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
Deep Learning Classification in AsteroseismologyMay 18 2017Jun 17 2017In the power spectra of oscillating red giants, there are visually distinct features defining stars ascending the red giant branch from those that have commenced helium core burning. We train a one-dimensional convolutional neural network by supervised ... 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
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
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
A note on congruence properties of the generalized bi-periodic Horadam sequenceMar 01 2019In this paper, we consider a generalization of Horadam sequence {w_n} which is defined by the recurrence w_n = aw_n-1 + cw_n-2; if n is even, w_n = bw_n-1 + cw_n-2; if n is odd with arbitrary initial conditions w_0, w_1 and nonzero real numbers a, b, ... 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
A Search for Red Giant Solar-like Oscillations in All Kepler DataMar 01 2019Mar 04 2019The recently published Kepler mission Data Release 25 (DR25) reported on ~197,000 targets observed during the mission. Despite this, no wide search for red giants showing solar-like oscillations have been made across all stars observed in Kepler's long-cadence ... More
Asteroseismology of the Hyades red giant and planet host epsilon TauriJan 18 2019Feb 22 2019Asteroseismic analysis of solar-like stars allows us to determine physical parameters such as stellar mass, with a higher precision compared to most other methods. Even in a well-studied cluster such as the Hyades, the masses of the red giant stars are ... More
The TESS-HERMES survey Data Release 1: high-resolution spectroscopy of the TESS southern continuous viewing zoneJul 18 2017Sep 30 2017The Transiting Exoplanet Survey Satellite (TESS) will provide high precision time-series photometry for millions of stars with at least a half-hour cadence. Of particular interest are the circular regions of 12-degree radius centered around the ecliptic ... More
Circulant preconditioners for functions of Hermitian Toeplitz matricesJul 28 2018Circulant preconditioners for functions of matrices have been recently of interest. In particular, several authors proposed the use of the optimal circulant preconditioners as well as the superoptimal circulant preconditioners in this context and numerically ... More
The K2-HERMES Survey. I. Planet Candidate Properties from K2 Campaigns 1-3Dec 19 2017Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present first results from the ... 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
Cavity-induced emergent topological spin textures in a Bose Einstein condensateJul 09 2018The coupled nonlinear dynamics of ultracold quantum matter and electromagnetic field modes in an optical resonator exhibits a wealth of intriguing collective phenomena. Here we study a $\Lambda$-type, three-component Bose-Einstein condensate coupled to ... More
Identifying conserved protein complexes between species by constructing interolog networksJul 15 2013Protein complexes conserved across species indicate processes that are core to cellular machinery (e.g. cell-cycle or DNA damage-repair complexes conserved across human and yeast). While numerous computational methods have been devised to identify complexes ... More
Topological Color-Hall Insulators: SU(3) Fermions in Optical LatticesApr 29 2019We discuss the emergence of topological color insulators in optical lattices as quantum phases of SU(3) ultra-cold neutral fermions. We construct the Chern matrix and classify all insulating phases in terms of three topological invariants: the charge-charge, ... 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
Counting real critical points of the distance to orthogonally invariant matrix setsFeb 06 2015Jun 16 2015Minimizing the Euclidean distance to a set arises frequently in applications. When the set is algebraic, a measure of complexity of this optimization problem is its number of critical points. In this paper we provide a general framework to compute and ... 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
The K2-HERMES Survey: Age and Metallicity of the Thick DiscApr 29 2019Asteroseismology is a promising tool to study Galactic structure and evolution because it can probe the ages of stars. Earlier attempts comparing seismic data from the {\it Kepler} satellite with predictions from Galaxy models found that the models predicted ... More
Towards Alzheimer's Disease Classification through Transfer LearningNov 29 2017Detection of Alzheimer's Disease (AD) from neuroimaging data such as MRI through machine learning have been a subject of intense research in recent years. Recent success of deep learning in computer vision have progressed such research further. However, ... More
On a generalization of the Pentagonal Number TheoremSep 02 2018We study a generalization of the classical Pentagonal Number Theorem and its applications. We derive new identities for certain infinite series, recurrence relations and convolution sums for certain restricted partitions and divisor sums. We also derive ... More
An interesting link between linear feasibility, linear programming, support vector machine and convex hullJan 22 2019May 07 2019This short paper presents an algorithm based on simple projections and linear feasibility ($Ax=\mathbf{0},\ x>\mathbf{0}$) queries which solves linear programming ($\underset{x \ / \ Ax\geq b}{\min}\ cx$), and, support vector machine ($\underset{w \ / ... More
Solving linear program with Chubanov queries and bisection movesJan 22 2019Feb 01 2019This short article focus on the link between linear feasibility and generic linear program. An algorithm is presented to solve generic linear program using linear feasibility queries and working at constraint level instead of raw values level. Even if ... 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
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
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.
Simpler, Linear-Time Transitive Orientation via Lexicographic Breadth-First SearchMar 10 2015Comparability graphs are the undirected graphs whose edges can be directed so that the resulting directed graph is transitive. They are related to posets and have applications in scheduling theory. This paper considers the problem of finding a transitive ... More
Topoi of parametrized objectsNov 07 2016We give necessary and sufficient conditions on a presentable infinity-category C so that families of objects of C form an infinity-topos. In particular, we prove a conjecture of Joyal that this is the case whenever C is stable.
DARWINNov 27 2011DARWIN is a design-study for a next-to-next generation experiment to directly detect WIMP dark matter in a detector based on a liquid xenon/liquid argon two-phase time projection chamber. This article describes the project, its goals and challenges, and ... More
The Coleman-Weinberg Phase Transition in Extended Higgs ModelsJul 16 1996In Coleman-Weinberg symmetry breaking, all dimensionful parameters vanish and the symmetry is broken by loop corrections. Before Coleman-Weinberg symmetry breaking in the Standard Model was experimentally ruled out, it had already been excluded on cosmological ... More
Universal Extra Dimensions and Kaluza-Klein Bound StatesSep 02 2004We study the bounds states of the Kaluza-Klein (KK) excitations of quarks in models of Universal Extra Dimensions. Such bound states may be detected at future lepton colliders in the cross section for the pair-production of KK-quarks near threshold. For ... More
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
Coordination in Network Security Games: a Monotone Comparative Statics ApproachAug 20 2012Malicious softwares or malwares for short have become a major security threat. While originating in criminal behavior, their impact are also influenced by the decisions of legitimate end users. Getting agents in the Internet, and in networks in general, ... More
Betweenness Centrality in Large Complex NetworksSep 18 2003May 13 2004We analyze the betweenness centrality (BC) of nodes in large complex networks. In general, the BC is increasing with connectivity as a power law with an exponent $\eta$. We find that for trees or networks with a small loop density $\eta=2$ while a larger ... More
Crossover from Scale-Free to Spatial NetworksDec 04 2002Sep 22 2003In many networks such as transportation or communication networks, distance is certainly a relevant parameter. In addition, real-world examples suggest that when long-range links are existing, they usually connect to hubs-the well connected nodes. We ... More
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
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
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
Applications of quasitriangular structures for the doubles of purely non-abelian groupsAug 22 2017We further investigate the quasitriangular structures of $\mathcal{D}(G)$ and obtain formulas for their $S$- and $T$-matrices. This is then leveraged to obtain a variety of new identities for higher Frobenius-Schur indicators and the fusion ring. We are ... 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
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
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
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
Review of AdS/CFT Integrability, Chapter II.3: Sigma Model, Gauge FixingDec 17 2010Mar 01 2011This review is devoted to the classical integrability of the AdS5xS5 superstring theory. It starts with a reminder of the corresponding action as a coset model. The symmetries of this action are then reviewed. The classical integrability is then considered ... 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
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
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.
The Legendrian knot complement problemApr 18 2016Aug 11 2018We prove that every Legendrian knot in the tight contact structure of the 3-sphere is determined by the contactomorphism type of its exterior. Moreover, by giving counterexamples we show this to be not true for Legendrian links in the tight 3-sphere. ... More
Calendrical Interpretation of Spirals in Irish Megalithic ArtFeb 11 2019The tumuli of Newgrange and Knowth in Ireland are among the most monumental heritages of the Neolithic era. The megalithic constructions date back to around 3'200 BC, centuries before the completion of Stonehenge and the Egyptian pyramids. Passageways ... More
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
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
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
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.
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
Upper semismooth functions and the subdifferential determination propertyMar 08 2017In this paper, an upper semismooth function is defined to be a lower semicontinuous function whose radial subderivative satisfies a mild directional upper semicontinuity property. Examples of upper semismooth functions are the proper lower semicontinuous ... 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
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.
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
Newton methods for k-order Markov Constrained Motion ProblemsJul 01 2014This is a documentation of a framework for robot motion optimization that aims to draw on classical constrained optimization methods. With one exception the underlying algorithms are classical ones: Gauss-Newton (with adaptive step size and damping), ... More
A new approach to the orientation of random hypergraphsJan 25 2012A h-uniform hypergraph H=(V,E) is called (l,k)-orientable if there exists an assignment of each hyperedge e to exactly l of its vertices such that no vertex is assigned more than k hyperedges. Let H_{n,m,h} be a hypergraph, drawn uniformly at random from ... More
X-rays of Stellar Coronae with Chandra and XMM-Newton: Flares and Elemental Composition in Stellar Atmospheres (Invited review)Sep 21 2004Observations of magnetically active stars with Chandra and XMM-Newton have deepened our knowledge of the physics of the atmospheres in late-type stars. In this review paper, I discuss two topics that have profited significantly from Chandra and XMM-Newton. ... More
Working group summary: pi-N sigma termDec 21 1999Several new theoretical and experimental developments concerning the determination of the nucleon sigma term are presented and discussed. Contribution to the Eighth International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon, Zuoz, ... More
Shock-in-jet model for quasars and microquasarsOct 05 2010We present the theoretical background and detailed equations for the synchrotron emission of a shock wave propagating in a relativistic jet. We then show how the evolution of an outburst in this shock-in-jet scenario can be analytically described and ... More
Review of prospects for H^+ in non-SUSY multi-Higgs models in view of LHC resultsDec 04 2012In this talk, prospects for the charged Higgs in non-SUSY models are reviewed, in view of LHC results (as of October, 2012). The four models (Type I, Type II, lepton-specific and flipped) without tree level flavor-changing neutral currents are discussed. ... More
Large Electric Dipole Moments of Heavy LeptonsMay 31 2001Jul 25 2001In many models of CP violation, the electric dipole moments (EDMs) of leptons scale as the cube of the lepton mass. In these models, the EDM of a 100 GeV heavy lepton would be a billion times greater than that of the muon, and could be as large as a 0.01 ... More
Precise Vacuum Stability Bound in the Standard Model (addendum)Apr 27 1994This is an addendum to the paper of the above title published in Physics Letters B317, 159 (1993). In that paper, I found the lower bound to the Higgs mass as a function of the top quark mass one obtains by requiring that the standard model vacuum be ... More
Long-Lived Charged Heavy LeptonsOct 18 1993Very little is known about the mass spectrum of fermions in the standard model. In this talk, I point out that in the simplest extension of the standard model, in which all right-handed fields are singlets, it is quite possible that a fourth-generation ... More
eta and eta' Physics at MAMIOct 07 2009The Crystal Ball at MAMI setup offers an excellent possibility to study decays of the eta and eta' meson. Here, recent results of the Crystal Ball at MAMI experiment from eta meson decays are presented. Furthermore, future perspectives of this experiment ... More
Perturbative theory for the Boltzmann equation in bounded domains with different boundary conditionsJul 11 2015Jul 21 2016We study the Boltzmann equation near a global Maxwellian in the case of bounded domains. We consider the boundary conditions to be either specular reflections or Maxwellian diffusion. Starting from the reference work of Guo in $L^\infty_{x,v}\left(\left(1+|v|\right)^\beta ... More
A Novel Augmented Lagrangian Approach for Inequalities and Convergent Any-Time Non-Central UpdatesDec 14 2014Motivated by robotic trajectory optimization problems we consider the Augmented Lagrangian approach to constrained optimization. We first propose an alternative augmentation of the Lagrangian to handle the inequality case (not based on slack variables) ... More
Homomorphisms and rigid isomorphisms of twisted group doublesMay 01 2016Jun 11 2016We prove several results concerning quasi-bialgebra morphisms $\mathcal{D}^\omega(G)\to\mathcal{D}^\eta(H)$ of twisted group doubles. We take a particular focus on the isomorphisms which are simultaneously isomorphisms $\mathcal{D}(G)\to\mathcal{D}(H)$. ... More
A global take on congestion in urban areasApr 13 2016May 04 2016We analyze the congestion data collected by a GPS device company (TomTom) for almost 300 urban areas in the world. Using simple scaling arguments and data fitting we show that congestion during peak hours in large cities grows essentially as the square ... More
About Gordan's algorithm for binary formsMar 04 2014Jun 19 2015In this paper, we present a modern version of Gordan's algorithm on binary forms. Symbolic method is reinterpreted in terms of $\mathsf{SL}_2(\mathbb{C})$--equivariant homomorphisms defined upon Cayley operator and polarization operator. A graphical approach ... More
Quantum attacks against iterated block ciphersOct 06 2014Apr 26 2015We study the amplification of security against quantum attacks provided by iteration of block ciphers. In the classical case, the Meet-in-the-middle attack is a generic attack against those constructions. This attack reduces the time required to break ... More
Some conditionally hard problems on links and 3-manifoldsFeb 26 2016Apr 04 2016We show that three natural decision problems about links and 3-manifolds are computationally hard, assuming some standard conjectures in complexity theory. These problems are: the problem of determining whether a link in the 3-sphere bounds a Seifert ... More
Quasitriangular structures of the double of a finite groupNov 27 2014We give a classification of all weak $R$-matrices on $\mathcal{D}(G)$, the Drinfeld double of a finite group $G$, over an arbitrary field. As an application we determine all quasitriangular structures and ribbon elements of $\mathcal{D}(G)$ explictly ... More
Localizing VolatilitiesApr 13 2006We propose two main applications of Gy\"{o}ngy (1986)'s construction of inhomogeneous Markovian stochastic differential equations that mimick the one-dimensional marginals of continuous It\^{o} processes. Firstly, we prove Dupire (1994) and Derman and ... More
Colourability and word-representability of near-triangulationsMay 05 2016Oct 20 2016A graph $G = (V,E)$ is word-representable if there is a word $w$ over the alphabet $V$ such that $x$ and $y$ alternate in $w$ if and only if the edge $(x, y)$ is in $G$. It is known \cite{HKP2015} that all $3$-colourable graphs are word-representable, ... More
Finite-temperature perturbation theory for quasi-one-dimensional spin-1/2 Heisenberg antiferromagnetsOct 20 2001We develop a finite-temperature perturbation theory for quasi-one-dimensional quantum spin systems, in the manner suggested by H.J. Schulz (1996) and use this formalism to study their dynamical response. The corrections to the random-phase approximation ... More
Comparing Gröbner bases and word reversingDec 04 2007Gr\"obner bases, in their noncommutative version, and word reversing are methods for solving the word problem of a presented monoid, and both rely on iteratively completing the initial list of relations. Simple examples may suggest to conjecture that ... More
Elementary knot theoryApr 13 2016The aim of this survey article is to highlight several notoriously intractable problems about knots and links, as well as to provide a brief discussion of what is known about them.
Powers of ideals and the cohomology of stalks and fibers of morphismsSep 07 2010Feb 09 2012We first provide here a very short proof of a refinement of a theorem of Kodiyalam and Cutkosky, Herzog and Trung on the regularity of powers of ideals. This result implies a conjecture of H\`a and generalizes a result of Eisenbud and Harris concerning ... More
Oriented cohomology, Borel-Moore homology and algebraic cobordismJul 14 2008We examine various versions of oriented cohomology and Borel-Moore homology theories in algebraic geometry and put these two together in the setting of an "oriented duality theory", a generalization of Bloch-Ogus twisted duality theory. This combines ... More
Precision Measurements of the Hyperfine Structure in the 23P State of 3HeMar 13 2012The unusually large hyperfine structure splittings in the 23P state of the 3He isotope is measured using electro-optic techniques with high precision laser spectroscopy. Originally designed to probe the fine structure of the 4He atom, this experimental ... More
A quadratic refinement of the Grothendieck-Lefschetz-Verdier trace formulaSep 24 2013Aug 28 2014We prove a trace formula in stable motivic homotopy theory over a general base scheme, equating the trace of an endomorphism of a smooth proper scheme with the "Euler characteristic integral" of a certain cohomotopy class over its scheme of fixed points. ... More