curvatureMar 15 2016Aug 25 2016In this survey article, we present some panorama of groups acting on metric spaces of non-positive curvature. We introduce the main examples and their rigidity properties , we show the links between algebraic or analytic properties of the group and geometric ... More

Algebraic and logical descriptions of generalized treesSep 30 2016Quasi-trees generalize trees in that the unique "path" between two nodes may be infinite and have any countable order type. They are used to define the rank-width of a countable graph in such a way that it is equal to the least upper-bound of the rank-widths ... More

Pathological and Omega-transitive Representations of Free GroupsApr 25 2012Nov 13 2013Given a linear order $\Omega$ its automorphism group $\Aut(\Omega)$ forms a lattice-ordered group via pointwise order. Assuming the continuum to be a regular cardinal, we show that \emph{pathological} and \emph{$\omega$-transitive} (i.e. highly transitive) ... More

On Abel-Radon transform of locally residual currentsFeb 14 2004We give in this note a generalisation of the following theorem of Henkin and Passare : Let be Y an analytic subvariety of pure codimension p in a linearly p-concave domain U, and w a meromorphic q-form (q>0) on Y; if the Abel transform of w, which is ... More

Dehn surgery on the minimally twisted seven-chain linkAug 25 2018Feb 25 2019We classify all the exceptional Dehn surgeries on the minimally twisted chain links with six and seven components.

Tame topology of arithmetic quotients and algebraicity of Hodge lociMar 26 2018We prove that the uniformizing map of any arithmetic quotient, as well as the period map associated to any pure polarized $\mathbb{Z}$-variation of Hodge structure $\mathbb{V}$ on a smooth complex quasi-projective variety $S$, are topologically tame. ... More

Asymptotic velocities in quantum and Bohmian mechanicsJul 19 2017In this paper the relations between the asymptotic velocity operators of a quantum system and the asymptotic velocities of the associated Bohmian trajectories are studied. In particular it is proved that, under suitable conditions of asymptotic regularity, ... More

Les douze surfaces de Darboux et la trialit{é}Sep 05 2017The purpose of this article is to give a geometric interpretation to the so-called "twelve surfaces of Darboux", or "Darboux wreath", which appear by applying repeatedly certain simple transformations to a given infinitesimal isometric deformation of ... More

Complexity of 3-manifoldsMay 13 2004Jan 31 2005We give a summary of known results on Matveev's complexity of compact 3-manifolds. The only relevant new result is the classification of all closed orientable irreducible 3-manifolds of complexity 10.

Quantum Spin SystemsSep 02 2004This article is a short introduction to the general topic of quantum spin systems. After a brief sketch of the history of the subject, the standard mathematical framework for formulating problems and results in quantum spin systems is described. Then, ... More

No-arbitrage in discrete-time markets with proportional transaction costs and general information structureJan 04 2005We discuss the no-arbitrage conditions in a general framework for discrete-time models of financial markets with proportional transaction costs and general information structure. We extend the results of Kabanov and al. (2002), Kabanov and al. (2003) ... More

Modal definability based on Łukasiewicz validity relationsFeb 11 2015Nov 25 2015We study two notions of definability for classes of relational structures based on modal extensions of {\L}ukasiewicz finitely valued-logics. The main results of the paper are the equivalent of the Goldblatt - Thomason theorem for these notions of definability. ... More

Fonctions zêta et $L$ de variétés et de motifsDec 31 2015Sep 04 2016R\'edaction d'un cours de M2 donn\'e \`a Jussieu au printemps 2013. This is the write-up of a Masters course given at Jussieu in Spring 2013.

Mogami manifolds, nuclei, and 3D simplicial gravityAug 06 2016Mogami introduced in 1995 a large class of triangulated 3-dimensional pseudomanifolds, henceforth called "Mogami pseudomanifolds". He proved an exponential bound for the size of this class in terms of the number of tetrahedra. The question of whether ... More

Asymmetry of the Kolmogorov complexity of online predicting odd and even bitsJul 15 2013Jan 08 2014Symmetry of information states that $C(x) + C(y|x) = C(x,y) + O(\log C(x))$. We show that a similar relation for online Kolmogorov complexity does not hold. Let the even (online Kolmogorov) complexity of an n-bitstring $x_1x_2... x_n$ be the length of ... More

Electron Paramagnetic Resonance signature of point defects in neutron irradiated hexagonal Boron NitrideJul 14 2018Oct 08 2018Hexagonal boron nitride (h-BN) is an attractive van der Waals material for studying fluorescent defects due to its large bandgap. In this work, we demonstrate enhanced pink color due to neutron irradiation and perform electron paramagnetic resonance (EPR) ... More

Effect of structural disorder on quantum oscillations in graphiteFeb 06 2017We have studied the effect of structural disorder on the de Haas van Alphen (dHvA) and Shubnikov de Haas (SdH) quantum oscillations measured in single-crystal and highly oriented pyrolytic graphite samples at temperatures down to 30 mK and at magnetic ... More

Additivity of on-line decision complexity is violated by a linear term in the length of a binary stringAug 31 2009We show that there are infinitely many binary strings z, such that the sum of the on-line decision complexity of predicting the even bits of z given the previous uneven bits, and the decision complexity of predicting the uneven bits given the previous ... More

Infinite dimensional Riemannian symmetric spaces with fixed-sign curvature operatorApr 26 2012Oct 04 2014We associate to any Riemannian symmetric space (of finite or infinite dimension) a L$^*$-algebra, under the assumption that the curvature operator has a fixed sign. L$^*$-algebras are Lie algebras with a pleasant Hilbert space structure. The L$^*$-algebra ... More

Quelques calculs de sommes de GaussAug 13 2011We observe that the Galois action on local constants associated to Galois representations of a local field yields information on their arithmetic nature, for example provides an upper bound to their order when they are roots of unity. It also yields information ... More

Around Quillen's theorem AAug 11 2011Jul 02 2014New version, including a variant of Quillen's proof of the Solomon-Tits theorem.

On the generalised Tate conjecture for products of elliptic curves over finite fieldsJan 10 2011We prove the generalised Tate conjecture for H^3 of products of elliptic curves over finite fields, by slightly modifying an argument of M. Spiess concerning the Tate conjecture. We prove it fully if the elliptic curves run among at most 3 isogeny classes. ... More

Number of points of function fields over finite fieldsOct 14 2002Oct 30 2002This is a revised and slightly expanded version. We point out that in the previous summary, "without cohomology" should really read "almost without cohomology" because of the proof of Lemma 2, that the idea to consider effective motives divisible by the ... More

Absence of spontaneous magnetic order at non-zero temperature in one- and two-dimensional Heisenberg and XY systems with long-range interactionsMay 06 2001May 27 2002The Mermin-Wagner theorem is strengthened so as to rule out magnetic long-range order at T>0 in one- or two-dimensional Heisenberg and XY systems with long-range interactions decreasing as R^{-alpha} with a sufficiently large exponent alpha. For oscillatory ... More

Non-quantized Dirac monopoles and strings in the Berry phase of anisotropic spin systemsApr 26 2004Aug 31 2004The Berry phase of an anisotropic spin system that is adiabatically rotated along a closed circuit C is investigated. It is shown that the Berry phase consists of two contributions: (i) a geometric contribution which can be interpreted as the flux through ... More

Interlayer exchange coupling: Preasymptotic correctionsAug 10 1998Sep 03 1999In the asymptotic limit, the interlayer exchange coupling decays as $D^{-2}$, where $D$ is the spacer thickness. A systematic procedure for calculating the preasymptotic corrections, i.e., the terms of order $D^{-n}$ with $n \ge 3$, is presented. The ... More

Performance Bounds for Lambda Policy Iteration and Application to the Game of TetrisNov 05 2007Oct 11 2011We consider the discrete-time infinite-horizon optimal control problem formalized by Markov Decision Processes. We revisit the work of Bertsekas and Ioffe, that introduced $\lambda$ Policy Iteration, a family of algorithms parameterized by $\lambda$ that ... More

Nonstandard Intuitionistic InterpretationsDec 22 2015We present a notion of realizability and a functional interpretation in the context of intuitionistic logic, both incorporating nonstandard principles. The functional interpretation that we present corresponds to the intuitionistic counterpart of an interpretation ... More

Lévy mixing related to distributed order calculus, subordinators and slow diffusionsJun 18 2014May 19 2015The study of distributed order calculus usually concerns about fractional derivatives of the form $\int_0^1 \partial^\alpha u \, m(d\alpha)$ for some measure $m$, eventually a probability measure. In this paper an approach based on L\'evy mixing is proposed. ... More

Motifs et adjointsJun 28 2015Nov 23 2015We show in many cases the existence of adjoints to extension of scalars on categories of motivic nature, in the framework of field extensions. This is to be contrasted with the more classical situation where one deals with a finite type morphism of schemes. ... More

Approximate Policy Iteration Schemes: A ComparisonMay 12 2014We consider the infinite-horizon discounted optimal control problem formalized by Markov Decision Processes. We focus on several approximate variations of the Policy Iteration algorithm: Approximate Policy Iteration, Conservative Policy Iteration (CPI), ... More

Operationalization of Basic Observables in MechanicsApr 10 2015Dec 03 2015This novel approach to the foundation of the physical theory begins with Hermann von Helmholtz fundamental analysis of basic measurements. We explain the mathematical formalism from the operationalization of basic observables. According to Leibniz resp. ... More

Uniform van Lambalgen's theorem fails for computable randomnessOct 02 2015We show that there exists a bitsequence that is not computably random for which its odd bits are computably random and its even bits are computably random relative to the odd bits. This implies that the uniform variant of van Lambalgen's theorem fails ... More

Bounded-degree factors of lacunary multivariate polynomialsDec 11 2014Jan 29 2016In this paper, we present a new method for computing bounded-degree factors of lacunary multivariate polynomials. In particular for polynomials over number fields, we give a new algorithm that takes as input a multivariate polynomial f in lacunary representation ... More

Computing low-degree factors of lacunary polynomials: a Newton-Puiseux approachJan 19 2014Jun 24 2014We present a new algorithm for the computation of the irreducible factors of degree at most $d$, with multiplicity, of multivariate lacunary polynomials over fields of characteristic zero. The algorithm reduces this computation to the computation of irreducible ... More

On the Abel-Radon transform of locally residual currentsFeb 22 2010First we recall the definition of locally residual currents and their basic properties. We prove in this first section a trace theorem, that we use later. Then we define the Abel-Radon transform of a current ${\cal R}(\alpha)$, on a projective variety ... More

Cubical informal type theory: the higher groupoid structureJun 22 2018Following a project of developing conventions and notations for informal type theory carried out in the homotopy type theory book for a framework built out of an augmentation of constructive type theory with axioms governing higher-dimensional constructions ... More

Singular integrals and Hardy type spaces for the inverse Gauss measureJan 26 2018Let $\gamma_{-1}$ be the absolutely continuous measure on $\mathbb{R}^n$ whose density is the reciprocal of a Gaussian and consider the natural weighted Laplacian $\mathcal{A}$ on $L^2(\gamma_{-1})$. In this paper, we prove boundedness and unboundedness ... More

Collapses, products and LC manifoldsNov 24 2009May 16 2010Durhuus and Jonsson (1995) introduced the class of "locally constructible" (LC) triangulated manifolds and showed that all the LC 2- and 3-manifolds are spheres. We show here that for each d>3 some LC d-manifolds are not spheres. We prove this result ... More

Propositional dynamic logic for searching games with errorsJan 28 2014We investigate some finitely-valued generalizations of propositional dynamic logic with tests. We start by introducing the (n+1)-valued Kripke models and a corresponding language based on a modal extension of {\L}ukasiewicz many-valued logic. We illustrate ... More

A family of $ω_1$ many topological types of locally finite treesApr 15 2016Two rooted locally finite trees are considered equivalent if both can be embedded into each other as topological minors by means of tree-order preserving mappings. By exploiting Nash-William's Theorem, Matthiesen provided a non-constructive proof of the ... More

The critical random barrier for the survival of branching random walk with absorptionNov 11 2009We study a branching random walk on $\r$ with an absorbing barrier. The position of the barrier depends on the generation. In each generation, only the individuals born below the barrier survive and reproduce. Given a reproduction law, Biggins et al. ... More

La théorie des invariants des formes quadratiques ternaires revisitéeMay 27 2008The simultaneous invariants of 2, 3, 4 and 5 ternary quadratic forms under the group $\SL(3, {\Bbb C})$ were given by several authors (P. Gordan, C. Ciamberlini, H.W. Turnbull, J.A Todd), utilizing the symbolic method. Using the Jordan algebra structure ... More

The Poisson boundary of triangular matrices in a number fieldDec 11 2006Sep 19 2008The aim of this note is to describe the Poisson boundary of the group of invertible triangular matrices with coefficients in a number field. It generalizes to any dimension and to any number field a result of Brofferio concerning the Poisson boundary ... More

Random walk on a building of type $\tilde{A}_r$ and Brownian motion of the Weyl chamberNov 17 2006May 25 2009In this paper we study a random walk on an affine building of type $\tilde{A}_r$, whose radial part, when suitably normalized, converges to the Brownian motion of the Weyl chamber. This gives a new discrete approximation of this process, alternative to ... More

Tauberian theorems for general iterations of operators: applications to zero-sum stochastic gamesSep 07 2016This paper proves several Tauberian theorems for general iterations of operators, and provides two applications to zero-sum stochastic games where the total payoff is a weighted sum of the stage payoffs. The first application is to provide conditions ... More

1/f noise in grapheneSep 13 2013We present a novel and comprehensive model of 1/f noise in nanoscale graphene devices that accounts for the unusual and so far unexplained experimental characteristics. We find that the noise power spectral density versus carrier concentration of single-layer ... More

A finite set of local moves for Kirby calculusFeb 07 2011Aug 21 2012We exhibit a finite set of local moves that connect any two surgery presentations of the same 3-manifold via framed links in the three-sphere. The moves are handle-slides and blow-downs/ups of a particular simple kind.

Four-manifolds with shadow-complexity zeroSep 01 2009We prove that a closed 4-manifold has shadow-complexity zero if and only if it is a kind of 4-dimensional graph manifold, which decomposes into some particular blocks along embedded copies of S^2 x S^1, plus some complex projective spaces. We deduce a ... More

Superrigidity In Infinite Dimension And Finite Rank Via Harmonic MapsJun 09 2012We prove geometric superrigidity for actions of cocompact lattices in semisimple Lie groups of higher rank on infinite dimensional Riemannian manifolds of nonpositive curvature and finite telescopic dimension.

Foncteurs de Mackey à réciprocitéOct 29 2012This text was written 20 years ago, inspired by M. Somekawa's paper on K-groups attached to semi-abelian varieties (K-Theory 4 (1990), 105--119) and before Voevodsky's theory of presheaves with transfers. The reason why it only had a limited circulation ... More

Comment on "Space-Time Crystals of Trapped Ions": And Yet it Moves Not !Nov 20 2012A Comment on "Space-Time Crystals of Trapped ions", by Tongcang Li et al. (PRL 109, 163001 (2012); arXiv:1206.4772

Berry phase, topology, and diabolicity in quantum nano-magnetsNov 18 2005A topological theory of the diabolical points (degeneracies) of quantum magnets is presented. Diabolical points are characterized by their diabolicity index, for which topological sum rules are derived. The paradox of the the missing diabolical points ... More

Exchange interaction parameters and adiabatic spin-wave spectra of ferromagnets: A "renormalized magnetic force theorem"Jul 24 2002Aug 31 2004The ``magnetic force theorem'' is frequently used to compute exchange interaction parameters and adiabatic spin-wave spectra of ferromagnets. The interest of this approach is that it allows to obtain these results from a non-self-consistent calculation ... More

Should one compute the Temporal Difference fix point or minimize the Bellman Residual? The unified oblique projection viewNov 19 2010We investigate projection methods, for evaluating a linear approximation of the value function of a policy in a Markov Decision Process context. We consider two popular approaches, the one-step Temporal Difference fix-point computation (TD(0)) and the ... More

Fly-automata for checking MSO 2 graph propertiesNov 27 2015Dec 22 2015A more descriptive but too long title would be : Constructing fly-automata to check properties of graphs of bounded tree-width expressed by monadic second-order formulas written with edge quantifications. Such properties are called MSO2 in short. Fly-automata ... More

Superradiance: Classical, Relativistic and Quantum AspectsApr 13 2014Jul 12 2014Several physical systems can be treated as a scattering process, and, for these processes, a natural observed quantity arises: the ratio between the reflected and incident intensities, known as the reflection coefficient. This dissertation is concerned ... More

Analysis of a malaria model with mosquito host choice and bed-net controlNov 13 2013A malaria model is formulated which includes the enhanced attractiveness of infectious humans to mosquitoes, as result of host manipulation by malaria parasite, and the human behavior, represented by insecticide-treated bed nets usage. The occurrence ... More

Symmetrization for fractional Neumann problemsJan 27 2016Sep 01 2016In this paper we complement the program concerning the application of symmetrization methods to nonlocal PDEs by providing new estimates, in the sense of mass concentration comparison, for solutions to linear fractional elliptic and parabolic PDEs with ... More

Teaching an Old Elephant New TricksSep 09 2009In recent years, column stores (or C-stores for short) have emerged as a novel approach to deal with read-mostly data warehousing applications. Experimental evidence suggests that, for certain types of queries, the new features of C-stores result in orders ... More

Another Co*cryption MethodJul 21 2008We consider the enciphering of a data stream while being compressed by a LZ algorithm. This has to be compared to the classical encryption after compression methods used in security protocols. Actually, most cryptanalysis techniques exploit patterns found ... More

The 1-loop vacuum polarization for a graphene-like medium in an external magnetic field; corrections to the Coulomb potentialSep 06 2016I calculate the 1-loop vacuum polarization $\Pi_{\mu\nu}(k,B,a)$ for a photon of momentum $k=(\hat k,k_3)$ interacting with the electrons of a thin medium of thickness $2a$ simulating graphene, in the presence of a constant and uniform external magnetic ... More

P-adic lattices are not Kähler groupsOct 22 2017Jan 18 2019In this note we show that any lattice in a simple p-adic Lie group is not the fundamental group of a compact Ka\"hler manifold, as well as some variants of this result.

Old and new approaches to the Sorites paradoxApr 03 2017The Sorites paradox is the name of a class of paradoxes that arise when vague predicates are considered. Vague predicates lack sharp boundaries in extension and is therefore not clear exactly when such predicates apply. Several approaches to this class ... More

Dirac physical measures for generic diffeomorphismsSep 13 2016We prove that, for a $C^1$ generic diffeomorphism, the only Dirac physical measures with dense statistical basin are those supported on sinks.

Persuading part of an audienceMar 01 2019I propose a cheap-talk model in which the sender can use private messages and only cares about persuading a subset of her audience. For example, a candidate only needs to persuade a majority of the electorate in order to win an election. I find that senders ... More

Transition to turbulence in shear flowsJan 28 2018Pipe flow and many other shear flows show a transition to turbulence at flow rates for which the laminar profile is stable against infinitesimal perturbations. In this brief review the recent progress in the understanding of this transition will be summarized, ... More

Endpoint results for the Riesz transform of the Ornstein-Uhlenbeck operatorJan 22 2018In this paper we introduce a new atomic Hardy space $X^1(\gamma)$ adapted to the Gauss measure $\gamma$, and prove the boundedness of the first order Riesz transform associated with the Ornstein-Uhlenbeck operator from $X^1(\gamma)$ to $L^1(\gamma)$. ... More

A criterion for the differential flatness of a nonlinear control systemNov 14 2017Let's consider a control system described by the implicit equation $F(x,\dot x) = 0$. If this system is differentially flat, then the following criterion is satisfied : For some integer $r$, there exists a function $\varphi(y_0, y_1, ..,y_r)$ satisfying ... More