Results for "Marc Hon"

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Deep Learning Classification in Asteroseismology Using an Improved Neural Network: Results on 15000 Kepler Red Giants and Applications to K2 and TESS DataFeb 20 2018Deep learning in the form of 1D convolutional neural networks have previously been shown to be capable of efficiently classifying the evolutionary state of oscillating red giants into red giant branch stars and helium-core burning stars by recognizing ... More
K-theory of weight varietiesOct 19 2013Let $T$ be a compact torus and $(M,\omega)$ a Hamiltonian $T$-space. We give a new proof of the $K$-theoretic analogue of the Kirwan surjectivity theorem in symplectic geometry by using the equivariant version of the Kirwan map introduced in one of R. ... More
Detecting Solar-like Oscillations in Red Giants with Deep LearningApr 20 2018Time-resolved photometry of tens of thousands of red giant stars from space missions like Kepler and K2 has created the need for automated asteroseismic analysis methods. The first and most fundamental step in such analysis, is to identify which stars ... More
Mass and Age of Red Giant Branch Stars Observed with LAMOST and \emph{Kepler}Dec 28 2017Obtaining accurate and precise masses and ages for large numbers of giant stars is of great importance for unraveling the assemblage history of the Galaxy. In this paper, we estimate masses and ages of 6940 red giant branch (RGB) stars with asteroseismic ... More
Linked and knotted chimera filaments in oscillatory systemsSep 08 2015Jul 17 2016While the existence of stable knotted and linked vortex lines has been established in many experimental and theoretical systems, their existence in oscillatory systems and systems with nonlocal coupling has remained elusive. Here, we present strong numerical ... More
Asteroseismology of 16000 Kepler red giants: Global oscillation parameters, Masses, and radiiFeb 13 2018The Kepler mission has provided exquisite data to perform an ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize solar-like oscillations and granulation for 16,094 oscillating red giants, using end-of-mission ... More
Asteroseismology of 16000 Kepler Red Giants: Global Oscillation Parameters, Masses, and RadiiFeb 13 2018Apr 03 2018The Kepler mission has provided exquisite data to perform an ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize solar-like oscillations and granulation for 16,094 oscillating red giants, using end-of-mission ... More
Optimal preconditioners for systems defined by functions of Toeplitz matricesFeb 10 2018We propose several circulant preconditioners for systems defined by some functions $g$ of Toeplitz matrices $A_n$. In this paper we are interested in solving $g(A_n)\mathbf{x}=\mathbf{b}$ by the preconditioned conjugate method or the preconditioned minimal ... More
An In-place Framework for Exact and Approximate Shortest Unique Substring QueriesDec 01 2015We revisit the exact shortest unique substring (SUS) finding problem, and propose its approximate version where mismatches are allowed, due to its applications in subfields such as computational biology. We design a generic in-place framework that fits ... More
Towards an Optimal Space-and-Query-Time Index for Top-k Document RetrievalAug 02 2011Mar 30 2012Let $\D = $$ \{d_1,d_2,...d_D\}$ be a given set of $D$ string documents of total length $n$, our task is to index $\D$, such that the $k$ most relevant documents for an online query pattern $P$ of length $p$ can be retrieved efficiently. We propose an ... 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
Determinants containing powers of polynomial sequencesJun 27 2018We derive identities for the determinants of matrices whose entries are (rising) powers of (products of) polynomials that satisfy a recurrence relation. In particular, these results cover the cases for Fibonacci polynomials, Lucas polynomials and certain ... More
Data Acquisition System for Segmented Reactor Antineutrino DetectorMay 11 2016May 18 2016This paper describes the data acquisition system used for data readout from a segmented detector of reactor antineutrinos with active shielding. Theoretical approach to the data acquisition is described and two possible solutions using QDCs and digitizers ... More
Claudius Ptolemy and Giambattista Della Porta: Two Contrasting Conceptions of OpticsFeb 10 2019We address the phenomenon of reflection in concave spherical mirror in two contrasting approaches to optics. In his Optics (ca.165) Ptolemy applied the cathetus principle as a regulative means for explaining qualitatively effects related to visual perception ... More
Witten-Helffer-Sjostrand Theory for a Generalized Morse FunctionsMar 14 1995In this paper, we extend the Witten-Helffer-Sj\"{o}strand theory from Morse functions to generalized Morse functions. In this case, the spectrum of the Witten deformed Laplacian $\Delta(t)$, for large t, can be seperated into the small eigenvalues (which ... More
Equivariant structure constants for Hamiltonian-$T$-spacesSep 28 2016If there exists a set of canonical classes on a compact Hamiltonian-$T$-spaces in the sense of Goldin and Tolman, we derive some formulas for certain equivariant structure constants in terms of other equivariant structure constants and the values of canonical ... More
The Replicator Equation as an Inference DynamicNov 09 2009May 03 2010The replicator equation is interpreted as a continuous inference equation and a formal similarity between the discrete replicator equation and Bayesian inference is described. Further connections between inference and the replicator equation are given ... More
Counting cosets of unimodular groups over Dedekind domainsJan 19 2011In this paper, a formula for the calculation of the number of right cosets contained in a double coset with respect to a unimodular group over a Dedekind domain is developed, and applications of this formula in the theory of congruence subgroups -- an ... More
Automorphisms of the doubles of purely non-abelian finite groupsNov 04 2013Jun 08 2014Using a recent classification of $\operatorname{End}(\mathcal{D}(G))$, we determine a number of properties for $\operatorname{Aut}(\mathcal{D}(G))$, where $\mathcal{D}(G)$ is the Drinfel'd double of a finite group $G$. Furthermore, we completely describe ... More
The Heegaard genus of amalgamated 3-manifoldsJun 23 2003Let M and M' be simple 3-manifolds, each with connected boundary of genus at least two. Suppose that M and M' are glued via a homeomorphism between their boundaries. Then we show that, provided the gluing homeomorphism is `sufficiently complicated', the ... 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
How to extract data from proprietary software database systems using TCP/IP?Apr 26 2014May 11 2014This document is an white paper about how to connect reverse engineering and programing skills to extract data from a proprietary implementation of a database system to build EML-Tools for data format conversion into raw data. This article shows how to ... More
Equivariant classifying spaces and cdh descent for the homotopy K-theory of tame stacksApr 21 2016We construct geometric models for classifying spaces of linear algebraic groups in G-equivariant motivic homotopy theory, where G is a tame group scheme. As a consequence, we show that the equivariant motivic spectrum representing the homotopy K-theory ... 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
Information Geometry and Evolutionary Game TheoryNov 09 2009The Shahshahani geometry of evolutionary game theory is realized as the information geometry of the simplex, deriving from the Fisher information metric of the manifold of categorical probability distributions. Some essential concepts in evolutionary ... 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
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
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
On the origin of Hilbert GeometryJul 08 2014In this brief essay we succinctly comment on the historical origin of Hilbert geometry. In particular, we give a summary of the letter in which David Hilbert informs his friend and colleague Felix Klein about his discovery of this geometry. The present ... More
Discussion of "Second order topological sensitivity analysis" by J. Rocha de Faria et alAug 28 2007The article by J. Rocha de Faria et al. under discussion is concerned with the evaluation of the perturbation undergone by the potential energy of a domain $\Omega$ (in a 2-D, scalar Laplace equation setting) when a disk $B_{\epsilon}$ of small radius ... 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
Random systems and replica field theoryMar 09 1995Contents: I. Introduction II. Manifolds in random media III. Thermal fluctuations without disorder IV. Random forces V. Random potential: variational approach VI. Physical interpretation of the solution
Odd Character Degrees for Sp(2n,2)Feb 25 2011We check McKay conjecture on character degrees for the case of symplectic groups over the field with two elements Sp(2n,2) and the prime 2. Then we check the inductive McKay condition (Isaacs-Malle-Navarro 2007) for Sp(4,2^m) and all primes.
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.
Causal Field Equations and Real Eigenvalues from a Non-Local LagrangianSep 16 2003Recently, we proposed a non-local relativistic formulation of MOND (Modified Newtonian Dynamics). The equations of motion were not derived, rather they were inferred from the result one would obtain by using the Schwinger-Keldysh formalism. The formalism ... More
Fermionic fields in the pseudoparticle approachAug 17 2007The pseudoparticle approach is a numerical method to compute path integrals without discretizing spacetime. The basic idea is to consider only those field configurations, which can be represented as a linear superposition of a small number of localized ... More
Elastic models of the fast traps of carnivorous Dionaea and AldrovandaSep 04 2013The carnivorous aquatic Waterwheel Plant (Aldrovanda vesiculosa L.) and the closely related terrestrial Venus Flytrap (Dionaea muscipula SOL. EX J. ELLIS) both feature elaborate snap-traps, which shut after reception of an external mechanical stimulus ... More
Convex KKM maps, monotone operators and Minty variational inequalitiesMar 21 2015It is known that for convex sets, the KKM condition is equivalent to the finite intersection property. We use this equivalence to obtain a characterisation of monotone operators in terms of convex KKM maps and in terms of the existence of solutions to ... More
MALL proof equivalence is Logspace-complete, via binary decision diagramsFeb 06 2015Apr 17 2015Proof equivalence in a logic is the problem of deciding whether two proofs are equivalent modulo a set of permutation of rules that reflects the commutative conversions of its cut-elimination procedure. As such, it is related to the question of proofnets: ... More
Equilibration of complexes of DNA and H-NS proteins on charged surfaces: A coarse-grained model point of viewSep 22 2014The Histone-like Nucleoid Structuring protein (H-NS) is a nucleoid-associated protein, which is involved in both gene regulation and DNA compaction. Although it is a key player in genome organization by forming bridges between DNA duplexes, the precise ... More
On Pasch's Axiom and Desargues' Theorem in Busemann's workOct 25 2016In this note, we discuss the role played by the techniques from the "foundations of geometry" and in particular by Desargues' Theorem in the work of Busemann. This note is part of a forthcoming edition of Busemann's collected papers.
Large groups, Property (tau) and the homology growth of subgroupsSep 02 2005Dec 01 2005We investigate the homology of finite index subgroups G_i of a given finitely presented group G. Specifically, we examine d_p(G_i), which is the dimension of the first homology of G_i, with mod p coefficients. We say that a collection of finite index ... More
The crossing number of satellite knotsJun 15 2011Jan 25 2012We show that the crossing number of a satellite knot is at least 10^{-13} times the crossing number of its companion knot.
A polynomial upper bound on Reidemeister movesFeb 01 2013Dec 11 2014We prove that any diagram of the unknot with c crossings may be reduced to the trivial diagram using at most (236 c)^{11} Reidemeister moves. Moreover, every diagram in this sequence has at most (7 c)^2 crossings. We also prove a similar theorem for split ... More
Chow's moving lemma and the homotopy coniveau towerOct 10 2005We consider the "homotopy coniveau tower" for an arbitrary cohomology theory on smooth varieties over a field or a Dedekind domain. This tower is a generalization of the construction used by Bloch-Lichtenbaum and Friedlander-Suslin in their studies of ... 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
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
Cohomology of projective schemes: From annihilators to vanishingSep 25 2002We provide bounds on the Castelnuovo-Mumford regularity in terms of ``defining equations'' by using elements that annihilates some cohomology modules, inspired by works of Miyazaki, Nagel, Schenzel and Vogel. The elements in these annihilators are provided ... More
Projective schemes: What is Computable in low degree?Oct 30 2002This article first presents two examples of algorithms that extracts information on scheme out of its defining equations. We also give a review on the notion of Castelnuovo-Mumford regularity, its main properties (in particular its relation to computational ... More
Nonexistence of spacelike foliations and the dominant energy condition in Lorentzian geometryFeb 12 2007We show that many Lorentzian manifolds of dimension >2 do not admit a spacelike codimension-one foliation, and that almost every manifold of dimension >2 which admits a Lorentzian metric at all admits one which satisfies the dominant energy condition ... More
Convergence of Voevodsky's slice towerDec 31 2011Mar 07 2013We consider Voevodsky's slice tower for a finite spectrum E in the motivic stable homotopy category over a perfect field k. In case k has finite cohomological dimension (in characteristic two, we also require that k is infinite), we show that the slice ... More
Slow dynamics for the dilute Ising model in the phase coexistence regionJun 13 2012In this paper we consider the Glauber dynamics for a disordered ferromagnetic Ising model, in the region of phase coexistence. It was conjectured several decades ago that the spin autocorrelation decays as a negative power of time [Huse and Fisher, Phys. ... More
The Adams-Novikov spectral sequence and Voevodsky's slice towerNov 17 2013Oct 03 2015We show that the spectral sequence converging to the stable homotopy groups of spheres, induced by the Betti realization of the slice tower for the motivic sphere spectrum, agrees with the Adams-Novikov spectral sequence, after a suitable re-indexing. ... More
The étale symmetric Künneth theoremSep 30 2018Oct 08 2018Let $k$ be an algebraically closed field, $l\neq\operatorname{char} k$ a prime number, and $X$ a quasi-projective scheme over $k$. We show that the \'etale homotopy type of the $d$th symmetric power of $X$ is $\mathbb Z/l$-homologically equivalent to ... More
Generalized Fitch Graphs: Edge-labeled Graphs that are explained by Edge-labeled TreesFeb 10 2018Apr 25 2018Fitch graphs $G=(X,E)$ are di-graphs that are explained by $\{\otimes,1\}$-edge-labeled rooted trees with leaf set $X$: there is an arc $xy\in E$ if and only if the unique path in $T$ that connects the least common ancestor $\textrm{lca}(x,y)$ of $x$ ... More
Toward an algebraic theory of Welschinger invariantsAug 07 2018Let $S$ be a smooth del Pezzo surface over a field $k$ of characteristic $\neq 2, 3$. We define an invariant in the Grothendieck-Witt ring $GW(k)$ for "counting" rational curves in a curve class $D$ of fixed positive degree (with respect to the anti-canonical ... More
Momentum-space conformal blocks on the light coneJul 18 2018Oct 17 2018We study the momentum-space 4-point correlation function of identical scalar operators in conformal field theory. Working specifically with null momenta, we show that its imaginary part admits an expansion in conformal blocks. The blocks are polynomials ... More
Liaison of varieties of small dimension and deficiency modulesOct 29 2002Sep 11 2003This article studies the behaviour under liaison of the deficiency modules of schemes that are not assumed to be Cohen-Macaulay. Our study uses in particular a generalization of Serre duality, and gives a satisfactory description of this behaviour in ... More
The canonical Cartan bundle and connection in CR geometryMay 02 2006May 29 2006We give a differential geometric description of the Cartan (or tractor) bundle and its canonical connection in CR geometry, thus offering a direct, alternative, definition to the usual abstract approach.
A family of non-FSZ finite symplectic groupsJan 31 2019Let $p$ be an odd prime with $p\equiv1\bmod 4$. Then for any odd power $q$ of $p$ and a positive integer $j$ we show that the groups $\text{Sp}_{p^j+1}(q),\text{PSp}_{p^j+1}(q)$, and their Sylow $p$-subgroups are non-$FSZ_{p^j}$.
A differentiation theorem for uniform measuresAug 15 2013Using the notion of higher-order Fourier dimension introduced in \cite{M2} (which was a sort of psuedorandomness condition stemming from the Gowers norms of Additive Combinatorics), we prove a maximal theorem and corresponding differentiation theorem ... More
A Note on the Space Complexity of Fast D-Finite Function EvaluationSep 23 2012We state and analyze a generalization of the "truncation trick" suggested by Gourdon and Sebah to improve the performance of power series evaluation by binary splitting. It follows from our analysis that the values of D-finite functions (i.e., functions ... More
Overview on All Reactions Linked to GPDsJul 14 2002A short overview is given on how generalized parton distributions (GPDs) enter in a variety of hard exclusive processes such as deeply virtual Compton scattering (DVCS) and hard meson electroproduction reactions on the nucleon. We firstly discuss the ... More
Real and Virtual Compton Scattering off the NucleonJul 21 2000A review is given of the very recent developments in the fields of real and virtual Compton scattering off the nucleon. Both real and virtual Compton scattering reactions are discussed at low outgoing photon energy where one accesses polarizabilities ... More
Comment on: 'Universal Behavior of Load Distribution in Scale-free Networks'Apr 14 2003Oct 29 2003In a previous Letter (cond-mat/0106565), Goh et al have presented a numerical study of the load--or betweenness centrality--distribution in a scale-free network whose degree distribution follows a power law with a tunable exponent $\gamma$. They showed ... More
Path Integral Approach to Strongly Nonlinear CompositeMay 29 2000We study strongly nonlinear disordered media using a functional method. We solve exactly the problem of a nonlinear impurity in a linear host and we obtain a Bruggeman-like formula for the effective nonlinear susceptibility. This formula reduces to the ... More
Chiral perturbation theory confronted with experimentSep 08 2004Oct 12 2004The general framework and the present status of the low energy theory of the standard model are briefly reviewed. Recent applications to a few topic of interest for the determinations of Vud and of Vus are discussed
A coarse graining for the Fortuin-Kasteleyn measure in random mediaMay 11 2007Dec 18 2007By means of a multi-scale analysis we describe the typical geometrical structure of the clusters under the FK measure in random media. Our result holds in any dimension greater or equal to 2 provided that slab percolation occurs under the averaged measure, ... More
The Python user interface of the elsA CFD software: a coupling framework for external steering layersJul 22 2016Jul 27 2016The Python--elsA user interface of the elsA CFD (Computational Fluid Dynamics) software has been developed to allow users to specify simulations with confidence, through a global context of description objects grouped inside scripts. The software main ... More
Charged Leptons With Nanosecond LifetimesApr 07 1995Some extensions of the standard model contain additional leptons which are vectorlike under weak isospin. A class of models is considered in which these leptons do not appreciably mix with the known leptons. In such models, the heavy charged lepton and ... More
A family of criteria for irrationality of Euler's constantJul 12 2005Following earlier results of Sondow, we propose another criterion of irrationality for Euler's constant $\gamma$. It involves similar linear combinations of logarithm numbers $L\_{n,m}$. To prove that $\gamma$ is irrational, it suffices to prove that, ... More
Isotropic realizability of electric fields around critical pointsJun 02 2013In this paper we study the isotropic realizability of a given regular gradient field $\nabla u$ as an electric field, namely when $\nabla u$ is solution of the equation $\div\left(\si\nabla u\right)=0$ for some isotropic conductivity $\si>0$. The case ... More
Spectral geometry, link complements and surgery diagramsOct 29 2008We provide an upper bound on the Cheeger constant and first eigenvalue of the Laplacian of a finite-volume hyperbolic 3-manifold M, in terms of data from any surgery diagram for M. This has several consequences. We prove that a family of hyperbolic alternating ... More
Some 3-manifolds and 3-orbifolds with large fundamental groupJul 14 2005We provide two new proofs of a theorem of Cooper, Long and Reid which asserts that, apart from an explicit finite list of exceptional manifolds, any compact orientable irreducible 3-manifold with non-empty boundary has large fundamental group. The first ... More
Taut ideal triangulations of 3-manifoldsMar 22 2000Nov 10 2000A taut ideal triangulation of a 3-manifold is a topological ideal triangulation with extra combinatorial structure: a choice of transverse orientation on each ideal 2-simplex, satisfying two simple conditions. The aim of this paper is to demonstrate that ... More
Word hyperbolic Dehn surgeryAug 28 1998Sep 07 1999The aim of this paper is to demonstrate that very many Dehn fillings on a cusped hyperbolic 3-manifold yield a 3-manifold which is irreducible, atoroidal and not Seifert fibred, and which has infinite, word hyperbolic fundamental group. We establish an ... More
Core curves of triangulated solid toriJun 15 2011We show that in any triangulation of a solid torus, there is a pre-core curve that lies in the 2-skeleton and that intersects the interior of each face in at most 10 straight arcs. By definition, a pre-core curve is a simple closed curve that becomes ... More
An algorithm to determine the Heegaard genus of simple 3-manifolds with non-empty boundarySep 04 2007Jan 24 2008We provide an algorithm to determine the Heegaard genus of simple 3-manifolds with non-empty boundary. More generally, we supply an algorithm to determine (up to ambient isotopy) all the Heegaard splittings of any given genus for the manifold. As a consequence, ... More
Exceptional surgery curves in triangulated 3-manifoldsJul 14 1999For the purposes of this paper, Dehn surgery along a curve K in a 3-manifold M with slope r is `exceptional' if the resulting 3-manifold M_K(r) is reducible or a solid torus, or the core of the surgery solid torus has finite order in the fundamental group ... More
An Approximation Algorithm for #k-SATJul 11 2011We present a simple randomized algorithm that approximates the number of satisfying assignments of Boolean formulas in conjunctive normal form. To the best of our knowledge this is the first algorithm which approximates #k-SAT for any k >= 3 within a ... More
3+1 description of silent universes: a uniqueness result for the Petrov type I vacuum caseSep 29 1999Silent universes are studied using a ``3+1'' decomposition of the field equations in order to make progress in proving a recent conjecture that the only silent universes of Petrov type I are spatially homogeneous Bianchi I models. The infinite set of ... More
New lower bounds on subgroup growth and homology growthDec 13 2005May 27 2008We establish new strong lower bounds on the (subnormal) subgroup growth of a large class of groups. This includes the fundamental groups of all finite-volume hyperbolic 3-manifolds and all (free non-abelian)-by-cyclic groups. The lower bound is nearly ... More
Compaction of bacterial genomic DNA: Clarifying the conceptsSep 08 2015The unconstrained genomic DNA of bacteria forms a coil, which volume exceeds 1000 times the volume of the cell. Since prokaryotes lack a membrane-bound nucleus, in sharp contrast with eukaryotes, the DNA may consequently be expected to occupy the whole ... More
Universal Approximation of Edge Density in Large GraphsAug 06 2015In this paper, we present a novel way to summarize the structure of large graphs, based on non-parametric estimation of edge density in directed multigraphs. Following coclustering approach, we use a clustering of the vertices, with a piecewise constant ... More
Counting matchings in irregular bipartite graphs and random liftsJul 16 2015Nov 05 2015We give a sharp lower bound on the number of matchings of a given size in a bipartite graph. When specialized to regular bipartite graphs, our results imply Friedland's Lower Matching Conjecture and Schrijver's theorem proven by Gurvits and Csikvari. ... More
There are no finite partial cubes of girth more than 6 and minimum degree at least 3Mar 16 2015Jul 21 2016Partial cubes are graphs isometrically embeddable into hypercubes. We analyze how isometric cycles in partial cubes behave and derive that every partial cube of girth more than 6 must have vertices of degree less than 3. As a direct corollary we get that ... More
The Python user interface of the elsA cfd software: a coupling framework for external steering layersJul 22 2016Nov 18 2016The Python--elsA user interface of the elsA cfd (Computational Fluid Dynamics) software has been developed to allow users to specify simulations with confidence, through a global context of description objects grouped inside scripts. The software main ... More
On Banachic Kernels and Approximation TheoryJun 25 2016In this paper, I generalize a previous one about hilbertian kernels and approximation theory
The $C^0$ integrability of symplectic twist maps without conjugate pointsJun 09 2016We prove that symplectic twist maps defined on the cotangent bundle of the d-dimensional torus that have no conjugate points are $C^0$ integrable, i.e. the cotangent bundle is continuously foliated by a family of invariant Lagrangian graphs.