Results for "Marc Wrona"

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Primitive Equations with Horizontal Viscosity: The Initial Value and the Time-Periodic Problem for Physical Boundary ConditionsFeb 08 2019The $3D$-primitive equations with only horizontal viscosity are considered on a cylindrical domain $(-h,h)\times G$, $G\subset \mathbb{R}^2$ smooth, with the physical Dirichlet boundary conditions on the sides. Instead of considering a vanishing vertical ... More
Rigorous justification of the hydrostatic approximation for the primitive equations by scaled Navier-Stokes equationsAug 07 2018Consider the anisotropic Navier-Stokes equations as well as the primitive equations. It is shown that the horizontal velocity of the solution to the anisotropic Navier-Stokes equations in a cylindrical domain of height $\varepsilon $ with initial data ... More
CoFeB/MgO/CoFeB structures with orthogonal easy axes: perpendicular anisotropy and dampingFeb 20 2019We report on the Gilbert damping parameter $\alpha$, the effective magnetization $4\pi M_{eff}$, and the asymmetry of the $g$-factor in bottom-CoFeB(0.93~nm)/MgO(0.90--1.25~nm)/CoFeB(1.31~nm)-top as-deposited systems. Magnetization of CoFeB layers exhibits ... 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
Entropy Rates of the Multidimensional Moran Processes and GeneralizationsJan 13 2014The interrelationships of the fundamental biological processes natural selection, mutation, and stochastic drift are quantified by the entropy rate of Moran processes with mutation, measuring the long-run variation of a Markov process. The entropy rate ... More
A Population-centric Approach to the Beauty Contest GameMay 07 2010Dec 13 2014An population-centric analysis for a version of the p-beauty contest game is given for the two-player, finite population, and infinite population cases. Winning strategies are characterized in terms of iterative thinking relative to the population. To ... More
Learning a world model and planning with a self-organizing, dynamic neural systemJun 11 2003We present a connectionist architecture that can learn a model of the relations between perceptions and actions and use this model for behavior planning. State representations are learned with a growing self-organizing layer which is directly coupled ... More
Charts, Interaction-Free Grammars, and the Compact Representation of AmbiguityMay 12 1997Recently researchers working in the LFG framework have proposed algorithms for taking advantage of the implicit context-free components of a unification grammar [Maxwell 96]. This paper clarifies the mathematical foundations of these techniques, provides ... More
Studies in Cryptological CombinatoricsNov 24 2004The key-agreement problem (finding a private key to use for secret messages, otherwise referred to as the public-key distribution problem), was introduced by Diffie and Hellman in 1976. An approach to structuring key-agreement protocols via the use of ... More
Extending Classical Logic with Inductive DefinitionsMar 07 2000The goal of this paper is to extend classical logic with a generalized notion of inductive definition supporting positive and negative induction, to investigate the properties of this logic, its relationships to other logics in the area of non-monotonic ... More
A partonic description of the transverse target single-spin asymmetry in inclusive DISNov 15 2012The single-spin asymmetry of unpolarized leptons scattering deep-inelastically off transversely polarized nucleons is studied in a partonic picture within a collinear twist-3 framework. Since this observable is generated by multi-photon exchanges between ... More
The Classical Exchange Algebra of AdS5 x S5 String TheoryOct 22 2008Jan 07 2009The classical exchange algebra satisfied by the monodromy matrix of AdS5 x S5 string theory in the Green-Schwarz formulation is determined by using a first-order Hamiltonian formulation and by adding to the Bena-Polchinski-Roiban Lax connection terms ... More
How to compute the thermodynamics of a glass using a cloned liquidDec 02 1998The recently proposed strategy for studying the equilibrium thermodynamics of the glass phase using a molecular liquid is reviewed and tested in details on the solvable case of the $p$-spin model. We derive the general phase diagram, and confirm the validity ... More
An extension criterion for lattice actions on the circleMay 01 2009We establish a necessary and sufficient condition for an action of a lattice by homeomorphisms of the circle to extend continuously to the ambient locally compact group. This condition is expressed in terms of the real bounded Euler class of this action. ... More
Higher indicators for some groups and their doublesApr 11 2010In this paper we explicitly determine all indicators for groups isomorphic to the semidirect product of two cyclic groups by an automorphism of prime order, as well as the generalized quaternion groups. We then compute the indicators for the Drinfel'd ... More
Scalar Mediated FCNC at the First Muon ColliderJun 14 2000Jun 26 2000In the most general two-Higgs doublet model (generally referred to as Model III), tree level flavor changing neutral couplings exist. It has been noted that the most natural value for such a coupling is of the order of the geometric mean of the Yukawa ... More
Fourth Generation b-prime decays into b + HiggsAug 04 1999Aug 08 1999If a fourth generation quark exists whose mass is below 255 GeV, then the only two-body charged current decay, b'-->cW, is doubly-Cabibbo suppressed. For this reason, CDF has searched for the one-loop neutral current decay b' --> bZ, assuming that the ... More
New Bounds on R-Parity Violating CouplingsOct 17 1995Bounds on R-parity violating couplings in the supersymmetric standard model are reviewed, and some new bounds arising from non-observation of certain rare B-decays (such as $B \rightarrow K^+K^-$) are presented. The focus is on baryon-number violating ... More
Motions on n-Simplex Graphs with m-value memoryOct 01 2003We introduce the idea of an n-simplex graph and games upon simplicial complexes. We then define moves on a labeled graph and pose the problem of whether given two labelings of a graph it is possible to change one into another via these moves. We then ... More
The Complexity of Partition Functions on Hermitian MatricesApr 07 2010Partition functions of certain classes of "spin glass" models in statistical physics show strong connections to combinatorial graph invariants. Also known as homomorphism functions they allow for the representation of many such invariants, for example, ... More
The asymptotic behaviour of Heegaard genusOct 21 2002Nov 26 2003Let M be a closed orientable 3-manifold with a negatively curved Riemannian metric. Let {M_i} be a collection of finite regular covers with degree d_i. (1) If the Heegaard genus of M_i grows more slowly than the square root of d_i, then M_i has positive ... More
The canonical decomposition of once-punctured torus bundlesDec 20 2001In this paper, we determine the canonical polyhedral decomposition of every hyperbolic once-punctured torus bundle over the circle. In fact, we show that the only ideal polyhedral decomposition that is straight in the hyperbolic structure and that is ... More
Expanders, rank and graphs of groupsMar 08 2004Apr 01 2005Let G be a finitely presented group, and let {G_i} be a collection of finite index normal subgroups that is closed under intersections. Then, we prove that at least one of the following must hold: 1. G_i is an amalgamated free product or HNN extension, ... More
Arithmetic of rationaly connected quintic 3-folds over finite and function fieldsOct 23 2007We prove that both classical Chevalley-Warning-Ax and Tsen theorems hold for the blowing up of a quintic 3-fold along a line of multiplicity 3. Both proofs, which are of the same spirit than the original ones, involve the description of this blowing-up ... More
Forces between static-light mesonsAug 09 2010The isospin, spin and parity dependent potential of a pair of static-light mesons is computed using Wilson twisted mass lattice QCD with two flavors of degenerate dynamical quarks. From the results a simple rule can be deduced stating, which isospin, ... More
On the Pseudo-Schrödinger Equation approximation of the Transfer-Integral operator for 1-dimensional DNA modelsNov 19 2010The Transfer-Integral (TI) operator is a powerful method to investigate the statistical physics of 1-dimensional models, like those used to describe DNA denaturation. At the cost of a certain number of approximations, the TI equation can be reduced to ... More
Isotropic realizability of a strain field for the incompressible two-dimensional Stokes equationSep 17 2015In the paper we study the problem of the isotropic realizability in R^2 of a regular strain field e(U)=1/2(DU+DU^T) for the incompressible Stokes equation, namely the existence of a positive viscosity mu\textgreater{}0 solving the Stokes equation in R^2 ... More
Higher Galois theoryJun 23 2015Jul 22 2015We generalize toposic Galois theory to higher topoi. We show that locally constant sheaves in a locally (n-1)-connected n-topos are equivalent to representations of its fundamental pro-n-groupoid, and that the latter can be described in terms of Galois ... More
Mean-field message-passing equations in the Hopfield model and its generalizationsAug 04 2016Aug 25 2016Motivated by recent progress in using restricted Boltzmann machines as preprocessing algorithms for deep neural network, we revisit the mean-field equations (belief-propagation and TAP equations) in the best understood such machine, namely the Hopfield ... More
Hilbertian InterpolationJun 25 2016I want to prove that all classical techniques of interpolation and approximation as Lagrange, Taylor, Hermite interpolations Beziers interpolants, Quasi interpolants, Box splines and others (radial splines, simplicial splines) are derived from a \textbf{unique} ... More
On equivariant homotopy theory for model categoriesAug 04 2013Feb 16 2016We introduce and compare two approaches to equivariant homotopy theory in a topological or ordinary Quillen model category. For the topological model category of spaces, we generalize Piacenza's result that the categories of topological presheaves indexed ... More
Covering spaces of 3-orbifoldsAug 01 2005Jun 07 2006Let O be a compact orientable 3-orbifold with non-empty singular locus and a finite volume hyperbolic structure. (Equivalently, O is the quotient of hyperbolic 3-space by a lattice in PSL(2,C) with torsion.) Then we prove that O has a tower of finite-sheeted ... More
Detecting large groupsFeb 20 2007Let G be a finitely presented group, and let p be a prime. Then G is 'large' (respectively, 'p-large') if some normal subgroup with finite index (respectively, index a power of p) admits a non-abelian free quotient. This paper provides a variety of new ... More
Mirror graphs: graph theoretical characterization of reflection arrangements and finite Coxeter groupsSep 02 2016Mirror graphs were introduced by Bre\v{s}ar et al. in 2004 as an intriguing class of graphs: vertex-transitive, isometrically embeddable into hypercubes, having a strong connection with regular maps and polytope structure. In this article we settle the ... More
Rigorous Multiple-Precision Evaluation of D-Finite Functions in SageMathJul 07 2016We present a new open source implementation in the SageMath computer algebra system of algorithms for the numerical solution of linear ODEs with polynomial coefficients. Our code supports regular singular connection problems and provides rigorous error ... More
Explicit GL(2) trace formulas and uniform, mixed Weyl lawsDec 18 2012This thesis provides an explicit, general trace formula for the Hecke and Casimir eigenvalues of GL(2)-automorphic representations over a global field. In special cases, we obtain Selberg's original trace formula. Computations for the determinant of the ... More
Dual-Phase Liquid Xenon Detectors for Dark Matter SearchesMay 29 2014Aug 07 2014Dual-phase time projection chambers (TPCs) filled with the liquid noble gas xenon (LXe) are currently the most sensitive detectors searching for interactions of WIMP dark matter in a laboratory-based experiment. This is achieved by combining a large, ... More
On Okuyama's theorems about Alvis-Curtis dualityOct 06 2008The purpose of this paper is to report on the unpublished manuscript [O] by T. Okuyama where are proved some conjectures generalizing to homotopy categories the theorems of [CaRi] and [LS] holding in derived categories. We refer to the latter references ... More
Escort Evolutionary Game TheoryNov 09 2009Feb 24 2012A family of replicator-like dynamics, called the escort replicator equation, is constructed using information-geometric concepts and generalized information entropies and diverenges from statistical thermodynamics. Lyapunov functions and escort generalizations ... More
The Inherent Randomness of Evolving PopulationsMar 08 2013Mar 27 2013The entropy rates of the Wright-Fisher process, the Moran process, and generalizations are computed and used to compare these processes and their dependence on standard evolutionary parameters. Entropy rates are measures of the variation dependent on ... More
Smooth motivesJul 14 2008Following ideas of Bondarko, we construct a DG category whose homotopy category is equivalent to the full subcategory of motives over a base-scheme $S$ generated by the motives of smooth projective $S$-schemes, assuming that $S$ is itself smooth over ... More
Pseudo-Riemannian metrics with prescribed scalar curvatureSep 22 2004Sep 22 2004We consider the following generalisation of a well-known problem in Riemannian geometry: When is a smooth real-valued function s on a given compact n-dimensional manifold M (with or without boundary) the scalar curvature of some smooth pseudo-Riemannian ... More
Lorentz-diffeomorphism edge modes in 3d gravityDec 14 2017Feb 08 2018The proper definition of subsystems in gauge theory and gravity requires an extension of the local phase space by including edge mode fields. Their role is on the one hand to restore gauge invariance with respect to gauge transformations supported on ... More
Remainder Padé approximants for the Hurwitz zeta functionSep 15 2017Following our earlier research, we use the method introduced by the author in \cite{prevost1996} named Remainder Pad\'e Approximant in \cite{rivoalprevost}, to construct approximations of the Hurwitz zeta function. We prove that these approximations are ... More
A Combinatorial Formula for Test Functions with Pro-p Iwahori Level StructureAug 27 2017The Test Function Conjecture due to Haines and Kottwitz predicts that the geometric Bernstein center is a source of test functions required by the Langlands-Kottwitz method for expressing the local semisimple Hasse-Weil zeta function of a Shimura variety ... More
Subdifferential stability and subdifferential sum rulesDec 30 2018In the first part, we discuss the stability of the strong slope and of the subdifferential of a lower semicontinuous function with respect to Wijsman perturbations of the function, i.e. perturbations described via Wijsman convergence. In the second part, ... More
Decomposition and pointwise estimates of periodic Green functions of some elliptic equations with periodic oscillatory coefficientsJul 24 2018This article is about the $\mathbb{Z}^d$-periodic Green function $G_n(x,y)$ of the multiscale elliptic operator $Lu=-{\rm div}\left( A(n\cdot) \cdot \nabla u \right)$, where $A(x)$ is a $\mathbb{Z}^d$-periodic, coercive, and H\"older continuous matrix, ... More
Recurrence relations for Apostol-Bernoulli , -Euler and -Genocchi polynomials of higher orderSep 15 2017In \cite{luo2006,luosri2005}, Luo and Srivastava introduced some generalizations of the Apostol -Bernoulli polynomials and the Apostol-Euler polynomials. The main object of this paper is to extend the result of \cite{prevost2010} to these generalized ... More
CCNx 1.0 Bidirectional StreamsJul 15 2017In Content Centric Networks, where one retrieves data based on a given name, not a conventional connection to a server or other device, there is a need for a standard mechanism to establish bi-directional streams. We describe a method to open and maintain ... More
Shifted moments of L functions and moments of theta functionsDec 03 2015Dec 04 2015Assuming the Riemann Hypothesis, Soundararajan showed that $\displaystyle{\int_{0}^{T} \vert \zeta(1/2 + it)\vert^{2k} \ll T(\log T)^{k^2 + \epsilon}}$ . His method was used by Chandee to obtain upper bounds for shifted moments of the Riemann Zeta function. ... More
A topological version of the Poincaré-Birkhoff theorem with two fixed pointsOct 18 2010Mar 30 2011The main result of this paper gives a topological property satisfied by any homeomorphism of the annulus $\mathbb{A}=\mathbb{S}^1 \times [-1,1]$ isotopic to the identity and with at most one fixed point. This generalizes the classical Poincar\'e-Birkhoff ... More
Overview of nucleon structure studiesOct 27 2007Nov 09 2007A brief overview of the recent activity in the measurement of the elastic electromagnetic proton and neutron form factors is presented. It is discussed how the quality of the data has been greatly improved by performing double polarization experiments, ... 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
From algebraic cobordism to motivic cohomologyOct 26 2012Aug 28 2014Let S be an essentially smooth scheme over a field of characteristic exponent c. Let MGL and HZ denote the algebraic cobordism spectrum and the motivic cohomology spectrum over S, respectively. We show that the canonical map MGL/(a1, a2, ...) -> HZ induced ... 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
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
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
Optimization and Physics: On the satisfiability of random Boolean formulaeDec 18 2002Dec 20 2002LECTURE GIVEN AT TH2002. Given a set of Boolean variables, and some constraints between them, is it possible to find a configuration of the variables which satisfies all constraints? This problem, which is at the heart of combinatorial optimization and ... 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
Left determined model structures for locally presentable categoriesJan 12 2009Jun 24 2009We extend a result of Cisinski on the construction of cofibrantly generated model structures from (Grothendieck) toposes to locally presentable categories and from monomorphism to more general cofibrations. As in the original case, under additional conditions, ... More
The crossing number of composite knotsMay 30 2008Aug 25 2009It is a very old conjecture that the crossing number of knots is additive under connected sum. In other words, if K#K' is the connected sum of knots K and K', then does the equality c(K#K') = c(K) + c(K') hold? We prove that c(K#K') is at most c(K) + ... More
Attaching handlebodies to 3-manifoldsSep 09 2001Jan 09 2003The main theorem of this paper is a generalisation of well known results about Dehn surgery to the case of attaching handlebodies to a simple 3-manifold. The existence of a finite set of `exceptional' curves on the boundary of the 3-manifold is established. ... 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
Properties of confining gauge field configurations in the pseudoparticle approachOct 23 2006The pseudoparticle approach is a numerical method to approximate path integrals in SU(2) Yang-Mills theory. Path integrals are computed by summing over all gauge field configurations, which can be represented by a linear superposition of a small number ... 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
Adding high powered relations to large groupsDec 15 2005Mar 29 2007A group is known as `large' if some finite index subgroup admits a surjective homomorphism onto a non-abelian free group. The main theorem of the paper is as follows. Let G be a finitely generated, large group and let g_1,...,g_r be a collection of elements ... 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
A characterisation of large finitely presented groupsMar 08 2004Apr 01 2005A group is known as `large' if some finite index subgroup admits a surjective homomorphism onto a non-abelian free group. In this paper, we give a necessary and sufficient condition for a finitely presented group to be large, in terms of the existence ... More
Stability and angular-momentum transport of fluid flows between corotating cylindersMar 22 2012Turbulent transport of angular momentum is a necessary process to explain accretion in astrophysical disks. Although the hydrodynamic stability of disk-like flows has been tested in experiments, results are contradictory and suggest either laminar or ... More
A remark on renormalized volume and Euler characteristic for ACHE 4-manifoldsMay 09 2003May 16 2004This note computes the "renormalized volume" and a renormalizedGauss-Bonnet-Chern formula for the Euler characteristic ofasymptotically complex hyperbolic Einstein (in short: ACHE)4-manifolds.
Statistical mechanics of two-dimensional foams: Physical foundations of the modelJul 16 2015Jan 11 2016In a recent series of papers [1--3], a statistical model that accounts for correlations between topological and geometrical properties of a two-dimensional shuffled foam has been proposed and compared with experimental and numerical data. Here, the various ... More
Optimizing the bulk modulus of cellular networksApr 05 2005We present an alternative derivation of upper-bounds for the bulk modulus of both two-dimensional and three-dimensional cellular materials. For two-dimensional materials, we recover exactly the expression of the Hashin-Shtrikman (HS) upper-bound in the ... 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.
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
Extremality for the Vafa-Witten bound on the sphereJul 30 2004Nov 29 2004We prove that the round metric on the sphere has the largest first eigenvalue of the Dirac operator among all metrics that are larger than it. As a corollary, this gives an alternative proof of an extremality result for scalar curvature due to M. Llarull. ... 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
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
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
Characterization of the monotone polar of subdifferentialsJul 07 2013We show that a point is solution of the Minty variational inequality of subdifferential type for a given function if and only if the function is increasing along rays starting from that point. This provides a characterization of the monotone polar of ... 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
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
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
A metric graph satisfying $w^1_4=1$ that cannot be lifted to a curve satisfying $\dim (W^1_4)=1$Jan 15 2015For all integers $g \geq 6$ we prove the existence of a metric graph $G$ with $w^1_4=1$ such that $G$ has Clifford index 2 and there is no tropical modification $G'$ of $G$ such that there exists a finite harmonic morphism of degree 2 from $G'$ to a metric ... More
The separating gonality of a separating real curveSep 11 2011A smooth real curve is called separating in case the complement of the real locus inside the complex locus is disconnected. This is the case if there exists a morphism to the projective line whose inverse image of the real locus of the projective line ... More
Segregative phase separation scenario of the formation of the bacterial nucleoidSep 19 2018The mechanism responsible for the compaction of the genomic DNA of bacteria inside a structure called the nucleoid is a longstanding but still lively debated question. Most puzzling is the fact that the nucleoid occupies only a small fraction of the cell, ... More
Configuration Space Singularities of The Delta ManipulatorAug 29 2018We investigate the configuration space of the Delta-Manipulator, identify 24 points in the configuration space, where the Jacobian of the Constraint Equations looses rank and show, that these are not manifold points of the Real Algebraic Set, which is ... More
How Problematic is the Near-Euclidean Spatial Geometry of the Large-Scale Universe?Mar 14 2018Oct 15 2018Modern observations based on general relativity indicate that the spatial geometry of the expanding, large-scale Universe is very nearly Euclidean. This basic empirical fact is at the core of the so-called "flatness problem", which is widely perceived ... More
Links between functions and subdifferentialsFeb 17 2018Oct 15 2018A function in a class $\mathcal{F}(X)$ is said to be subdifferentially determined in $\mathcal{F}(X)$ if it is equal up to an additive constant to any function in $\mathcal{F}(X)$ with the same subdifferential. A function is said to be subdifferentially ... More
Modular hyperbolas and Beatty sequencesAug 01 2018Aug 02 2018Bounds for $\max\{m,\tilde{m}\}$ subject to $m,\tilde{m} \in \mathbb{Z}\cap[1,p)$, $p$ prime, $z$ indivisible by $p$, $m\tilde{m}\equiv z\bmod p$ and $m$ belonging to some fixed Beatty sequence $\{ \lfloor n\alpha+\beta \rfloor : n\in\mathbb{N} \}$ are ... More
Local methods for blocks of finite simple groupsDec 24 2017This survey is about old and new results about the modular representation theory of finite reductive groups with a strong emphasis on local methods. This includes subpairs, Brauer's Main Theorems, fusion, Rickard equivalences. In the defining characteristic ... More
Non-resonant tori in symplectic twist maps without conjugate pointsFeb 08 2018We study the dynamics of a symplectic twist map without conjugate points. We show that in a neighborhood of a totally periodic Lagrangian manifold, there exists a large family of invariant Lagrangian tori on which the twist map is conjugated to a translation ... More