Results for "Marc Toussaint"

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Learning a world model and planning with a self-organizing, dynamic neural systemJun 11 2003We present a connectionist architecture that can learn a model of the relations between perceptions and actions and use this model for behavior planning. State representations are learned with a growing self-organizing layer which is directly coupled ... More
Newton methods for k-order Markov Constrained Motion ProblemsJul 01 2014This is a documentation of a framework for robot motion optimization that aims to draw on classical constrained optimization methods. With one exception the underlying algorithms are classical ones: Gauss-Newton (with adaptive step size and damping), ... More
A Novel Augmented Lagrangian Approach for Inequalities and Convergent Any-Time Non-Central UpdatesDec 14 2014Motivated by robotic trajectory optimization problems we consider the Augmented Lagrangian approach to constrained optimization. We first propose an alternative augmentation of the Lagrangian to handle the inequality case (not based on slack variables) ... More
Lectures on Reduce and Maple at UAM I - MexicoMay 25 2001These lectures give a brief introduction to the Computer Algebra systems Reduce and Maple. The aim is to provide a systematic survey of most important commands and concepts. In particular, this includes a discussion of simplification schemes and the handling ... More
Self-adaptive exploration in evolutionary searchFeb 05 2001We address a primary question of computational as well as biological research on evolution: How can an exploration strategy adapt in such a way as to exploit the information gained about the problem at hand? We first introduce an integrated formalism ... More
The structure of evolutionary exploration: On crossover, buildings blocks and Estimation-Of-Distribution AlgorithmsDec 11 2002The notion of building blocks can be related to the structure of the offspring probability distribution: loci of which variability is strongly correlated constitute a building block. We call this correlated exploration. With this background we analyze ... More
Trajectory-Based Off-Policy Deep Reinforcement LearningMay 14 2019Policy gradient methods are powerful reinforcement learning algorithms and have been demonstrated to solve many complex tasks. However, these methods are also data-inefficient, afflicted with high variance gradient estimates, and frequently get stuck ... More
Neutrality: A Necessity for Self-AdaptationApr 16 2002Self-adaptation is used in all main paradigms of evolutionary computation to increase efficiency. We claim that the basis of self-adaptation is the use of neutrality. In the absence of external control neutrality allows a variation of the search distribution ... More
On Classes of Functions for which No Free Lunch Results HoldAug 21 2001In a recent paper it was shown that No Free Lunch results hold for any subset F of the set of all possible functions from a finite set X to a finite set Y iff F is closed under permutation of X. In this article, we prove that the number of those subsets ... More
Planning with Noisy Probabilistic Relational RulesJan 16 2014Noisy probabilistic relational rules are a promising world model representation for several reasons. They are compact and generalize over world instantiations. They are usually interpretable and they can be learned effectively from the action experiences ... More
Recent Results on No-Free-Lunch Theorems for OptimizationMar 31 2003The sharpened No-Free-Lunch-theorem (NFL-theorem) states that the performance of all optimization algorithms averaged over any finite set F of functions is equal if and only if F is closed under permutation (c.u.p.) and each target function in F is equally ... More
Kinematic Morphing Networks for Manipulation Skill TransferMar 05 2018The transfer of a robot skill between different geometric environments is non-trivial since a wide variety of environments exists, sensor observations as well as robot motions are high-dimensional, and the environment might only be partially observed. ... More
Advancing Bayesian Optimization: The Mixed-Global-Local (MGL) Kernel and Length-Scale Cool DownDec 09 2016Bayesian Optimization (BO) has become a core method for solving expensive black-box optimization problems. While much research focussed on the choice of the acquisition function, we focus on online length-scale adaption and the choice of kernel function. ... More
Path Integral Control by Reproducing Kernel Hilbert Space EmbeddingAug 13 2012We present an embedding of stochastic optimal control problems, of the so called path integral form, into reproducing kernel Hilbert spaces. Using consistent, sample based estimates of the embedding leads to a model free, non-parametric approach for calculation ... More
The Advantage of Cross Entropy over Entropy in Iterative Information GatheringSep 26 2014Sep 16 2015Gathering the most information by picking the least amount of data is a common task in experimental design or when exploring an unknown environment in reinforcement learning and robotics. A widely used measure for quantifying the information contained ... More
Approximate Inference and Stochastic Optimal ControlSep 20 2010We propose a novel reformulation of the stochastic optimal control problem as an approximate inference problem, demonstrating, that such a interpretation leads to new practical methods for the original problem. In particular we characterise a novel class ... More
Hierarchical POMDP Controller Optimization by Likelihood MaximizationJun 13 2012Planning can often be simpli ed by decomposing the task into smaller tasks arranged hierarchically. Charlin et al. [4] recently showed that the hierarchy discovery problem can be framed as a non-convex optimization problem. However, the inherent computational ... More
On the Fundamental Importance of Gauss-Newton in Motion OptimizationMay 30 2016Hessian information speeds convergence substantially in motion optimization. The better the Hessian approximation the better the convergence. But how good is a given approximation theoretically? How much are we losing? This paper addresses that question ... More
Physical problem solving: Joint planning with symbolic, geometric, and dynamic constraintsJul 25 2017In this paper, we present a new task that investigates how people interact with and make judgments about towers of blocks. In Experiment~1, participants in the lab solved a series of problems in which they had to re-configure three blocks from an initial ... More
Probabilistic Recurrent State-Space ModelsJan 31 2018Feb 10 2018State-space models (SSMs) are a highly expressive model class for learning patterns in time series data and for system identification. Deterministic versions of SSMs (e.g. LSTMs) proved extremely successful in modeling complex time series data. Fully ... More
Glueballs and Hybrids (Gluons as Constituents)Sep 10 1999Sep 16 1999After a brief introduction to hybrid and glueball source operators, I summarize recent lattice results for these particles.
Statistical mechanics of interacting fiber bundlesNov 06 2006We consider quasistatic fiber bundle models with interactions. Classical load sharing rules are considered, i.e. local, global or decaying as a power-law of distance. All fibers are identically elastic, initially intact, and break at a random threshold ... More
On the Cartesian Skeleton and the Factorization of the Strong Product of DigraphsJan 20 2014The three standard products (the Cartesian, the direct and the strong product) of undirected graphs have been wellinvestigated, unique prime factor decomposition (PFD) are known and polynomial time algorithms have been established for determining the ... More
Decoding binary Reed-Muller codes via Groebner basesAug 29 2018The binary Reed-Muller codes can be characterized as the radical powers of a modular algebra. We use the Groebner bases to decode these codes.
Spectrum Results with Kogut-Susskind QuarksOct 04 2001Nov 27 2001I summarize recent developments in spectrum calculations using Kogut-Susskind quarks. Theoretical developments include one-loop computations with improved actions. I present some recent simulation results, mostly from a MILC collaboration project using ... More
Scaling functions for O(4) in three dimensionsJul 31 1996Monte Carlo simulation using a cluster algorithm is used to compute the scaling part of the free energy for a three dimensional O(4) spin model. The results are relevant for analysis of lattice studies of high temperature QCD.
Standard Bases for Linear Codes over Prime FieldsAug 18 2017It is known that a linear code can be represented by a binomial ideal. In this paper, we give standard bases for the ideals in a localization of the multivariate polynomial ring in the case of linear codes over prime fields.
On the Complexity of Recognizing S-composite and S-prime GraphsMay 04 2012Jan 16 2013S-prime graphs are graphs that cannot be represented as nontrivial subgraphs of nontrivial Cartesian products of graphs, i.e., whenever it is a subgraph of a nontrivial Cartesian product graph it is a subgraph of one the factors. A graph is S-composite ... More
Loopy annealing belief propagation for vertex cover and matching: convergence, LP relaxation, correctness and Bethe approximationJan 30 2014Jul 07 2014For the minimum cardinality vertex cover and maximum cardinality matching problems, the max-product form of belief propagation (BP) is known to perform poorly on general graphs. In this paper, we present an iterative loopy annealing BP (LABP) algorithm ... More
Spatial NetworksOct 02 2010Nov 04 2010Complex systems are very often organized under the form of networks where nodes and edges are embedded in space. Transportation and mobility networks, Internet, mobile phone networks, power grids, social and contact networks, neural networks, are all ... More
Spheroid and disk signatures in galaxy bulgesJan 31 2003Recent progress on the structure and dynamics of bulges is reviewed. Those aspects that link galaxy bulges either to oblate spheroids akin to elliptical galaxies or to rapidly-rotating, flattened systems more nearly resembling the products of disk internal ... More
Two tails in NGC 3656, and the major merger origin of shell and minor axis dust lane ellipticalsJul 01 1997I report on the discovery of two faint (~ 26.8 Rmag/arcsec^2) tidal tails around the shell elliptical NGC 3656 (Arp 155). This galaxy had previously been interpreted as a case of accretion, or minor merger. The two tidal tails are inconsistent with a ... More
The anomalous magnetic moment of the muon: a theoretical introductionJul 18 2003These notes, based on the lectures delivered at the 2003 Schladming School of Theoretical Physics, provide an introduction to the theory of the anomalous magnetic moments of the muon and of the electron.
Experimental determination of Chiral Symmetry Breaking ParametersMay 27 1993In the low energy domain, Chiral Perturbation Theory parametrizes the small chiral symmetry breaking effects, produced by the quark masses $m_u$, $m_d$ and $m_s$, in terms of order parameters of massless QCD. The latter can then, in principle, be measured ... More
Tau Decays to Mu + Eta in Supersymmetric ModelsJul 10 2002Jul 31 2002The existence of large \nu_\mu-\nu_\tau mixing suggests the likelihood of large smuon-stau mixing in supersymmetric models, leading to \mu and \tau number violation. In addition to interesting signatures in slepton and neutralino production and decay, ... More
Precise Vacuum Stability Bound in the Standard ModelJul 27 1993In the standard model, a lower bound to the Higgs mass (for a given top quark mass) exists if one requires that the standard model vacuum be stable. This bound is calculated as precisely as possible, including the most recent values of the gauge couplings, ... More
Scalar-Mediated Flavor-Changing Neutral CurrentsSep 30 1998The simplest extension of the standard model involves adding a scalar doublet--the so-called two-Higgs model. In general, the additional scalar will mediate tree-level flavor-changing neutral currents. Although one can arbitrarily impose a discrete symmetry ... More
SUSY GUTs without light Higgs bosonsJun 08 1994Jun 14 1994There are two different types of perturbative unification in SUSY GUTs. Perturbative gauge unification is necessary for the extremely successful prediction of $\sin^2\theta_w$. ``Perturbative validity'' requires that {\it all} couplings (not just the ... More
Classification of vertex-transitive cubic partial cubesSep 15 2015Jul 21 2016Partial cubes are graphs isometrically embeddable into hypercubes. In this paper it is proved that every cubic, vertex-transitive partial cube is isomorphic to one of the following graphs: $K_2 \, \square \, C_{2n}$, for some $n\geq 2$, the generalized ... More
Stability of global equilibrium for the multi-species Boltzmann equation in $L^\infty$ settingsMar 04 2016Jul 19 2016We prove the stability of global equilibrium in a multi-species mixture, where the different species can have different masses, on the $3$-dimensional torus. We establish stability estimates in $L^\infty_{x,v}(w)$ where $w=w(v)$ is either polynomial or ... More
OBDDs and (Almost) $k$-wise Independent Random VariablesApr 15 2015OBDD-based graph algorithms deal with the characteristic function of the edge set E of a graph $G = (V,E)$ which is represented by an OBDD and solve optimization problems by mainly using functional operations. We present an OBDD-based algorithm which ... More
Computing asymptotic invariants with the Ricci tensor on asymptotically flat and hyperbolic manifoldsMar 02 2015Apr 22 2016We prove in a simple and coordinate-free way the equivalence bteween the classical definitions of the mass or the center of mass of an asymptotically flat manifold and their alternative definitions depending on the Ricci tensor and conformal Killing fields. ... More
The Muon Anomalous Magnetic MomentDec 03 2014The calculations entering the prediction of the standard model value for the anomalous magnetic moment of the muon $a_\mu$ are reviewed, and compared to the very accurate experimental measurement. The situation for the electron is discussed in parallel. ... More
Instantaneous exponential lower bound for solutions to the Boltzmann equation with Maxwellian diffusion boundary conditionsOct 22 2014Nov 05 2014We prove the immediate appearance of an exponential lower bound, uniform in time and space, for continuous mild solutions to the full Boltzmann equation in a $C^2$ convex bounded domain with the physical Maxwellian diffusion boundary conditions, under ... More
Alternative determinism principle for topological analysis of chaosMar 04 2005Aug 31 2006The topological analysis of chaos based on a knot-theoretic characterization of unstable periodic orbits has proved a powerful method, however knot theory can only be applied to three-dimensional systems. Still, the core principles upon which this approach ... More
Structure of Optimal Transport Networks Subject to a Global ConstraintAug 09 2006Sep 07 2010The structure of pipe networks minimizing the total energy dissipation rate is studied analytically. Among all the possible pipe networks that can be built with a given total pipe volume (or pipe lateral surface area), the network which minimizes the ... More
Architecture of optimal transport networksApr 06 2005We analyze the structure of networks minimizing the global resistance to flow (or dissipated energy) with respect to two different constraints: fixed total channel volume and fixed total channel surface area. First, we determine the shape of channels ... More
Statistical Mechanics of Two-dimensional FoamsSep 07 2010The methods of statistical mechanics are applied to two-dimensional foams under macroscopic agitation. A new variable -- the total cell curvature -- is introduced, which plays the role of energy in conventional statistical thermodynamics. The probability ... More
In vivo compaction dynamics of bacterial DNA: A fingerprint of DNA/RNA demixing ?Sep 26 2016The volume occupied by unconstrained bacterial DNA in physiological solutions exceeds 1000 times the volume of the cell. Still, it is confined to a well defined region of the cell called the nucleoid, which occupies only a fraction of the cell volume. ... More
Subderivative-subdifferential duality formulaNov 12 2016We provide a formula linking the radial subderivative to other subderivatives and subdifferentials for arbitrary extended real-valued lower semicontinuous functions.
Cosmetic contact surgeries along transverse knots and the knot complement problemMar 16 2017We study cosmetic contact surgeries along transverse knots in the standard contact 3-sphere, i.e. contact surgeries that yield again the standard contact 3-sphere. The main result is that we can exclude non-trivial cosmetic contact surgeries (in sufficiently ... More
Dark Matter 2014Jan 06 2015This article gives an overview on the status of experimental searches for dark matter at the end of 2014. The main focus is on direct searches for weakly interacting massive particles (WIMPs) using underground-based low-background detectors, especially ... More
Dark Matter 2013Oct 19 2013Nov 28 2013This article reviews the status of the exciting and fastly evolving field of dark matter research as of summer 2013, when it was discussed at ICRC 2013 in Rio de Janeiro. It focuses on the three main avenues to detect WIMP dark matter: direct detection, ... More
Dark Matter Search with liquid Noble GasesJun 11 2012Dark matter detectors using the liquid noble gases xenon and argon as WIMP targets have evolved rapidly in the last decade and will continue to play a major role in the field. Due to the possibility to scale these detectors to larger masses relatively ... More
Counting Restricted Homomorphisms via Möbius Inversion over Matroid LatticesJun 26 2017We present a framework for the complexity classification of parameterized counting problems that can be formulated as the summation over the numbers of homomorphisms from small pattern graphs H_1,...,H_l to a big host graph G with the restriction that ... More
Revisiting Clifford AlgebrasAug 16 2017This paper is divided in three parts. In the first part, I study the Clifford algebra associated to the hessian of a functional $f$ defined on an open subset of $\mathbb{R}^n$ \ and the Clifford algebra associated to the hessian of the Legendre transform ... More
Koszul Duality and Soergel Bimodules for Dihedral GroupsApr 24 2015We show that the endomorphism ring of the projective generator in the category of Soergel modules (for dihedral groups) is Koszul self-dual.
Fermions in the pseudoparticle approachApr 23 2007The pseudoparticle approach is a numerical technique to compute path integrals without discretizing spacetime. The basic idea is to integrate over those field configurations, which can be represented by a sum of a fixed number of localized building blocks ... More
Classes of confining gauge field configurationsAug 08 2006Dec 18 2006We present a numerical method to compute path integrals in effective SU(2) Yang-Mills theories. The basic idea is to approximate the Yang-Mills path integral by summing over all gauge field configurations, which can be represented as a linear superposition ... More
Inferring Fitness in Finite Populations with Moran-like dynamicsMar 19 2013Oct 23 2013Biological fitness is not an observable quantity and must be inferred from population dynamics. Bayesian inference applied to the Moran process and variants yields a robust inference method that can infer fitness in populations evolving via a Moran dynamic ... More
Brøndsted-Rockafellar property of subdifferentials of prox-bounded functionsJun 23 2013We provide a new proof that the subdifferential of a proper lower semicontinuous convex function on a Banach space is maximal monotone by adapting the pattern commonly used in the Hilbert setting. We then extend the arguments to show more precisely that ... More
The maximum size of short character sumsMay 18 2018In the present note, we prove new lower bounds on large values of character sums $\Delta(x,q):=\max_{\chi \neq \chi_0} \vert \sum_{n\leq x} \chi(n)\vert$ in certain ranges of $x$. Employing an implementation of the resonance method developed in a work ... More
Higher-order Fourier dimension and frequency decompositionsAug 13 2013Jan 18 2015This paper continues work begun in \cite{M1}, in which we introduced a theory of Gowers uniformity norms for singular measures on $\mathbb{R}^d$. There, given a $d$-dimensional measure $\mu$, we introduced a $(k+1)d$-dimensional measure $\triangle^k\mu$, ... More
The homotopy coniveau towerOct 16 2005We examine the "homotopy coniveau tower" for a general cohomology theory on smooth k-schemes and give a new proof that the layers of this tower for K-theory agree with motivic cohomology. In addition, the homotopy coniveau tower agrees with Voevodsky's ... More
Higher Indicators for the Doubles of some Totally Orthogonal GroupsJul 19 2012We investigate the indicators for certain groups of the form $\BZ_k\rtimes D_l$ and their doubles, where $D_l$ is the dihedral group of order $2l$. We subsequently obtain an infinite family of totally orthogonal, completely real groups which are generated ... More
Number of points of Prym varieties over finite fieldsJun 01 2007We establish some upper and lower bounds for the number of rational points of Prym varieties over finite fields.
Gowers norms for singular measuresAug 13 2013Jan 18 2015Gowers introduced the notion of uniformity norm $\|f\|_{U^k(G)}$ of a bounded function $f:G\rightarrow\mathbb{R}$ on an abelian group $G$ in order to provide a Fourier-theoretic proof of Szemeredi's Theorem, that is, that a subset of the integers of positive ... More
Free divisors on metric graphsOct 12 2014On a metric graph we introduce the notion of a free divisor as a replacement for the notion of a base point free complete linear system on a curve. By means of an example we show that the Clifford inequality is the only obstruction for the existence of ... More
Slices and TransfersMar 09 2010We study the slice filtration for S^1-spectra over a field k, and raise a number of questions regardings its properties. We show that the slices, except for the 0th slice, admit a further filtration whose layers are in a natural way the Eilenberg-Maclane ... More
A comparison of motivic and classical homotopy theoriesDec 31 2011Mar 07 2013Let k be an algebraically closed field of characteristic zero. Let SH(k) denote the motivic stable homotopy category of T-spectra over k and SH the classical stable homotopy category. Let c:SH -> SH(k) be the functor induced by sending a space to the ... More
The slice filtration and Grothendieck-Witt groupsDec 27 2010Let k be a perfect field of characteristic different from two. We show that the filtration on the Grothendieck-Witt group GW(k) induced by the slice filtration for the sphere spectrum in the motivic stable homotopy category is the I-adic filtration, where ... More
Algebraic cobordismApr 15 2003Together with F. Morel, we have constructed in \cite{CR, Cobord1, Cobord2} a theory of {\em algebraic cobordism}, an algebro-geometric version of the topological theory of complex cobordism. In this paper, we give a survey of the construction and main ... More
Is the Universe Homogeneous on Large Scales?Oct 19 1996Oct 21 1996This contribution is the affirmative side of a debate held with Dr. L. Pietronero at Princeton in June, 1996. I present the observational evidence that the fractal behavior which characterizes the small scale galaxy distribution does not continue to arbitarily ... More
A new family of periodic functions as explicit roots of a class of polynomial equationsOct 26 2004For any positive integer n, a new family of periodic functions in power series form and of period n is used to solve in closed form a class of polynomial equation of order n. The n roots are the values of the appropriate function from that family taken ... More
Homogenization of linear transport equations. A new approachMay 22 2019The paper is devoted to a new approach of the homogenization of linear transport equations induced by a uniformly bounded sequence of vector fields $b_\epsilon(x)$, the solutions of which $u_\epsilon(t,x)$ agree at $t=0$ with a bounded sequence of $L^p_{\rm ... More
Implicitization using approximation complexesMar 09 2005We present a method for the implicitization problem that goes back to the work of Sederberg and Chen. The formalism we use, with approximation complexes as a key ingredient, is due to Jean-Pierre Jouanolou and was explained in details in this context ... More
The efficient certification of knottedness and Thurston normApr 01 2016We show that the problem of determining whether a knot in the 3-sphere is non-trivial lies in NP. This is a consequence of the following more general result. The problem of determining whether the Thurston norm of a second homology class in a compact ... More
Links with splitting number oneAug 16 2018We provide an algorithm to determine whether a link L admits a crossing change that turns it into a split link, under some fairly mild hypotheses on L. The algorithm also provides a complete list of all such crossing changes. It can therefore also determine ... More
Every knot has characterising slopesJul 03 2017Aug 07 2018Let K be a knot in the 3-sphere. A slope p/q is said to be characterising for K if whenever p/q surgery on K is homeomorphic, via an orientation-preserving homeomorphism, to p/q surgery on another knot K' in the 3-sphere, then K and K' are isotopic. It ... More
Motivic Euler characteristics and Witt-valued characteristic classesJun 26 2018May 19 2019This paper examines a number of related questions about Euler characteristics and characteristic classes with values in Witt cohomology. We establish a motivic version of the Becker-Gottllieb transfer, generalizing a construction of Hoyois. Ananyevskiy's ... More
Simpler, Linear-Time Transitive Orientation via Lexicographic Breadth-First SearchMar 10 2015Comparability graphs are the undirected graphs whose edges can be directed so that the resulting directed graph is transitive. They are related to posets and have applications in scheduling theory. This paper considers the problem of finding a transitive ... More
Topoi of parametrized objectsNov 07 2016We give necessary and sufficient conditions on a presentable infinity-category C so that families of objects of C form an infinity-topos. In particular, we prove a conjecture of Joyal that this is the case whenever C is stable.
DARWINNov 27 2011DARWIN is a design-study for a next-to-next generation experiment to directly detect WIMP dark matter in a detector based on a liquid xenon/liquid argon two-phase time projection chamber. This article describes the project, its goals and challenges, and ... More
The Coleman-Weinberg Phase Transition in Extended Higgs ModelsJul 16 1996In Coleman-Weinberg symmetry breaking, all dimensionful parameters vanish and the symmetry is broken by loop corrections. Before Coleman-Weinberg symmetry breaking in the Standard Model was experimentally ruled out, it had already been excluded on cosmological ... More
Universal Extra Dimensions and Kaluza-Klein Bound StatesSep 02 2004We study the bounds states of the Kaluza-Klein (KK) excitations of quarks in models of Universal Extra Dimensions. Such bound states may be detected at future lepton colliders in the cross section for the pair-production of KK-quarks near threshold. For ... More
Classification in Feature-based Default Inheritance HierarchiesJun 04 1996Increasingly, inheritance hierarchies are being used to reduce redundancy in natural language processing lexicons. Systems that utilize inheritance hierarchies need to be able to insert words under the optimal set of classes in these hierarchies. In this ... More
Group Theory and Grammatical DescriptionMay 07 1998This paper presents a model for linguistic description based on group theory. A grammar in this model, or "G-grammar", is a collection of lexical expressions which are products of logical forms, phonological forms, and their inverses. Phrasal descriptions ... More
Morphological Cues for Lexical SemanticsJun 04 1996Most natural language processing tasks require lexical semantic information. Automated acquisition of this information would thus increase the robustness and portability of NLP systems. This paper describes an acquisition method which makes use of fixed ... More
NumGfun: a Package for Numerical and Analytic Computation with D-finite FunctionsFeb 16 2010May 31 2010This article describes the implementation in the software package NumGfun of classical algorithms that operate on solutions of linear differential equations or recurrence relations with polynomial coefficients, including what seems to be the first general ... More
Two-photon physicsJan 26 2006It is reviewed how Compton scattering sum rules relate low-energy nucleon structure quantities to the nucleon excitation spectrum. In particular, the GDH sum rule and recently proposed extensions of it will be discussed. These extensions are sometimes ... More
Coordination in Network Security Games: a Monotone Comparative Statics ApproachAug 20 2012Malicious softwares or malwares for short have become a major security threat. While originating in criminal behavior, their impact are also influenced by the decisions of legitimate end users. Getting agents in the Internet, and in networks in general, ... More
Betweenness Centrality in Large Complex NetworksSep 18 2003May 13 2004We analyze the betweenness centrality (BC) of nodes in large complex networks. In general, the BC is increasing with connectivity as a power law with an exponent $\eta$. We find that for trees or networks with a small loop density $\eta=2$ while a larger ... More
Crossover from Scale-Free to Spatial NetworksDec 04 2002Sep 22 2003In many networks such as transportation or communication networks, distance is certainly a relevant parameter. In addition, real-world examples suggest that when long-range links are existing, they usually connect to hubs-the well connected nodes. We ... More
Electromagnetic Corrections to Low-Energy pi-pi ScatteringDec 21 1999Electromagnetic corrections to the low-energy pi+ pi- -> pi0 pi0 scattering amplitude at next-to-leading order in the chiral expansion are reviewed. Their effects on the corresponding scattering lengths are estimated and compared to the two-loop strong ... More
A note on the Declarative reading(s) of Logic ProgrammingMar 13 2000This paper analyses the declarative readings of logic programming. Logic programming - and negation as failure - has no unique declarative reading. One common view is that logic programming is a logic for default reasoning, a sub-formalism of default ... More
Model Prediction for the Transverse Single Target-Spin Asymmetry in inclusive DISMar 05 2013The single-spin asymmetry of unpolarized leptons scattering deep-inelastically off transversely polarized nucleons is discussed. This observable is generated by a two-photon exchange between lepton and nucleon. In a partonic description of the asymmetry ... More
The local renormalization of super-Yang-Mills theoriesFeb 11 2016May 11 2016We show how to consistently renormalize $\mathcal{N} = 1$ and $\mathcal{N} = 2$ super-Yang-Mills theories in flat space with a local (i.e. space-time-dependent) renormalization scale in a holomorphic scheme. The action gets enhanced by a term proportional ... More
The six operations in equivariant motivic homotopy theorySep 07 2015Sep 27 2016We introduce and study the homotopy theory of motivic spaces and spectra parametrized by quotient stacks [X/G], where G is a linearly reductive linear algebraic group. We extend to this equivariant setting the main foundational results of motivic homotopy ... More
The fixed points of the circle action on Hochschild homologyJun 23 2015This note proves that the negative cyclic homology of a differential graded k-algebra, for k a commutative ring, coincides with the homotopy fixed points of the canonical circle action on its Hochschild complex. This is probably well-known.
A Closer Look at the Mond No-Go Statement for Purely Metric FormulationsOct 20 2003We reexamine the assumptions made in arriving at a no-go statement for purely metric formulations of MOND. Removing the requirement of gravitational stability at appropriate scales gives life to the possibility of a purely metric theory of MOND.