Results for "André Hofmeister Serra"
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On the source of viscosity in cool binary accretion disksJan 18 1999We suggest that the low viscosity in close binary accretion disks during quiescence is due to magnetic fields from the companion star. In very late evolutionary phase the companion stars become brown dwarfs and have cooled down to such low a temperature ... More On the ultimate fate of AM Her starsMay 06 1999We suggest, that the magnetic field of the white dwarf in AM Her systems loses coupling to the secondary star when the latter becomes non-magnetic at the transition from a late main sequence star to a cool degenerate brown dwarf. This leads to spin-up ... More A higgs-like dilaton: viability and implicationsDec 01 2013We re-examine the feasibility of the higgs-like particle discovered at the LHC being a dilaton: the Goldstone boson of spontaneous breaking of scale invariance. We review the expected phenomenological deviations from the SM higgs and compare with other ... More Beyond the Minimal Top Partner DecayJun 16 2015Jan 13 2016Light top partners are the prime sign of naturalness in composite Higgs models. We explore here the possibility of non-standard top partner phenomenology. We show that even in the simplest extension of the minimal composite Higgs model, featuring an extra ... More Riemann Hypothesis and Random Walks: the Zeta caseJan 05 2016Feb 05 2016In previous work it was shown that if certain series based on sums over primes of non-principal Dirichlet characters have a conjectured random walk behavior, then the Euler product formula for its $L$-function is valid to the right of the critical line ... More On large gaps between zeros of $L$-functions from branchesApr 19 2017May 26 2017It is commonly believed that the normalized gaps between consecutive ordinates $t_n$ of the zeros of the Riemann zeta function on the critical line can be arbitrarily large. In particular, drawing on analogies with random matrix theory, it has been conjectured ... More Quadric bundles applied to non-maximal Higgs bundlesAug 01 2016We present a survey on the moduli spaces of rank 2 quadric bundles over a compact Riemann surface X. These are objects which generalise orthogonal bundles and which naturally occur through the study of the connected components of the moduli spaces of ... More The Froissart bound for inelastic cross-sectionsApr 23 2009Aug 14 2009We prove that while the total cross{}-section is bounded by $(\pi/m_\pi^2) \ln^2 s$, where $s$ is the square of the c.m. energy and $m_\pi$ the mass of the pion, the total inelastic cross{}-section is bounded by $(1/4)(\pi/m_\pi^2) \ln^2 s$, which is ... More Poincaré and log-Sobolev inequalities for mixturesDec 16 2018This work studies mixtures of probability measures on $\mathbb{R}^n$ and gives bounds on the Poincar\'e and the log-Sobolev constant of two-component mixtures provided that each component satisfies the functional inequality, and both components are close ... More Groupes de Galois motivques et périodesJun 12 2016In the mid sixties, A. Grothendieck envisioned a vast generalization of Galois theory to systems of polynomials in several variables, motivic Galois theory, and introduced tannakian categories on this occasion. In characteristic zero, various unconditional ... More The Herschel View of Star FormationSep 30 2013Recent studies of the nearest star-forming clouds of the Galaxy at submillimeter wavelengths with the Herschel Space Observatory have provided us with unprecedented images of the initial conditions and early phases of the star formation process. The Herschel ... More Local functional principal component analysisFeb 21 2007Covariance operators of random functions are crucial tools to study the way random elements concentrate over their support. The principal component analysis of a random function X is well-known from a theoretical viewpoint and extensively used in practical ... More Weak convergence in the functional autoregressive modelSep 12 2005The functional autoregressive model is a Markov model taylored for data of functional nature. It revealed fruitful when attempting to model samples of dependent random curves and has been widely studied along the past few years. This article aims at completing ... More Differential Hybrid GamesJul 17 2015Feb 24 2017This article introduces differential hybrid games, which combine differential games with hybrid games. In both kinds of games, two players interact with continuous dynamics. The difference is that hybrid games also provide all the features of hybrid systems ... More A sharpening of Li's criterion for the Riemann HypothesisApr 10 2004Apr 15 2004Exact and asymptotic formulae are displayed for the coefficients $\lambda_n$ used in Li's criterion for the Riemann Hypothesis. In particular, we argue that if (and only if) the Hypothesis is true, $\lambda_n \sim n(A \log n +B)$ for $n \to \infty$ (with ... More Viterbi Algorithm Generalized for n-Tape Best-Path SearchDec 07 2006We present a generalization of the Viterbi algorithm for identifying the path with minimal (resp. maximal) weight in a n-tape weighted finite-state machine (n-WFSM), that accepts a given n-tuple of input strings (s_1,... s_n). It also allows us to compile ... More Noncommutative polynomial mapsAug 01 2012Polynomial maps attached to polynomials of an Ore extension are naturally defi ned. In this setting we show the importance of pseudo-linear transformations and give some applications. In particular, factorizations of polynomials in an Ore extension over ... More Riemann Hypothesis and Random Walks: the Zeta caseJan 05 2016May 23 2017In previous work it was shown that if certain series based on sums over primes of non-principal Dirichlet characters have a conjectured random walk behavior, then the Euler product formula for its $L$-function is valid to the right of the critical line ... More Macroscopic limit of the Becker-Döring equation via gradient flowsJul 29 2016Feb 26 2018This work considers gradient structures for the Becker-D\"oring equation and its macroscopic limits. The result of Niethammer [17] is extended to prove the convergence not only for solutions of the Becker-D\"oring equation towards the Lifshitz-Slyozov-Wagner ... More On octahedraliy and Müntz spacesNov 05 2018We show that every M\"untz space can be written as a direct sum of Banach spaces X and Y , where Y is almost isometric to a subspace of c and X is finite dimensional. We apply this to show that no M\"untz space is locally octahedral or almost square. Dynamic Logics of Dynamical SystemsMay 22 2012We survey dynamic logics for specifying and verifying properties of dynamical systems, including hybrid systems, distributed hybrid systems, and stochastic hybrid systems. A dynamic logic is a first-order modal logic with a pair of parametrized modal ... More On the Kodaira-Spencer map of abelian schemesJun 12 2016Let $A$ be an abelian scheme over a smooth affine complex variety $S$, $\varOmega_A$ the $\sO_S$-module of $1$-forms of the first kind on $A$, $\sD_S\varOmega_A$ the $\sD_S$-module spanned by $\varOmega_A$ in the first algebraic De Rham cohomology module, ... More Interstellar filaments and star formationOct 03 2017Recent studies of the nearest star-forming clouds of the Galaxy at submillimeter wavelengths with the Herschel Space Observatory have provided us with unprecedented images of the initial conditions and early phases of the star formation process. The Herschel ... More Uniform sheaves and differential equationsJul 14 2012Real blow-ups and more refined "zooms" play a key role in the analysis of singularities of complex-analytic differential modules. They do not change the underlying topology, but the uniform structure. This suggests to revisit the cohomology theory of ... More Differential Game LogicAug 08 2014Jul 24 2015Differential game logic (dGL) is a logic for specifying and verifying properties of hybrid games, i.e. games that combine discrete, continuous, and adversarial dynamics. Unlike hybrid systems, hybrid games allow choices in the system dynamics to be resolved ... More Discretized Keiper/Li approach to the Riemann HypothesisMar 08 2017Jul 17 2017The Keiper--Li sequence $\{ \lambda _n \}$ is most sensitive to the Riemann Hypothesis asymptotically ($n \to \infty$), but highly elusive both analytically and numerically. We deform it to fully explicit sequences, simpler to analyze and to compute (up ... More A benchmark library for parametric timed model checkingDec 20 2018Verification of real-time systems involving hard timing constraints and concurrency is of utmost importance. Parametric timed model checking allows for formal verification in the presence of unknown timing constants or uncertainty (e.g. imprecision for ... More Early inflation based on an aboriginal black holeJul 01 2019It has been recently proposed that the interior of a black hole is vacuum energy, and this offers a possible explanation for the dark energy of the current observable universe. In this article we explore the idea that black holes are a source of vacuum ... More Formalizing Time4sys using parametric timed automataMay 23 2019Critical real-time systems must be verified to avoid the risk of dramatic consequences in case of failure. Thales developed an open formalism Time4sys to model real-time systems, with expressive features such as periodic or sporadic tasks, task dependencies, ... More An introduction to motivic zeta functions of motivesDec 19 2008It oftens occurs that Taylor coefficients of (dimensionally regularized) Feynman amplitudes $I$ with rational parameters, expanded at an integral dimension $D= D_0$, are not only periods (Belkale, Brosnan, Bogner, Weinzierl) but actually multiple zeta ... More Sharpenings of Li's criterion for the Riemann HypothesisJun 16 2005Jan 25 2006Exact and asymptotic formulae are displayed for the coefficients $\lambda_n$ used in Li's criterion for the Riemann Hypothesis. For $n \to \infty$ we obtain that if (and only if) the Hypothesis is true, $\lambda_n \sim n(A \log n +B)$ (with $A>0$ and ... More 3-Phase Evolution of a Coronal Hole, Part II: The Magnetic FieldJun 26 2018Jul 04 2019We investigate the magnetic characteristics of a persistent coronal hole (CH) extracted from EUV imagery using HMI filtergrams over the timerange February 2012-October 2012. The magnetic field, its distribution as well as the magnetic fine structure in ... More Cold gas and young stars in tidally-disturbed ellipticals at z=0Oct 13 2009We present an analysis of the neutral hydrogen and stellar populations of elliptical galaxies in the Tal et al. (2009) sample. Our aim is to test their conclusion that the continuing assembly of these galaxies at z~0 is essentially gas-free and not accompanied ... More Understanding Human-Centric Images: From Geometry to FashionDec 14 2015Understanding humans from photographs has always been a fundamental goal of computer vision. In this thesis we have developed a hierarchy of tools that cover a wide range of topics with the objective of understanding humans from monocular RGB image: from ... More On the tree-depth of Random GraphsApr 12 2011Feb 15 2012The tree-depth is a parameter introduced under several names as a measure of sparsity of a graph. We compute asymptotic values of the tree-depth of random graphs. For dense graphs, p>> 1/n, the tree-depth of a random graph G is a.a.s. td(G)=n-O(sqrt(n/p)). ... More A minimization approach to hyperbolic Cauchy problemsOct 25 2013Developing an original idea of De Giorgi, we introduce a new and purely variational approach to the Cauchy Problem for a wide class of defocusing hyperbolic equations. The main novel feature is that the solutions are obtained as limits of functions that ... More Rainbow Matchings: existence and countingApr 14 2011A perfect matching M in an edge-colored complete bipartite graph K_{n,n} is rainbow if no pair of edges in M have the same color. We obtain asymptotic enumeration results for the number of rainbow matchings in terms of the maximum number of occurrences ... More Life time evolution of coronal holesJul 05 2019Jul 16 2019We investigate the evolution of eight well-observed persistent coronal holes (CHs) with life spans of 5--12 solar rotations, that were observed between 2010 and 2015. The aim is to increase our understanding of the evolution of CHs, as well as to investigate ... More Modules over Monads and LinearityAug 11 2006May 07 2007Inspired by the classical theory of modules over a monoid, we give a first account of the natural notion of module over a monad. The associated notion of morphism of left modules ("Linear" natural transformations) captures an important property of compatibility ... More Some Riemann Hypotheses from Random Walks over PrimesSep 11 2015Apr 17 2016The aim of this article is to investigate how various Riemann Hypotheses would follow only from properties of the prime numbers. To this end, we consider two classes of $L$-functions, namely, non-principal Dirichlet and those based on cusp forms. The ... More Robust minimal matching rules for quasicrystalsSep 27 2018We propose a unified framework for dealing with matching rules of quasiperiodic patterns, relevant for both tiling models and real world quasicrystals. The approach is intended for extraction and validation of a minimal set of matching rules, directly ... More Improved Algorithms for MST and Metric-TSP InterdictionMay 31 2017We consider the {\em MST-interdiction} problem: given a multigraph $G = (V, E)$, edge weights $\{w_e\geq 0\}_{e \in E}$, interdiction costs $\{c_e\geq 0\}_{e \in E}$, and an interdiction budget $B\geq 0$, the goal is to remove a set $R\subseteq E$ of ... More