Results for "Pascal Van Hentenryck"

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Unit Commitment With Gas Network AwarenessFeb 08 2019Recent changes in the fuel mix for electricity generation and, in particular, the increase in Gas-Fueled Power Plants (GFPP), have created significant interdependencies between the electrical power and natural gas transmission systems. However, despite ... More
Benders Decomposition for a Class of Mathematical Programs with Constraints on Dual VariablesFeb 12 2019Interdependent systems with mutual feedback are best represented as a multi-level mathematical programming, in which the leader decisions determine the follower operations, which subsequently affect the leader operations. For instance, a recent paper ... More
CPBVP: A Constraint-Programming Framework for Bounded Program VerificationJul 15 2008This paper studies how to verify the conformity of a program with its specification and proposes a novel constraint-programming framework for bounded program verification (CPBPV). The CPBPV framework uses constraint stores to represent the specification ... More
Comparison between CPBPV, ESC/Java, CBMC, Blast, EUREKA and Why for Bounded Program VerificationAug 11 2008This report describes experimental results for a set of benchmarks on program verification. It compares the capabilities of CPBVP "Constraint Programming framework for Bounded Program Verification" [4] with the following frameworks: ESC/Java, CBMC, Blast, ... More
Differential Privacy for Power Grid ObfuscationJan 21 2019The availability of high-fidelity energy networks brings significant value to academic and commercial research. However, such releases also raise fundamental concerns related to privacy and security as they can reveal sensitive commercial information ... More
Communication-Constrained Expansion Planning for Resilient Distribution SystemsJan 10 2018Distributed generation and remotely controlled switches have emerged as important technologies to improve the resiliency of distribution grids against extreme weather-related disturbances. Therefore it becomes impor- tant to study how best to place them ... More
Popularity Signals in Trial-Offer Markets with Social Influence and Position BiasDec 22 2015Nov 03 2017This paper considers trial-offer markets where consumer preferences are modeled by a multinomial logit with social influence and position bias. The social signal for a product is given by its current market share raised to power r (or equivalently the ... More
On the Optimality and Predictability of Cultural Markets with Social InfluenceMay 11 2015May 25 2015Social influence is ubiquitous in cultural markets, from book recommendations in Amazon, to song popularities in iTunes and the ranking of newspaper articles in the online edition of the New York Times to mention only a few. Yet social influence is often ... More
Modeling Stated Preference for Mobility-on-Demand Transit: A Comparison of Machine Learning and Logit ModelsNov 04 2018Logit models are usually applied when studying individual travel behavior, i.e., to predict travel mode choice and to gain behavioral insights on traveler preferences. Recently, some studies have applied machine learning to model travel mode choice and ... More
Efficient Dynamic Compressor Optimization in Natural Gas Transmission SystemsNov 24 2015The growing reliance of electric power systems on gas-fired generation to balance intermittent sources of renewable energy has increased the variation and volume of flows through natural gas transmission pipelines. Adapting pipeline operations to maintain ... More
Mobility-on-demand versus fixed-route transit systems: an evaluation of traveler preferences in low-income communitiesJan 22 2019Emerging transportation technologies, such as ride-hailing and autonomous vehicles, are disrupting the transportation sector and transforming public transit. Some transit observers envision future public transit to be integrated transit systems with fixed-route ... More
Expecting to be HIP: Hawkes Intensity Processes for Social Media PopularityFeb 19 2016Sep 08 2017Modeling and predicting the popularity of online content is a significant problem for the practice of information dissemination, advertising, and consumption. Recent work analyzing massive datasets advances our understanding of popularity, but one major ... More
Interdependent Scheduling GamesMay 31 2016We propose a model of interdependent scheduling games in which each player controls a set of services that they schedule independently. A player is free to schedule his own services at any time; however, each of these services only begins to accrue reward ... More
A Microkernel Architecture for Constraint ProgrammingJan 21 2014This paper presents a microkernel architecture for constraint programming organized around a number of small number of core functionalities and minimal interfaces. The architecture contrasts with the monolithic nature of many implementations. Experimental ... More
A constraint satisfaction approach to the robust spanning tree problem with interval dataDec 12 2012Robust optimization is one of the fundamental approaches to deal with uncertainty in combinatorial optimization. This paper considers the robust spanning tree problem with interval data, which arises in a variety of telecommunication applications. It ... More
Domain Views for Constraint ProgrammingJan 21 2014Views are a standard abstraction in constraint programming: They make it possible to implement a single version of each constraint, while avoiding to create new variables and constraints that would slow down propagation. Traditional constraint-programming ... More
A Linear-Programming Approximation of AC Power FlowsJun 16 2012Aug 06 2013Linear active-power-only DC power flow approximations are pervasive in the planning and control of power systems. However, these approximations fail to capture reactive power and voltage magnitudes, both of which are necessary in many applications to ... More
Bargaining Mechanisms for One-Way GamesJul 25 2015We introduce one-way games, a framework motivated by applications in large-scale power restoration, humanitarian logistics, and integrated supply-chains. The distinguishable feature of the games is that the payoff of some player is determined only by ... More
Polynomial SDP Cuts for Optimal Power FlowOct 27 2015The use of convex relaxations has lately gained considerable interest in Power Systems. These relaxations play a major role in providing global optimality guarantees for non-convex optimization problems. For the Optimal Power Flow (OPF) problem, the Semi-Definite ... More
Strengthening the SDP Relaxation of AC Power Flows with Convex Envelopes, Bound Tightening, and Lifted Nonlinear CutsDec 15 2015Jan 05 2016This paper considers state-of-the-art convex relaxations for the AC power flow equations and introduces new valid cuts based on convex envelopes and lifted nonlinear constraints. These valid linear inequalities strengthen existing semidefinite and quadratic ... More
The Complexity of DC-Switching ProblemsNov 17 2014This report provides a comprehensive complexity study of line switching in the Linear DC model for the feasibility problem and the optimization problems of maximizing the load that can be served (maximum switching flow, MSF) and minimizing generation ... More
Sonet Network Design ProblemsOct 07 2009This paper presents a new method and a constraint-based objective function to solve two problems related to the design of optical telecommunication networks, namely the Synchronous Optical Network Ring Assignment Problem (SRAP) and the Intra-ring Synchronous ... More
Trial-Offer Markets with ContinuationOct 05 2016Trial-offer markets, where customers can sample a product before deciding whether to buy it, are ubiquitous in the online experience. Their static and dynamic properties are often studied by assuming that consumers follow a multinomial logit model and ... More
Modeling Heterogeneity in Mode-Switching Behavior Under a Mobility-on-Demand Transit System: An Interpretable Machine Learning ApproachFeb 08 2019Recent years have witnessed an increased focus on interpretability and the use of machine learning to inform policy analysis and decision making. This paper applies machine learning to examine travel behavior and, in particular, on modeling changes in ... More
Benders Decomposition for the Design of a Hub and Shuttle Public Transit SystemDec 30 2015The BusPlus project aims at improving the off-peak hours public transit service in Canberra, Australia. To address the difficulty of covering a large geographic area, BusPlus proposes a hub and shuttle model consisting of a combination of a few high-frequency ... More
Simulation and Analysis of Container Freight Train Operations at Port BotanyDec 10 2015Dec 22 2015Over two million containers crossed the docks at Sydney's Port Botany in 2011/12; a figure that is forecast increase more than threefold by the end of the next decade. To cope with such large growth in volumes the NSW Government plans to double rail mode ... More
The Benefits of Segmentation in Trial-Offer Markets with Social Influence and Position BiasNov 03 2015The purchasing behaviour of consumers is often influenced by numerous factors, including the visibility of the products and the influence of other customers through their own purchases or their recommendations. Motivated by trial-offer and freemium markets ... More
The Complexity of Switching and FACTS Maximum-Potential-Flow ProblemsJul 17 2015This papers considers the problem of maximizing the load that can be served by a power network. We use the commonly accepted Linear DC power network model and consider wo configuration options: switching lines and using FACTS devices. We present the first ... More
A Constraint Programming Approach for Non-Preemptive Evacuation SchedulingMay 11 2015Large-scale controlled evacuations require emergency services to select evacuation routes, decide departure times, and mobilize resources to issue orders, all under strict time constraints. Existing algorithms almost always allow for preemptive evacuation ... More
AC-Feasibility on Tree Networks is NP-HardOct 30 2014Recent years have witnessed significant interest in convex relaxations of the power flows, several papers showing that the second-order cone relaxation is tight for tree networks under various conditions on loads or voltages. This paper shows that AC-feasibility, ... More
DistFlow Extensions for AC Transmission SystemsMay 27 2015Convex relaxations of the power flow equations and, in particular, the Semi-Definite Programming (SDP), Second-Order Cone (SOC), and Convex DistFlow (CDF) relaxations, have attracted significant interest in recent years. Thus far, studies of the CDF model ... More
The QC Relaxation: Theoretical and Computational Results on Optimal Power FlowFeb 27 2015Jul 29 2015Convex relaxations of the power flow equations and, in particular, the Semi-Definite Programming (SDP) and Second-Order Cone (SOC) relaxations, have attracted significant interest in recent years. The Quadratic Convex (QC) relaxation is a departure from ... More
Measuring and Optimizing Cultural MarketsAug 07 2014May 25 2015Social influence has been shown to create significant unpredictability in cultural markets, providing one potential explanation why experts routinely fail at predicting commercial success of cultural products. To counteract the difficulty of making accurate ... More
Sequence-Based Abstract Interpretation of PrologOct 19 2000Many abstract interpretation frameworks and analyses for Prolog have been proposed, which seek to extract information useful for program optimization. Although motivated by practical considerations, notably making Prolog competitive with imperative languages, ... More
Popularity Signals in Trial-Offer MarketsDec 22 2015Dec 23 2015This paper considers trial-offer and freemium markets where consumer preferences are modeled by a multinomial logic model with social influence and position bias. The social signal for a product i is its market share raised to some power r. The paper ... More
A Local Search Modeling for Constrained Optimum Paths Problems (Extended Abstract)Oct 07 2009Constrained Optimum Path (COP) problems appear in many real-life applications, especially on communication networks. Some of these problems have been considered and solved by specific techniques which are usually difficult to extend. In this paper, we ... More
Crowdsourcing DilemmaApr 12 2013Feb 22 2014Crowdsourcing offers unprecedented potential for solving tasks efficiently by tapping into the skills of large groups of people. A salient feature of crowdsourcing---its openness of entry---makes it vulnerable to malicious behavior. Such behavior took ... More
Propagating Regular Counting ConstraintsSep 27 2013Constraints over finite sequences of variables are ubiquitous in sequencing and timetabling. Moreover, the wide variety of such constraints in practical applications led to general modelling techniques and generic propagation algorithms, often based on ... More
Optimizing Expected Utility in a Multinomial Logit Model with Position Bias and Social InfluenceNov 02 2014Nov 06 2014Motivated by applications in retail, online advertising, and cultural markets, this paper studies how to find the optimal assortment and positioning of products subject to a capacity constraint. We prove that the optimal assortment and positioning can ... More
Network Flow and Copper Plate Relaxations for AC Transmission SystemsJun 17 2015Nov 12 2015Nonlinear convex relaxations of the power flow equations and, in particular, the Semi-Definite Programming (SDP), Convex Quadratic (QC), and Second-Order Cone (SOC) relaxations, have attracted significant interest in recent years. Thus far, little attention ... More
Discontinuity of the Lempert function of the spectral ballNov 19 2008Sep 07 2009We give some further criteria for continuity or discontinuity of the Lempert funtion of the spectral ball $\Omega_n$, with respect to one or both of its arguments, in terms of cyclicity the matrices involved.
Convex Relaxations for Gas Expansion PlanningJun 24 2015Expansion of natural gas networks is a critical process involving substantial capital expenditures with complex decision-support requirements. Given the non-convex nature of gas transmission constraints, global optimality and infeasibility guarantees ... More
Performance of Social Network Sensors During Hurricane SandyFeb 11 2014Jun 20 2014Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow, and a mean to derive early-warning sensors, improving ... More
Linking endogenous and exogenous popularity processes in social mediaFeb 19 2016Jul 20 2016Explaining and predicting the popularity of online multimedia content is an important problem for the practice of information dissemination and consumption. Recent work advances our understanding of popularity, but one important gap remains: to precisely ... More
Nowcasting Disaster DamageApr 26 2015Could social media data aid in disaster response and damage assessment? Countries face both an increasing frequency and intensity of natural disasters due to climate change. And during such events, citizens are turning to social media platforms for disaster-related ... More
Graphical Models for Optimal Power FlowJun 21 2016Optimal power flow (OPF) is the central optimization problem in electric power grids. Although solved routinely in the course of power grid operations, it is known to be strongly NP-hard in general, and weakly NP-hard over tree networks. In this paper, ... More
Cerium: the lithium substitute in post-AGB starsOct 15 2002In this letter we present an alternative identification for the line detected in the spectra of s-process enriched low-mass post-AGB stars around 6708A and which was interpreted in the literature as due to Li. Newly released line lists of lanthanide species ... More
Green functions of the spectral ball and symmetrized polydiskJul 19 2010The Green function of the spectral ball is constant over the isospectral varieties, is never less than the pullback of its counterpart on the symmetrized polydisk, and is equal to it in the generic case where the pole is a cyclic (non-derogatory) matrix. ... More
Hyperspherical Prototype NetworksJan 29 2019This paper introduces hyperspherical prototype networks, which unify regression and classification by prototypes on hyperspherical output spaces. Rather than defining prototypes as the mean output vector over training examples per class, we propose hyperspheres ... More
Activity-Based Search for Black-Box Contraint-Programming SolversMay 31 2011Robust search procedures are a central component in the design of black-box constraint-programming solvers. This paper proposes activity-based search, the idea of using the activity of variables during propagation to guide the search. Activity-based search ... More
Gravitational lensing in WDM cosmologies: The cross section for giant arcsApr 07 2014The nature of the dark sector of the Universe remains one of the outstanding problems in modern cosmology, with the search for new observational probes guiding the development of the next generation of observational facilities. Clues come from tension ... More
Negative diffraction pattern dynamics in nonlinear cavities with left-handed materialsMar 02 2010Mar 02 2010We study a ring cavity filled with a slab of a right-handed material and a slab of a left-handed material. Both layers are assumed to be nonlinear Kerr media. First, we derive a model for the propagation of light in a left-handed material. By constructing ... More
Une grammaire formelle du créole martiniquais pour la génération automatiqueOct 07 2008In this article, some first elements of a computational modelling of the grammar of the Martiniquese French Creole dialect are presented. The sources of inspiration for the modelling is the functional description given by Damoiseau (1984), and Pinalie's ... More
The attractor structure of logarithmic iterations in the complex planeDec 29 2010We use the methods of empirical mathematics to show that iterative logarithmic operations will result in an attractor point on the complex plane. Moreover, we demonstrate that different bases converge onto different attractors. Finally, we elicit the ... More
On the $\bar{\mathbb F}_l$-cohomology of a simple unitary Shimura varietyDec 07 2015Apr 06 2016We study the torsion cohomology classes of Shimura varieties of type Kottwitz-Harris-Taylor and we show that " up to an arbitrary place " one can raise them to an automorphic representation. In application, to any mod $l$ system of Hecke eigenvalues appearing ... More
A Semantics-based Communication System for Dysphasic SubjectsMar 12 1997Dysphasic subjects do not have complete linguistic abilities and only produce a weakly structured, topicalized language. They are offered artificial symbolic languages to help them communicate in a way more adapted to their linguistic abilities. After ... More
Evolution of the Magnetic Field Distribution of Active RegionsSep 13 2016Aims. Although the temporal evolution of active regions (ARs) is relatively well understood, the processes involved continue to be the subject of investigation. We study how the magnetic field of a series of ARs evolves with time to better characterise ... More
Modelling the Effect of Mass-Draining on Prominence EruptionsJan 30 2019Quiescent solar prominences are observed to exist within the solar atmosphere for up to several solar rotations. Their eruption is commonly preceded by a slow increase in height that can last from hours to days. This increase in the prominence height ... More
On defining irreducibilityJul 01 1999We show that irreducibility is not a first-order definable property of real algebraic varieties. The proof is based on the recent o-minimality result for the exponential function. We conjecture that irreducibility is not a definable property of complex ... More
Kondo screening cloud in a double-quantum dot systemFeb 16 2005We analyze the transport properties of two artificial magnetic impurities coupled togethervia a tunable RKKY interaction mediated by conduction electrons of a finite size one dimensional wire. We show that the sign of the RKKY interaction can be controlled ... More
On Hofmann's bilinear estimateDec 17 2008May 17 2009Using the framework of a previous article joint with Axelsson and McIntosh, we extend to systems two results of S. Hofmann for real symmetric equations and their perturbations going back to a work of B. Dahlberg for Laplace's equation on Lipschitz domains, ... More
A family of tridiagonal pairs and related symmetric functionsApr 17 2006Mar 11 2007A family of tridiagonal pairs which appear in the context of quantum integrable systems is studied in details. The corresponding eigenvalue sequences, eigenspaces and the block tridiagonal structure of their matrix realizations with respect the dual eigenbasis ... More
A Chart-Parsing Algorithm for Efficient Semantic AnalysisSep 02 2002In some contexts, well-formed natural language cannot be expected as input to information or communication systems. In these contexts, the use of grammar-independent input (sequences of uninflected semantic units like e.g. language-independent icons) ... More
Modelling Semantic Association and Conceptual Inheritance for Semantic AnalysisSep 15 2001Allowing users to interact through language borders is an interesting challenge for information technology. For the purpose of a computer assisted language learning system, we have chosen icons for representing meaning on the input interface, since icons ... More
A Layered Grammar Model: Using Tree-Adjoining Grammars to Build a Common Syntactic Kernel for Related DialectsOct 07 2008This article describes the design of a common syntactic description for the core grammar of a group of related dialects. The common description does not rely on an abstract sub-linguistic structure like a metagrammar: it consists in a single FS-LTAG where ... More
Default reasoning over domains and concept hierarchiesSep 01 2004W.C. Rounds and G.-Q. Zhang (2001) have proposed to study a form of disjunctive logic programming generalized to algebraic domains. This system allows reasoning with information which is hierarchically structured and forms a (suitable) domain. We extend ... More
Change of angle in tent spacesJan 20 2011We prove sharp bounds for the equivalence of norms in tent spaces with respect to changes of angles. Some applications are given.
On the Calderón-Zygmund lemma for Sobolev functionsOct 28 2008We correct an inaccuracy in the original proof
The $λ$-invariant measures of subcritical Bienaymé--Galton--Watson processesAug 04 2015Jun 13 2016A $\lambda$-invariant measure of a sub-Markov chain is a left eigenvector of its transition matrix of eigenvalue $\lambda$. In this article, we give an explicit integral representation of the $\lambda$-invariant measures of subcritical Bienaym\'e--Galton--Watson ... More
On Zero Divisors with Small Support in Group Rings of Torsion-Free GroupsFeb 29 2012Kaplanski's Zero Divisor Conjecture envisions that for a torsion-free group G and an integral domain R, the group ring R[G] does not contain non-trivial zero divisors. We define the length of an element a in R[G] as the minimal non-negative integer k ... More
Confirmation of the compactness of a z=1.91 quiescent galaxy with Hubble Space Telescope's Wide Field Camera 3Apr 08 2010We present very deep Wide Field Camera 3 (WFC3) photometry of a massive, compact galaxy located in the Hubble Ultra Deep Field. This quiescent galaxy has a spectroscopic redshift z=1.91 and has been identified as an extremely compact galaxy by Daddi et ... More
The Hubble Legacy Fields (HLF-GOODS-S) v1.0 Data Products: Combining 2387 Orbits of GOODS-S/CDF-S Region ACS and WFC3/IR ImagesJun 02 2016We have submitted to MAST the 1.0 version data release of the Hubble Legacy Fields (HLF) project covering a 25 x 25 arcmin area over the GOOD-S (ECDF-S) region from the HST archival program AR-13252. The release combines exposures from Hubble's two main ... More
Tracing the Mass Growth and Star Formation Rate Evolution of Massive Galaxies from z~6 to z~1 in the Hubble Ultra-Deep FieldOct 28 2013Oct 30 2013We present an analysis of $\sim$1500 H160-selected photometric galaxies detected to a limiting magnitude of 27.8 in the HUDF, using imaging from the HST WFC3/IR camera in combination with archival UV, optical, and NIR imaging. We fit photometric redshifts ... More
Atomic layer deposition-based tuning of the pore size in mesoporous thin films studied by in situ grazing incidence small angle x-ray scatteringFeb 25 2015Atomic layer deposition (ALD) enables the conformal coating of porous materials, making the technique suitable for pore size tuning at the atomic level, e.g., for applications in catalysis, gas separation and sensing. It is, however, not straightforward ... More
Coronal Elemental Abundances in Solar Emerging Flux RegionsJan 25 2018The chemical composition of solar and stellar atmospheres differs from that of their photospheres. Abundances of elements with low first ionization potential (FIP) are enhanced in the corona relative to high FIP elements with respect to the photosphere. ... More
The Relation Between [OIII]/H$β$ and Specific Star Formation Rate in Galaxies at $z \sim 2$Jun 03 2016Recent surveys have identified a seemingly ubiquitous population of galaxies with elevated [OIII]/H$\beta$ emission line ratios at $z > 1$, though the nature of this phenomenon continues to be debated. The [OIII]/H$\beta$ line ratio is of interest because ... More
Certification of minimal approximant basesFeb 06 2018Considering a given computational problem, a certificate is a piece of additional data that one attaches to the output in order to help verifying that this output is correct. Certificates are often used to make the verification phase significantly more ... More
Polynomial Filtering for Fast Convergence in Distributed ConsensusFeb 27 2008In the past few years, the problem of distributed consensus has received a lot of attention, particularly in the framework of ad hoc sensor networks. Most methods proposed in the literature address the consensus averaging problem by distributed linear ... More
Detecting Robust Patterns in the Spread of Epidemics: A Case Study of Influenza in the United States and FranceJun 22 2008In this paper, the authors develop a method of detecting correlations between epidemic patterns in different regions that are due to human movement and introduce a null model in which the travel-induced correlations are cancelled. They apply this method ... More
Learning Smooth Pattern Transformation ManifoldsDec 23 2011Oct 30 2012Manifold models provide low-dimensional representations that are useful for processing and analyzing data in a transformation-invariant way. In this paper, we study the problem of learning smooth pattern transformation manifolds from image sets that represent ... More
A Study of Image Analysis with Tangent DistanceJan 11 2014Sep 30 2014The computation of the geometric transformation between a reference and a target image, known as registration or alignment, corresponds to the projection of the target image onto the transformation manifold of the reference image (the set of images generated ... More
Circle averages and disjointness in typical flat surfaces on every Teichmueller discOct 20 2015We prove that on the typical flat surface the flow in almost every pair of directions are not isomorphic to each other and are in fact disjoint. We provide an application to the convergence of 'circle averages' for the flow (away from a sequence of radii ... More
On non-autonomous maximal regularity for elliptic operators in divergence formFeb 26 2016May 26 2016We consider the Cauchy problem for non-autonomous forms inducing elliptic operators in divergence form with Dirichlet, Neumann, or mixed boundary conditions on an open subset $\Omega$ $\subseteq$ R n. We obtain maximal regularity in L 2 ($\Omega$) if ... More
Electronic spin precession and interferometry from spin-orbital entanglement in a double quantum dotDec 14 2005Dec 18 2006A double quantum dot inserted in parallel between two metallic leads allows to entangle the electron spin with the orbital (dot index) degree of freedom. An Aharonov-Bohm orbital phase can then be transferred to the spinor wavefunction, providing a geometrical ... More
Interplay between classical magnetic moments and superconductivity in quantum one-dimensional conductors: toward a self-sustained topological Majorana phaseJul 09 2013Oct 06 2013We study a one-dimensional (1D) interacting electronic liquid coupled to a 1D array of classical magnetic moments and to a superconductor. We show that at low energy and temperature the magnetic moments and the electrons become strongly entangled and ... More
The rational homotopy type of a blow-up in the stable caseJun 10 2007Suppose that f:V->W is an embedding of closed oriented manifolds whose normal bundle has the structure of a complex vector bundle. It is well known in both complex and symplectic geometry that one can then construct a manifold W' which is the blow-up ... More
Hypersurfaces d'un fibré vectoriel Riemannien à courbures moyennes verticale et horizontale prescritesJan 30 2016Let M be a compact Riemannian manifold without boundary and let E be a Riemannian vector bundle over M. If $\Sigma$ denotes the sphere subbundle of E, we look for embeddings of $\Sigma$ into E admitting a prescribed mean curvatures of various type.
Bipartite Kneser graphs are HamiltonianMar 31 2015Oct 09 2015For integers $k\geq 1$ and $n\geq 2k+1$ the Kneser graph $K(n,k)$ has as vertices all $k$-element subsets of $[n]:=\{1,2,\ldots,n\}$ and an edge between any two vertices (=sets) that are disjoint. The bipartite Kneser graph $H(n,k)$ has as vertices all ... More
Minimal Asymmetric GraphsMay 04 2016Confirming a conjecture of Ne\v{s}et\v{r}il, we show that up to isomorphism there is only a finite number of finite minimal asymmetric undirected graphs. In fact, there are exactly 18 such graphs. We also show that these graphs are exactly the finite ... More
Veech groups without parabolic elementsMar 02 2005Jun 29 2005We prove that a ``bouillabaisse'' surface (translation surface which has two transverse parabolic elements) has totally real trace field. As a corollary, non trivial Veech groups which have no parabolic elements do exist. The proof follows Veech's viewpoint ... More
Temperature dependence of local states due to S=1/2 impurities and their correlation in a S=1 Heisenberg chainDec 25 1998Jan 19 1999We study the temperature dependence of the low temperature spin configurations, investigating the magnetization profile of the local states due to the impurities and the two point correlation function centered in one of the impurities. This correlation ... More
Efimov Physics: a reviewOct 31 2016This article reviews theoretical and experimental advances in Efimov physics, an array of quantum few-body and many-body phenomena arising for particles interacting via short-range resonant interactions, that is based on the appearance of a scale-invariant ... More
Exact simulation of coined quantum walks with the continuous-time modelJun 13 2016The connection between coined and continuous-time quantum walk models has been addressed in a number of papers. In most of those studies, the continuous-time model is derived from coined quantum walks by employing dimensional reduction and taking appropriate ... More
Velocity-correlation distributions in granular systemsJun 24 2008We investigate the velocity-correlation distributions after $n$ collisions of a tagged particle undergoing binary collisions. Analytical expressions are obtained in any dimension for the velocity-correlation distribution after the first-collision as well ... More
Quasi-gaussian velocity distribution of a vibrated granular bilayer systemOct 19 2007Oct 24 2008We show by using a Discrete Element Method that a bilayer of vibrated granular bidisperse spheres exhibits the striking feature that the horizontal velocity distribution of the top layer particles has a quasi-Gaussian shape, whereas that of the bottom ... More
The angular sizes of dwarf stars and subgiants - Non-linear surface brightness relations in BVRcIc from interferometrySep 10 2008Context: The prediction of stellar angular diameters from broadband photometry plays an important role for different applications. In particular, long-baseline interferometry, gravitational microlensing, extrasolar planet transits, and many other observing ... More
FRT presentation of classical Askey-Wilson algebrasJun 19 2018Automorphisms of the infinite dimensional Onsager algebra are introduced. Certain quotients of the Onsager algebra are formulated using a polynomial in these automorphisms. In the simplest case, the quotient coincides with the classical analog of the ... More
The limiting process of $N$-particle branching random walk with polynomial tailsNov 06 2013We consider a system of $N$ particles on the real line that evolves through iteration of the following steps: 1) every particle splits into two, 2) each particle jumps according to a prescribed displacement distribution supported on the positive reals ... More
On Dynamics in Selfish Network CreationDec 19 2012May 28 2013We consider the dynamic behavior of several variants of the Network Creation Game, introduced by Fabrikant et al. [PODC'03]. Equilibrium networks in these models have desirable properties like low social cost and small diameter, which makes them attractive ... More
On well-posedness of parabolic equations of Navier-Stokes type with BMO^{-1}(\R^n) dataDec 29 2014Apr 14 2015We develop a strategy making extensive use of tent spaces to study parabolic equa-tions with quadratic nonlinearities as for the Navier-Stokes system. We begin with a new proof of the well-known result of Koch and Tataru on the well-posedness of Navier-Stokes ... More