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
Optimization of Structural Flood Mitigation StrategiesMar 01 2018Apr 02 2019The dynamics of flooding are primarily influenced by the shape, height, and roughness (friction) of the underlying topography. For this reason, mechanisms to mitigate floods frequently employ structural measures that either modify topographic elevation, ... 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
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
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
The Commute Trip Sharing ProblemApr 24 2019Parking pressure has been steadily increasing in cities as well as in university and corporate campuses. To relieve this pressure, this paper studies a car-pooling platform that would match riders and drivers, while guaranteeing a ride back and exploiting ... More
Modeling Stated Preference for Mobility-on-Demand Transit: A Comparison of Machine Learning and Logit ModelsNov 04 2018Apr 01 2019Logit 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
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
Graphical Models and Belief Propagation-hierarchy for Optimal Physics-Constrained Network FlowsFeb 07 2017In this manuscript we review new ideas and first results on application of the Graphical Models approach, originated from Statistical Physics, Information Theory, Computer Science and Machine Learning, to optimization problems of network flow type with ... 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
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
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
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
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
OptStream: Releasing Time Series PrivatelyAug 06 2018Oct 30 2018Many applications of machine learning and optimization operate on data streams. While these datasets are fundamental to fuel decision-making algorithms, often they contain sensitive information about individuals and their usage poses significant privacy ... 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
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
Assortment and Price Optimization Under the Two-Stage Luce modelJun 26 2017Apr 23 2019This paper studies assortment and pricing optimization problems under the Two-Stage Luce model (2SLM), a discrete choice model introduced by Echenique and Saito (2018) that generalizes the multinomial logit model (MNL). The model employs an utility function ... More
Optimization of Topography-based Flood Mitigation StrategiesMar 01 2018The dynamics of flooding are primarily influenced by the shape and height of the underlying topography. For this reason, mechanisms to mitigate floods frequently employ structures that increase topographic elevation, e.g., levees and sandbags. However, ... 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
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
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
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
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
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
Assortment Optimization under the General Luce ModelJun 26 2017This paper studies the assortment optimization problem under the General Luce Model (GLM), a discrete choice introduced by Echenique and Saito (2015) that generalizes the standard multinomial logit model (MNL). The GLM does not satisfy the Independence ... 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
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
Assortment Optimization under the Sequential Multinomial Logit ModelJul 09 2017Aug 30 2018We study the assortment optimization problem under the Sequential Multinomial Logit (SML), a discrete choice model that generalizes the multinomial logit (MNL). Under the SML model, products are partitioned into two levels, to capture differences in attractiveness, ... 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
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
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
Privacy-Preserving Obfuscation of Critical Infrastructure NetworksMay 23 2019The paper studies how to release data about a critical infrastructure network (e.g., the power network or a transportation network) without disclosing sensitive information that can be exploited by malevolent agents, while preserving the realism of the ... 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
DistFlow Extensions for AC Transmission SystemsMay 27 2015Jul 02 2018Convex 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
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
Phase Transitions for Optimality Gaps in Optimal Power Flows A Study on the French Transmission NetworkJul 14 2018This paper investigates phase transitions on the optimality gaps in Optimal Power Flow (OPF) problem on real-world power transmission systems operated in France. The experimental results study optimal power flow solutions for more than 6000 scenarios ... 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
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
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
Privacy-Preserving Obfuscation of Critical Infrastructure NetworksMay 23 2019May 24 2019The paper studies how to release data about a critical infrastructure network (e.g., the power network or a transportation network) without disclosing sensitive information that can be exploited by malevolent agents, while preserving the realism of the ... 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
Constraint and Mathematical Programming Models for Integrated Port Container Terminal OperationsDec 14 2017This paper considers the integrated problem of quay crane assignment, quay crane scheduling, yard location assignment, and vehicle dispatching operations at a container terminal. The main objective is to minimize vessel turnover times and maximize the ... 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
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
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
Differential Privacy for Power Grid ObfuscationJan 21 2019May 22 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
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
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
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
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
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
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
Resilient Transmission Grid Design: AC Relaxation vs. DC approximationMar 17 2017As illustrated in recent years (Superstorm Sandy, the Northeast Ice Storm of 1998, etc.), extreme weather events pose an enormous threat to the electric power transmission systems and the associated socio-economic systems that depend on reliable delivery ... 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
A quantum magnetic RC circuitJan 22 2014We propose a setup that is the spin analog of the charge-based quantum RC circuit. We define and compute the spin capacitance and the spin resistance of the circuit for both ferromagnetic (FM) and antiferromagnetic (AF) systems. We find that the antiferromagnetic ... 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
A Lyra2 FPGA Core for Lyra2REv2-Based CryptocurrenciesJul 16 2018Feb 17 2019Lyra2REv2 is a hashing algorithm that consists of a chain of individual hashing algorithms and it is used as a proof-of-work function in several cryptocurrencies that aim to be ASIC-resistant. The most crucial hashing algorithm in the Lyra2REv2 chain ... More
Tunneling spectroscopy of localized states of $\mathrm{WS}_2$ barriers in vertical van der Waals heterostructuresJun 25 2019In transition metal dichalcogenides, defects have been found to play an important role, affecting doping, spin-valley relaxation dynamics, and assisting in proximity effects of spin-orbit coupling. Here, we study localized states in $\mathrm{WS}_2$ and ... 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
Equivariant Cohomology and Localization Formula in SupergeometryFeb 04 2004Let G be a compact Lie group. Let M be a smooth G-manifold and V --> M be an oriented G-equivariant vector bundle. One defines the spaces of equivariant forms with generalized coefficients on V and M. An equivariant Thom form $\theta$ on V is a compactly ... More
La cohomologie des espaces de Lubin-Tate est libreSep 08 2013Aug 31 2018This article is the entire version, that is with coefficients in the ring of integers of a local field, of my last paper at inventiones. The principal result is the freeness of the cohomology groups of the Lubin-Tate tower. The strategy is to study the ... More
Filtrations de stratification de quelques variétés de Shimura simplesSep 08 2013Dec 22 2014We define and study new filtrations called of stratification of a perverse sheaf on a scheme; beside the cases of the weight or monodromy filtrations, these filtrations are available whatever are the ring of coefficients. We illustrate these constructions ... More
Faisceaux pervers des cycles évanescents des variétés de Drinfeld et groupes de cohomologie du modèle de Deligne-CarayolFeb 06 2006In the first half of the paper, we translate in the geometric situation of Drinfeld varieties, the principal results of the Harris and Taylor's book. We give in particular the restriction to the open strata of the vanishing cycles sheaves in terms of ... More
Coupling in the queue with impatience: case of several serversNov 08 2017Nov 17 2017We present the explicit construction of a stable queue with several servers and impatient customers, under stationary ergodic assumptions. Using a stochastic comparison of the (multivariate) workload sequence with two monotonic stochastic recursions, ... 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
Local $\mathbb F_l$-monodromy and level fixingAug 19 2019We tackle three related problems. The first deals with freeness of localized cohomology groups of Harris-Taylor perverse sheaves, defined on the special fiber of some Kottwitz-Harris-Taylor Shimura variety. We then study the nilpotent monodromy operator ... More
Efficient heating of single-molecule junctions for thermoelectric studies at cryogenic temperaturesJul 05 2019The energy dependent thermoelectric response of a single molecule contains valuable information about its transmission function and its excited states. However, measuring it requires devices that can efficiently heat up one side of the molecule while ... 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
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.
A polynomial-time randomized reduction from tournament isomorphism to tournament asymmetryApr 27 2017The paper develops a new technique to extract a characteristic subset from a random source that repeatedly samples from a set of elements. Here a characteristic subset is a set that when containing an element contains all elements that have the same probability. ... More
Two impurities in a Bose-Einstein condensate: from Yukawa to Efimov attracted polaronsJul 15 2016Apr 13 2018The well-known Yukawa and Efimov potentials are two different mediated interaction potentials. The first one arises in quantum field theory from the exchange of virtual particles. The second one is mediated by a real particle resonantly interacting with ... More
Simple Necessary Conditions for the Existence of a Hamiltonian Path with Applications to Cactus GraphsSep 05 2017We describe some necessary conditions for the existence of a Hamiltonian path in any graph (in other words, for a graph to be traceable). These conditions result in a linear time algorithm to decide the Hamiltonian path problem for cactus graphs. We apply ... More
The third law of thermodynamics or an absolute definition for Entropy. Part 1 : the origin and applications in thermodynamicsApr 26 2019May 29 2019This article describes the third law of thermodynamics. This law is often poorly known and is often decried, or even considered optional and irrelevant to describe weather and climate phenomena. This, however, is inaccurate and contrary to scientific ... More
About Galois reducibility of torsion cohomology classes for KHT Shimura varietiesMar 26 2019Jul 03 2019We pursue the original strategy of my paper at JIMJ and we give a new criterion so that the localization of the cohomology of KHT Shimura variety is free. Precisely let $G$ be a similitude group with signatures $(1,d-1),(0,d),\cdots,(0,d)$ and $V_{\xi,\overline{\mathbb ... More
Comment on the paper "Generalized dynamic equations related to condensation and freezing processes" by Wang and Huang (2018)Jan 25 2019Jan 28 2019The condensation Probability Function defined in papers of X.R. Wang is criticized on many aspects. The modified latent heat and potential temperature are plotted and compared to usual atmospheric formulations.
Doubled patterns are $3$-avoidableOct 06 2015In combinatorics on words, a word $w$ over an alphabet $\Sigma$ is said to avoid a pattern $p$ over an alphabet $\Delta$ if there is no factor $f$ of $w$ such that $f=h(p)$ where $h:\Delta^*\to\Sigma^*$ is a non-erasing morphism. A pattern $p$ is said ... More
Monodromy of the perverse sheaf of vanishing cycles of some simple Shimura varieties and applicationsNov 21 2005Feb 06 2006In the geometric situation of the simple Shimura varieties of Kottwitz studied in Harris and Taylor's book, we describe the monodromy filtration of the vanishing cycles complex and the spectral sequence associated to it. We prove in particular that this ... More
On necessary and sufficient conditions for $L^p$-estimates of Riesz transforms associated to elliptic operators on $\RR^n$ and related estimatesJun 02 2005Jun 06 2005This article focuses on $L^p$ estimates for objects associated to elliptic operators in divergence form: its semigroup, the gradient of the semigroup, functional calculus, square functions and Riesz transforms. We introduce four critical numbers associated ... More
SuperpfaffianFeb 04 2004Let V=V_0+V_1 be a real finite dimensional supervector space provided with a non-degenerate antisymmetric even bilinear form B. Let spo(V) be the Lie superalgebra of endomorphisms of V which preserve B. We consider spo(V) as a supermanifold. We show that ... More
A factorisation theorem for curve with vanishing self-intersectionMay 14 2014Jun 20 2014Let C be a curve in a compact Kahler surface Y. Assume that the self-intersection of C is vanishing, and the image of the fundamental group of C in Y is of infinite index in the fundamental group of Y. Does it follow that C is a fiber of a holomorphic ... More
Rectification effect in organic junctions based on aryl thin films covalently attached to a multilayer graphene electrodeMay 04 2018The quantum interaction between molecules and electrode s material at molecules-electrode interfaces is a major ingredient in the electronic transport properties of organic junctions. Driven by the coupling strength between the two materials, it results ... More
Ground-state spin blockade in a single-molecule junctionDec 17 2018It is known that the quantum-mechanical ground state of a nano-scale junction has a significant impact on its electrical transport properties. This becomes particularly important in transistors consisting of a single molecule. Due to strong electron-electron ... 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
A local form for the automorphisms of the spectral unit ballJan 22 2008If F is an automorphism of the spectral unit ball, we show that, in a neighborhood of any cyclic (i.e. non-derogatory) matrix of the ball, the map F can be written as conjugation by a holomorphically varying non singular matrix. This provides a shorter ... More
Relative second bounded cohomology of free groupsJul 15 2014Mar 30 2015This paper is devoted to the computation of the space $H_b^2(\Gamma,H;\mathbb{R})$, where $\Gamma$ is a free group of finite rank $n\geq 2$ and $H$ is a subgroup of finite rank. More precisely we prove that $H$ has infinite index in $\Gamma$ if and only ... More