Results for "Alexandre Bernardino"

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Beyond the Self: Using Grounded Affordances to Interpret and Describe Others' ActionsFeb 26 2019We propose a developmental approach that allows a robot to interpret and describe the actions of human agents by reusing previous experience. The robot first learns the association between words and object affordances by manipulating the objects in its ... More
Unscented Bayesian Optimization for Safe Robot GraspingMar 07 2016We address the robot grasp optimization problem of unknown objects considering uncertainty in the input space. Grasping unknown objects can be achieved by using a trial and error exploration strategy. Bayesian optimization is a sample efficient optimization ... More
Interactive Robot Learning of Gestures, Language and AffordancesNov 24 2017A growing field in robotics and Artificial Intelligence (AI) research is human-robot collaboration, whose target is to enable effective teamwork between humans and robots. However, in many situations human teams are still superior to human-robot teams, ... More
Weighted Multisource TradaboostMar 26 2019In this paper we propose an improved method for transfer learning that takes into account the balance between target and source data. This method builds on the state-of-the-art Multisource Tradaboost, but weighs the importance of each datapoint taking ... More
Language Bootstrapping: Learning Word Meanings From Perception-Action AssociationNov 27 2017We address the problem of bootstrapping language acquisition for an artificial system similarly to what is observed in experiments with human infants. Our method works by associating meanings to words in manipulation tasks, as a robot interacts with objects ... More
Recurrent Instance SegmentationNov 25 2015Oct 24 2016Instance segmentation is the problem of detecting and delineating each distinct object of interest appearing in an image. Current instance segmentation approaches consist of ensembles of modules that are trained independently of each other, thus missing ... More
An Inequality with Applications to Structured Sparsity and Multitask Dictionary LearningFeb 08 2014Jun 07 2014From concentration inequalities for the suprema of Gaussian or Rademacher processes an inequality is derived. It is applied to sharpen existing and to derive novel bounds on the empirical Rademacher complexities of unit balls in various norms appearing ... More
Applying Domain Randomization to Synthetic Data for Object Category DetectionJul 16 2018Recent advances in deep learning-based object detection techniques have revolutionized their applicability in several fields. However, since these methods rely on unwieldy and large amounts of data, a common practice is to download models pre-trained ... More
Learning at the Ends: From Hand to Tool Affordances in Humanoid RobotsApr 09 2018One of the open challenges in designing robots that operate successfully in the unpredictable human environment is how to make them able to predict what actions they can perform on objects, and what their effects will be, i.e., the ability to perceive ... More
Cleaning tasks knowledge transfer between heterogeneous robots: a deep learning approachMar 13 2019Nowadays, autonomous service robots are becoming an important topic in robotic research. Differently from typical industrial scenarios, with highly controlled environments, service robots must show an additional robustness to task perturbations and changes ... More
Fast calculation of entropy with Zhang's estimatorJul 26 2017Entropy is a fundamental property of a repertoire. Here, we present an efficient algorithm to estimate the entropy of types with the help of Zhang's estimator. The algorithm takes advantage of the fact that the number of different frequencies in a text ... More
Superconducting qubitsMay 01 2008From a physicist's standpoint, the most interesting part of quantum computing research may well be the possibility to probe the boundary between the quantum and the classical worlds. The more macroscopic are the structures involved, the better. So far, ... More
A numerical approach to harmonic non-commutative spectral field theoryNov 13 2011Mar 26 2012We present a first numerical investigation of a non-commutative gauge theory defined via the spectral action for Moyal space with harmonic propagation. This action is approximated by finite matrices. Using Monte Carlo simulation we study various quantities ... More
Wetting of cholesteric liquid crystalsJul 16 2015We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted the wetting properties are similar to ... More
Noncommutative Field Theory: Numerical Analysis with the Fuzzy DiscJul 20 2012Jul 28 2012The fuzzy disc is a discretization of the algebra of functions on the two dimensional disc using finite matrices which preserves the action of the rotation group. We define a $\varphi^4$ scalar field theory on it and analyze numerically for three different ... More
Finite orbits of the braid group action on sets of reflectionsSep 14 2004Jun 01 2006The finite orbits of the braid group action on Stokes matrices are studied and are shown to be the orbits on ordered sets of reflections, generating finite groups. All invariants of a reflection arrangement are determined. Determination of the orbits ... More
Analytic twists of modular formsAug 29 2016We investigate non-correlation of Fourier coefficients of Maass forms against a class of real oscillatory functions, in analogy to known results with Frobenius trace functions. We also establish an equidistribution result for twisted horocycles as a consequence ... More
Is there switching without suspended horseshoes?Nov 27 2015In general, infinite switching behaviour near networks is associated with the existence of suspended horseshoes. Trajectories that realize switching lie within these transitive sets. In this note, revisiting the equivariant Shilnikov scenario, we describe ... More
On the limiting absorption principle for Schröedinger HamiltoniansOct 13 2015May 03 2016We prove the limiting absorption principle and discuss the continuity properties of the boundary values of the resolvent for a class of form bounded perturbations of the Euclidean Laplacian $\Delta$ that covers both short and long range potentials with ... More
Spatio-temporal averaging for a class of hybrid systems. Application to conductance-based neuron modelsMar 07 2014Nov 25 2015We obtain a limit theorem endowed with quantitative estimates for a general class of infinite dimensional hybrid processes with intrinsically two different time scales and including a population. As an application, we consider a large class of conductance-based ... More
Convergence properties of the Gronwall area formula for quadratic Julia setsMay 08 2014Jul 23 2015Using parabolic enrichment, it is shown that Gronwall area formula for the filled Julia set along the boundary of the main cardioid of the Mandelbrot set cannot be well approximated by replacing it by a finite sum. A revised version of this article will ... More
A Lyapunov function for Glauber dynamics on lattice triangulationsApr 29 2015We study random triangulations of the integer points $[0,n]^2 \cap\mathbb{Z}^2$, where each triangulation $\sigma$ has probability measure $\lambda^{|\sigma|}$ with $|\sigma|$ denoting the sum of the length of the edges in $\sigma$. Such triangulations ... More
Cepheids at high angular resolution: circumstellar envelope and pulsationDec 23 2011In 2005, interferometric observations with VLTI/VINCI and CHARA/FLUOR revealed the existence of a circumstellar envelope (CSE) around some Cepheids. This surrounding material is particularly interesting for two reasons: it could have an impact on the ... More
Building Generalized Neo-Riemannian Groups of Musical Transformations as ExtensionsNov 18 2011Aug 12 2012Chords in musical harmony can be viewed as objects having shapes (major/minor/etc.) attached to base sets (pitch class sets). The base set and the shape set are usually given the structure of a group, more particularly a cyclic group. In a more general ... More
From N=1 to N=2 supersymmetries in 2+1 dimensionsJan 07 2003Apr 10 2003Starting from N=1 scalar and vector supermultiplets in 2+1 dimensions, we construct superfields which constitute Lagrangians invariant under N=2 supersymmetries. We first recover the N=2 supersymmetric Abelian-Higgs model and then the N=2 pure super Yang-Mills ... More
Vacuum polarization in thermal QED with an external magnetic fieldSep 26 2000Jan 15 2001The one-loop vacuum polarization tensor is computed in QED with an external constant, homogeneous magnetic field at finite temperature. The Schwinger proper-time formalism is used and the computations are done in Euclidian space. The well-known results ... More
Weak Gravitational Lensing by Large-Scale StructureJul 10 2003Weak gravitational lensing provides a unique method to map directly the distribution of dark matter in the universe and to measure cosmological parameters. This cosmic-shear technique is based on the measurement of the weak distortions that lensing induces ... More
Evolutionary stellar population synthesis at 2A spectral resolutionJan 14 1999We present an evolutionary stellar population synthesis model which predicts SED's for simple stellar populations, SSP's, at ~2A resolution in the visible. The input database is composed of ~550 stars, selected from the spectral library of Jones. This ... More
Exact 3D solution for static and damped harmonic response of simply supported general laminatesJul 19 2013Jul 01 2014The state-space method is adapted to obtain three dimensional exact solutions for the static and damped dynamic behaviors of simply supported general laminates. The state-space method is written in a general form that permits to handle both cross-ply ... More
Transverse shear warping functions for anisotropic multilayered platesNov 05 2012In this work, transverse shear warping functions for an equivalent single layer plate model are formulated from a variational approach. The part of the strain energy which involves the shear phenomenon is expressed in function of the warping functions ... More
On the Exponentiation of Interval MatricesAug 27 2009The numerical computation of the exponentiation of a real matrix has been intensively studied. The main objective of a good numerical method is to deal with round-off errors and computational cost. The situation is more complicated when dealing with interval ... More
Induced representations of infinite-dimensional groupsJun 30 2012The induced representation ${\rm Ind}_H^GS$ of a locally compact group $G$ is the unitary representation of the group $G$ associated with unitary representation $S:H\rightarrow U(V)$ of a subgroup $H$ of the group $G$. Our aim is to develop the concept ... More
A Markov-type inequality for arbitrary plane continuaJun 29 2006A version of Markov's estimate for the derivative of a polynomial is proved with the interval [-1,1] replaced by an arbitrary continuum in the complex plane.
On the analogy between real reductive groups and Cartan motion groups. III: A proof of the Connes-Kasparov isomorphismFeb 29 2016Aug 29 2018Alain Connes and Nigel Higson pointed out in the 1990s that the Connes-Kasparov "conjecture"' for the K-theory of reduced groupe $C^\ast$-algebras seemed, in the case of reductive Lie groups, to be a cohomological echo of a conjecture of George Mackey ... More
On the hyperbolic metric of the complement of a rectangular latticeOct 12 2011Oct 14 2011The density of the hyperbolic metric on the complement of a rectangular lattice is investigated. The question is related to conformal mapping of symmetric circular quadrilaterals with all zero angles.
Exceptional values in holomorphic families of entire functionsMar 31 2005We study Picard's exceptional values of holomorphic one-parametric families of entire functions. Our first result shows that the set of parameter values for which zero is a Picard value can be an arbitrary closed set of zero logarithmic capacity. This ... More
Fast loops on semi-weighted homogeneous hypersurface singularitiesMar 14 2010Mar 22 2010We show the existence of ($1+\frac{w_2}{w_3}$)-fast loops on semi-weighted homogeneous hypersurface singularities with weights $w_1\geq w_2>w_3$. In particular we show that semi-weighted homogeneous hypersurface singularities have metrical conical structure ... More
Proceedings of the 12th International Workshop on Logic Programming EnvironmentsJul 12 2002The twelfth Workshop on Logic Programming Environments, WLPE 2002, is one in a series of international workshops held in the topic area. The workshops facilitate the exchange ideas and results among researchers and system developers on all aspects of ... More
A version of Fabry's theorem for power series with regularly varying coefficientsOct 31 2007Apr 22 2008For real power series whose non-zero coefficients satisfy $|a_m|^{1/m}\to~1$ we prove a stronger version of Fabry theorem relating the frequency of sign changes in the coefficients and analytic continuation of the sum of the power series.
A non-commutative algorithm for multiplying (7 $\times$ 7) matrices using 250 multiplicationsDec 21 2017We present a non-commutative algorithm for multiplying (7x7) matrices using 250 multiplications and a non-commutative algorithm for multiplying (9x9) matrices using 520 multiplications. These algorithms are obtained using the same divide-and-conquer technique. ... More
Lorenz curves interpretations of the Bruss-Duerinckx theorem for resource dependent branching processesAug 03 2017The Bruss and Duerinckx theorem for resource dependent branching processes states that the survival of any society form is nested in an envelope formed by two extreme policies. The objective of this paper is to give a novel interpretation of this theorem ... More
Artin Groups and Iwahori-Hecke algebras over finite fieldsAug 10 2018In this doctoral thesis, we will determine the image of Artin groups associated to all finite irreducible Coxeter groups inside their associated finite Iwahori-Hecke algebra. This was done in type $A$ by Brunat, Magaard and Marin. The Zariski closure ... More
Lagrangian cobordism groups of higher genus surfacesJan 17 2019We study Lagrangian cobordism groups of oriented surfaces of genus greater than two. We compute the immersed oriented Lagrangian cobordism group of these surfaces. We show that a variant of this group, with relations given by unobstructed immersed Lagrangian ... More
Laderman matrix multiplication algorithm can be constructed using Strassen algorithm and related tensor's isotropiesMar 24 2017May 10 2017In 1969, V. Strassen improves the classical~2x2 matrix multiplication algorithm. The current upper bound for 3x3 matrix multiplication was reached by J.B. Laderman in 1976. This note presents a geometric relationship between Strassen and Laderman algorithms. ... More
The squeezed matter bispectrum covariance with responsesJan 04 2019We present a calculation of the angle-averaged squeezed matter bispectrum covariance ${\rm Cov}\left(B_{m}(k_1, k_1', s_1), B_{m}(k_2, k_2', s_2)\right)$, $s_i \ll k_i,k_i'$ ($i=1,2$), that uses matter power spectrum responses to describe the coupling ... More
Relative homological linkingNov 27 2003Jan 29 2008Using Morse theory and a new relative homological linking of pairs, we prove a ``homological linking principle'', thereby generalizing many well known results in critical point theory.
Some singular sample path properties of a multiparameter fractional Brownian motionOct 16 2014May 23 2016We prove a Chung-type law of the iterated logarithm for a multiparameter extension of the fractional Brownian motion which is not increment stationary. This multiparameter fractional Brownian motion behaves very differently at the origin and away from ... More
Cartan-Weyl Basis for Yangian Double $DY(sl_3)$Apr 13 1997We give a new realization of $Y(sl_3)$ via Cartan-Weyl elements. An algebraic description of Yangian Double $DY(sl_3)$, explicit comultiplication formulas and universal R-matrix are obtained in these terms.
Dynamical mass generation in Lorentz-violating QEDSep 29 2010Mar 08 2013A Lorentz violating modification of massless QED is proposed, with higher order space derivatives for the photon field. The fermion dynamical mass generation is studied with the Schwinger-Dyson approach, and it is found that the resulting mass is many ... More
A new non-perturbative time-dependent string configurationAug 10 2007A time-dependent bosonic string configuration is discussed, in graviton and dilaton backgrounds, leading to Weyl-symmetry beta-functions which are homogeneous in X^0, to any order in alpha'. As a consequence, a string reparametrization can always be implemented, ... More
QED in external fields, a functional point of viewJan 17 2001Jun 25 2001A functional partial differential equation is set for the proper graphs generating functional of QED in external electromagnetic fields. This equation leads to the evolution of the proper graphs with the external field amplitude and the external field ... More
A Toda lattice in dimension 2 and Nevanlinna theoryNov 07 2004It is shown how to study the 2-D Toda system for SU(n+1) using Nevanlinna theory of meromorphic functions and holomorphic curves. The results generalize recent results of Jost - Wang and Chen - Li.
Criteria of irreducibility of the Koopman representations for the group ${\rm GL}_0(2\infty,{\mathbb R})$Oct 15 2016Our aim is to find the irreducibility criteria for the Koopman representation, when the group acts on some space with a measure (Conjecture 1.5). Some general necessary conditions of the irreducibilty of this representation are established. In the particular ... More
Averaging for some simple constrained Markov processesJun 24 2016Aug 30 2016In this paper, a class of piecewise deterministic Markov processes with underlying fast dynamic is studied. Using a "penalty method" , an averaging result is obtained when the underlying dynamic is infinitely accelerated. The features of the averaged ... More
A Mackey-Analogy based Proof of the Connes-Kasparov Isomorphism for Real Reductive GroupsFeb 29 2016We give a new representation-theory based proof of the Connes-Kasparov conjecture for the K-theory of reduced C*-algebras of real reductive Lie groups. Our main tool is a natural correspondence between the tempered representation theory of such a group ... More
Invariant Gaussian Fields on Homogeneous Spaces : Explicit Constructions and Geometric Measure of the Zero-setFeb 08 2016This paper is concerned with the properties of Gaussian random fields defined on a riemannian homogeneous space, under the assumption that the probability distribution be invariant under the isometry group of the space. We first indicate, building on ... More
Swiss Cheese type operads and models for relative loop spacesNov 18 2015Aug 05 2016We construct a (coloured) operad RL in the category of sets that may be thought of as a combinatorial model for the Swiss Cheese operad. By adapting Batanin-Berger's condensation process we obtain a topological (resp. chain) operad weakly equivalent to ... More
How tempered representations of a semisimple Lie group contract to its Cartan motion groupOct 09 2015George W. Mackey suggested in 1975 that there should be analogies between the irreducible unitary representations of a noncompact semisimple Lie group $G$ and those of its Cartan motion group - the semidirect product $G_0$ of a maximal compact subgroup ... More
Modeling Dense Urban Wireless Networks with 3D Stochastic GeometrySep 10 2015Feb 05 2016Over the past decade, many works on the modeling of wireless networks using stochastic geometry have been proposed. Results about probability of coverage, throughput or mean interference, have been provided for a wide variety of networks (cellular, ad-hoc, ... More
Study of Charmonium Production in Asymmetric Nuclear Collisions by the PHENIX Experiment at RHICSep 11 2015The measurement of quarkonia production in relativistic heavy ion collisions provides a powerful tool for studying the properties of the hot and dense matter created in these collisions. To be really useful, however, such measurements must cover a wide ... More
Lorentz-symmetry violation and dynamical flavour oscillationsDec 15 2013We show how a mass mixing matrix can be generated dynamically, for two massless fermion flavours coupled to a Lorentz invariance violating (LIV) gauge field. The LIV features play the role of a regulator for the gap equations, and the non-analytic dependence ... More
Population viewpoint on Hawkes processesApr 24 2015This paper focuses on a class of linear Hawkes processes with general immigrants. These are counting processes with shot noise intensity, including self-excited and externally excited patterns. For such processes, we introduce the concept of age pyramid ... More
The Ismagilov conjecture over a finite field ${\mathbb F}_p$Dec 04 2016We construct the so-called quasiregular representations of the group of infinite upper triangular matrices with coefficients in a finite field and give the criteria of theirs irreducibility in terms of the initial measure. These representations are particular ... More
Rich subcontextsJan 12 2017For a finite binary relation, we show a local operation which does not decrease its number of (Galois-)closed sets and eventually increases its (Vapnik-Chervonenkis)-dimension. Specifically, we show that there always exist a pair of elements, one belonging ... More
Special Symplectic Subgroup over Integers Arising as a Factor of The Braid GroupFeb 13 2004Oct 20 2004There is a natural action of the braid group on the symmetric matrices with units on the diagonal, appearing in various fields as Singularity Theory, Frobenius Manifolds or Isomonodromic deformations of certain classes of linear differential systems. ... More
Geometric Median ShapesOct 29 2018Nov 07 2018We present an algorithm to compute the geometric median of shapes which is based on the extension of median to high dimensions. The median finding problem is formulated as an optimization over distances and it is solved directly using the watershed method ... More
On inverse problems in electromagnetic field in classical mechanics at fixed energyJan 04 2007In this paper, we consider inverse scattering and inverse boundary value problems at sufficiently large and fixed energy for the multidimensional relativistic and nonrelativistic Newton equations in a static external electromagnetic field $(V,B)$, $V\in ... More
Segre varieties, CR geometry and Lie symmetries of second order PDE systemsFeb 21 2000We show that biholomorphic automorphisms of a real analytic CR manifold can be considered as (pointwise) Lie symmetries of a holomorphic second order PDE system defining its Segre family. This allows to use general methods of the geometric PDE theory ... More
Mathematics discovered, invented, and inheritedSep 12 2013Sep 22 2013The classical platonist/formalist dilemma in philosophy of mathematics can be expressed in lay terms as a deceptively naive question: is new mathematics discovered or invented? Using an example from my own mathematical life, I argue that there is also ... More
Ahlfors circle maps and total reality: from Riemann to RohlinNov 15 2012Apr 16 2013This is a prejudiced survey on the Ahlfors (extremal) function and the weaker {\it circle maps} (Garabedian-Schiffer's translation of "Kreisabbildung"), i.e. those (branched) maps effecting the conformal representation upon the disc of a {\it compact ... More
Multichannel algorithm based on generalized positional numeration systemOct 04 2007This report is devoted to introduction in multichannel algorithm based on generalized numeration notations (GPN). The internal, external and mixed account are entered. The concept of the GPN and its classification as decomposition of an integer on composed ... More
Complexes of Groups and BoundariesJan 30 2012Given a complex of groups over a finite simplicial complex in the sense of Haefliger, we give conditions under which it is possible to build an EZ-structure in the sense of Farrell-Lafont for its fundamental group out of such structures for its local ... More
On the cubical geometry of Higman's groupJun 09 2015Jun 27 2016We investigate the cocompact action of Higman's group on a CAT(0) square complex associated to its standard presentation. We show that this action is in a sense intrinsic, which allows for the use of geometric techniques to study the endomorphisms of ... More
Densities in Fabry's theoremSep 14 2007Mar 02 2009Fabry's theorem on the singularities of power series is improved: the maximum density in the assumptions of this theorem is replaced by an interior density of Beurling--Malliavin type.
A separable manifold failing to have the homotopy type of a CW-complexSep 23 2006We show that the Pr\"ufer surface, which is a separable non-metrizable 2-manifold, has not the homotopy type of a CW-complex. This will follow easily from J. H. C. Whitehead's result: if one has a good approximation of an arbitrary space by a CW-complex, ... More
On the Wong-Rosay theoremApr 28 2019We prove a Wong-Rosay type theorem for a domain with a piecewise smooth generic strictly pseudoconvex boundary point.
European Court of Human Right Open Data projectOct 07 2018Feb 04 2019This paper presents thirteen datasets for binary, multiclass and multilabel classification based on the European Court of Human Rights judgments since its creation. The interest of such datasets is explained through the prism of the researcher, the data ... More
Representations of matroids and free resolutions for multigraded modulesSep 30 2004Oct 07 2004Let K be a field, let R=K[x_1,..., x_m] be a polynomial ring with the standard Z^m-grading (multigrading), let L be a Noetherian multigraded R-module, and let F: E --> G be a finite free multigraded presentation of L over R. Given a choice S of a multihomogeneous ... More
Mean Curvature Motion of Graphs with Constant Contact Angle at a Free BoundaryDec 08 2008We consider the motion by mean curvature of an $n$-dimensional graph over a time-dependent domain in $\mathbb{R}^n$, intersecting $\mathbb{R}^n$ at a constant angle. In the general case, we prove local existence for the corresponding quasilinear parabolic ... More
On inverse scattering for the multidimensional relativistic Newton equation at high energiesFeb 16 2005Jul 10 2006Consider the Newton equation in the relativistic case (that is the Newton-Einstein equation) $$\eqalign{\dot p = F(x),& F(x)=-\nabla V(x),\cr p={\dot x \over \sqrt{1-{|\dot x|^2 \over c^2}}},& \dot p={dp\over dt}, \dot x={dx\over dt}, x\in C^1(\R,\R^d),}\eqno{(*)}$$ ... More
Meromorphic functions with three singular valuesSep 01 2003Feb 27 2004The minimal possible rate of growth of a meromorphic function with three critical values is found.
Entire functions, PT-symmetry and Voros's quantization schemeOct 08 2015In this paper, A. Avila's theorem on convergence of the exact quantization scheme of A. Voros is related to the reality proofs of eigenvalues of certain PT-symmetric boundary value problems. As a result, a special case of a conjecture of C. Bender, S. ... More
On metrics of constant positive curvature with four conic singularities on the sphereMay 07 2019We show that for given four points on the sphere and prescribed angles at these points, which are not multiples of $2\pi$, the number of metrics of curvature 1 having conic singularities with these angles at these points is finite.
On the analogy between real reductive groups and Cartan motion groups. I: The Mackey-Higson bijectionOct 09 2015Aug 28 2018George Mackey suggested in 1975 that there should be analogies between the irreducible unitary representations of a noncompact reductive Lie group $G$ and those of its Cartan motion group $G_0$ $-$ the semidirect product of a maximal compact subgroup ... More
Colored Kac-Moody Algebras, Part IDec 30 2014Sep 28 2015We introduce a parametrization of formal deformations of Verma modules of $\mathfrak{sl}_2$. A point in the moduli space is called a colouring. We prove that for each colouring $\psi$ satisfying a regularity condition, there is a formal deformation $U_h(\psi)$ ... More
Dynamic Code Coverage with Progressive Detail LevelsJun 19 2013Nowadays, locating software components responsible for observed failures is one of the most expensive and error-prone tasks in the software development process. To improve the debugging process efficiency, some effort was already made to automatically ... More
Generic smooth representationsMar 06 2018Let $F$ be a finite extension of $\mathbb{Q}_p$. Here we give a necessary and sufficient condition for an irreducible smooth representation of $GL_n(F)$ to be generic.
Two-scale semi-lagrangian simulation of a charged particle beam in a periodic focusing channelDec 19 2008This paper is devoted to numerical simulation of a charged particle beam submitted to a strong oscillating electric field. For that, we consider a two-scale numerical approach as follows: we first recall the two-scale model which is obtained by using ... More
The Lawrence-Krammer representation is a quantization of the symmetric square of the Burau representationSep 21 2016Oct 18 2017We show that the Lawrence--Krammer representation can be obtained as the quantization of the symmetric square of the Burau representation. This connection allows us to construct new representations of braid groups
ShaResNet: reducing residual network parameter number by sharing weightsFeb 28 2017Mar 06 2017Deep Residual Networks have reached the state of the art in many image processing tasks such image classification. However, the cost for a gain in accuracy in terms of depth and memory is prohibitive as it requires a higher number of residual blocks, ... More
Acylindrical actions on CAT(0) square complexesSep 10 2015For group actions on hyperbolic CAT(0) square complexes, we show that the acylindricity of the action is equivalent to a weaker form of acylindricity phrased purely in terms of stabilisers of points, which has the advantage of being much more tractable ... More
Exponential speed of uniform convergence of the cell density toward equilibrium for subcritical mass in a Patlak-Keller-Segel modelMay 31 2014This paper is concerned with a chemotaxis aggregation model for cells, more precisely with a parabolic-elliptic semilinear Patlak-Keller-Segel system in a ball of $\mathbb{R}^N$ for $N\geq 2$. For $N=2$, this system is well known for its critical mass ... More
Using Monoidal Categories in the Transformational Study of Musical Time-Spans and RhythmsMay 30 2013Aug 06 2013Transformational musical theory has so far mainly focused on the study of groups acting on musical chords, one of the most famous example being the action of the dihedral group D24 on the set of major and minor chords. Comparatively less work has been ... More
Spontaneous symmetry breaking and linear effective potentialsMay 05 2012The convexity of a scalar effective potential is a well known property, and, in the situation of spontaneous symmetry breaking, leads to the so-called Maxwell construction, characterised by a flat effective potential between the minima of the bare potential. ... More
Non critical superstring configuration and Minkowski space time in four dimensionsMar 15 2006Feb 21 2007We extend the non-perturbative time-dependent bosonic string action of [3] to a N=1 supersymmetric world sheet action with graviton background, and assume a superpotential, function of the time super coordinate.
Concepts of Renormalization in PhysicsAug 24 2005A non technical introduction to the concept of renormalization is given, with an emphasis on the energy scale dependence in the description of a physical system. We first describe the idea of scale dependence in the study of a ferromagnetic phase transition, ... More
Space-time percolation and detection by mobile nodesAug 31 2011Sep 09 2015Consider the model where nodes are initially distributed as a Poisson point process with intensity $\lambda$ over $\mathbb{R}^d$ and are moving in continuous time according to independent Brownian motions. We assume that nodes are capable of detecting ... More
A counterexample to the Arakelyan ConjectureJul 01 1992A ``self--similar'' example is constructed that shows that a conjecture of N. U. Arakelyan on the order of decrease of deficiencies of an entire function of finite order is not true.
Multifidelity variance reduction for pick-freeze Sobol index estimationMar 25 2013Many mathematical models involve input parameters, which are not precisely known. Global sensitivity analysis aims to identify the parameters whose uncertainty has the largest impact on the variability of a quantity of interest (output of the model). ... More
Groupes Quantiques d'Interpolation de Langlands de Rang 1Jul 11 2011Interpolating Langlands Quantum Groups of Rank 1 -- We study a certain family, parameterized by an positive integer g, of double deformations of the envelopping algebra U(sl2), in the spirit of arXiv:0809.4453. We prove that each of these double deformations ... More