Results for "Georg Moragas-Klostermeyer"

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Jovian Dust Streams: A monitor of Io's volcanic plume activitySep 01 2003Streams of high speed dust particles originate from Jupiter's innermost Galilean moon Io. After release from Io, the particles collect electric charges in the Io plasma torus, gain energy from the co-rotating electric field of Jupiter's magnetosphere, ... More
A boundedness theorem for cone singularitiesDec 11 2018A cone singularity is a normal affine variety $X$ with an effective one-dimensional torus action with a unique fixed point $x\in X$ which lies in the closure of any orbit of the $k^*$-action. In this article, we prove a boundedness theorem for cone singularities ... More
On minimal log discrepancies and Kollár componentsOct 24 2018In this article we prove a local implication of boundedness of Fano varieties. More precisely, we prove that $d$-dimensional $a$-log canonical singularities, with standard coefficients, which admit an $\epsilon$-plt blow-up have minimal log discrepancies ... More
On a notion of toric special linear systemsDec 31 2015Mar 12 2018In this note we study linear systems on complete toric varieties $X$ with an invariant point, whose orbit under the action of the automorphism group of $X$ contains the dense torus $T$ of $X$. We give a characterization of such varieties in terms of its ... More
Two oscillators quantum groups and associated deformed coherent statesMar 21 2005Starting from a faithful five-dimensional matrix representation of the group of two independent oscillators and applying the R-matrix method we generate some classes of deformed fermionic-bosonic quantum Hopf algebras. The corresponding Lie deformed superalgebras ... More
A symbolic calculus for a class of quantum computing circuitsApr 27 2015This paper introduces a symbolic calculus to evaluate the output signals at the target line(s) of quantum computing subcircuits using controlled negations and controlled-Q gates, where Q represents the k-th root of [0 1; 1 0], the unitary matrix of NOT, ... More
sh(2/2) Superalgebra eigenstates and generalized supercoherent and supersqueezed statesApr 06 2005The superalgebra eigenstates (SAES) concept is introduced and then applied to find the SAES associated to the $sh(2/2)$ superalgebra, also known as Heisenberg--Weyl Lie superalgebra. This implies to solve a Grassmannian eigenvalue superequation. Thus, ... More
Generalized coherent and squeezed states based on the $h(1) \otimes su(2)$ algebraMar 26 2005States which minimize the Schr\"odinger--Robertson uncertainty relation are constructed as eigenstates of an operator which is a element of the $h(1) \oplus \su(2)$ algebra. The relations with supercoherent and supersqueezed states of the supersymmetric ... More
Cohen-Macaulay Du Bois singularities with a torus action of complexity oneJun 21 2018Using Altmann-Hausen-S\"u\ss\ description of T-varieties via divisorial fans and K\'ovacs-Schwede-Smith characterization of Du Bois singularities we prove that any rational T-variety of complexity one which is Cohen-Macaulay and Du Bois has rational singularities. ... More
Determining neutralino parameters in Left-Right Supersymmetric ModelsOct 04 2005We report exact analytical expressions relating the fundamental parameters describing the neutralino sector in the context of the left-right supersymmetric model. The method used for such a effects is the projector formalism deduced without take into ... More
Explicit thermostatics of certain classical one-dimensional lattice models by harmonic analysisMar 28 1994A certain class of one-dimensional classical lattice models is considered. Using the method of abstract harmonic analysis explicit thermostatic properties of such models are derived. In particular, we discuss the low-temperature behavior of some of these ... More
Exchange currents in radiative hyperon decays and hyperon charge radiiOct 06 1998Radiative decays of decuplet hyperons and octet hyperon charge radii are evaluated in a chiral constituent quark model emphasizing the role of exchange currents. Exchange currents largely cancel for the M1 decay amplitudes, while they dominate the E2 ... More
Injective completion with respect to homologyDec 19 2004Generalizing F-nilpotent completion for a ring spectrum F we first define the notion of completion with respect to a thick subcategory in a monogenic stable homotopy category. Specializing this to the thick subcategory generated by F-injectives gives ... More
An extension theorem for hermitian line bundlesJul 22 2015May 11 2016We prove a general extension theorem for holomorphic line bundles on reduced complex spaces, equipped with singular hermitian metrics, whose curvature currents can be extended as positive, closed currents. The result has applications to various moduli ... More
Complex-Valued Random Vectors and Channels: Entropy, Divergence, and CapacityMay 04 2011Recent research has demonstrated significant achievable performance gains by exploiting circularity/non-circularity or propeness/improperness of complex-valued signals. In this paper, we investigate the influence of these properties on important information ... More
A note on random samples of Lie algebrasJul 09 2014Recently, Paiva and Teixeira (arXiv:1108.4396) showed that the structure constants of a Lie algebra are the solution of a system of linear equations provided a certain subset of the structure constants are given a-priori. Here it is noted that Lie algebras ... More
Silent Transitions in Automata with StorageFeb 15 2013We consider the computational power of silent transitions in one-way automata with storage. Specifically, we ask which storage mechanisms admit a transformation of a given automaton into one that accepts the same language and reads at least one input ... More
On the capabilities of grammars, automata, and transducers controlled by monoidsMar 17 2011During the last decades, classical models in language theory have been extended by control mechanisms defined by monoids. We study which monoids cause the extensions of context-free grammars, finite automata, or finite state transducers to exceed the ... More
Gromov-Witten invariants of the Hilbert schemes of points of a K3 surfaceJun 04 2014Nov 03 2015We study the enumerative geometry of rational curves on the Hilbert schemes of points of a K3 surface. Let $S$ be a K3 surface and let $\mathsf{Hilb}^d(S)$ be the Hilbert scheme of $d$ points of $S$. In case of elliptically fibered K3 surfaces $S \to ... More
A Brascamp-Lieb type covariance estimateFeb 20 2014In this article, we derive a new covariance estimate. The estimate has a similar structure as the Brascamp-Lieb inequality and is optimal for ferromagnetic Gaussian measures. It can be naturally applied to deduce decay of correlations of lattice systems ... More
Abstract tropical linear programmingDec 06 2016Dec 04 2017In this paper we develop a combinatorial abstraction of tropical linear programming. This generalizes the search for a feasible point of a system of min-plus-inequalities. It is based on the polyhedral properties of triangulations of the product of two ... More
Dynamics of a Continuous Piecewise Affine Map of the SquareMay 18 2013We present a one-parameter family of continuous, piecewise affine, area preserving maps of the square, which are inspired by a dynamical system in game theory. Interested in the coexistence of stochastic and (quasi-)periodic behaviour, we investigate ... More
Quantum and classical stochastic dynamics: Exactly solvable models by supersymmetric methodsOct 23 1998A supersymmetric method for the construction of so-called conditionally exactly solvable quantum systems is reviewed and extended to classical stochastic dynamical systems characterized by a Fokker-Planck equation with drift. A class of drift-potentials ... More
Exchange Currents in Radiative Hyperon DecaysJun 15 1998A short overview of motivations and successes of two-body exchange currents between constituent quarks for electromagnetic hadron observables like charge radii, magnetic and quadrupole moments is given. We then predict and analyze exchange current effects ... More
SU(r,L) is separably unirationalOct 22 2008We show that the moduli space of SU_X(r,L) of rank r bundles of fixed determinant L on a smooth projective curve X is separably unirational.
Raynaud vector bundlesJun 27 2007We construct vector bundles $R^r_\mu$ on a smooth projective curve $X$ having the property that for all sheaves $E$ of slope $\mu$ and rank $r$ on $X$ we have an equivalence: $E$ is a semistable vector bundle $\iff$ $Hom(R^r_\mu,E)=0$. As a byproduct ... More
Climate Modelling of Mass-Extinction Events: A ReviewJun 18 2009Despite tremendous interest in the topic and decades of research, the origins of the major losses of biodiversity in the history of life on Earth remain elusive. A variety of possible causes for these mass-extinction events have been investigated, including ... More
On the Throughput/Bit-Cost Tradeoff in CSMA Based Cooperative NetworksJun 05 2009Nov 04 2009Wireless local area networks (WLAN) still suffer from a severe performance discrepancy between different users in the uplink. This is because of the spatially varying channel conditions provided by the wireless medium. Cooperative medium access control ... More
Particle production sources at LHC energiesJan 09 2013Feb 18 2013Particle production sources at RHIC and LHC energies are investigated in pseudorapidity space. A nonequilibrium-statistical relativistic diffusion model (RDM) with three sources is applied to the analysis of charged-hadron distributions in AuAu collisions ... More
Optimal Non-Uniform Mapping for Probabilistic ShapingAug 06 2012Jul 07 2014The construction of optimal non-uniform mappings for discrete input memoryless channels (DIMCs) is investigated. An efficient algorithm to find optimal mappings is proposed and the rate by which a target distribution is approached is investigated. The ... More
An approach to computing downward closuresMar 03 2015Jun 01 2015The downward closure of a word language is the set of all (not necessarily contiguous) subwords of its members. It is well-known that the downward closure of any language is regular. While the downward closure appears to be a powerful abstraction, algorithms ... More
EXPODE -- Advanced Exponential Time Integration Toolbox for MATLABApr 17 2014We present a MATLAB toolbox for five different classes of exponential integrators for solving (mildly) stiff ordinary differential equations or time-dependent partial differential equations. For the efficiency of such exponential integrators it is essential ... More
Probabilistic Signal Shaping for Bit-Metric DecodingJan 23 2014Apr 20 2014A scheme is proposed that combines probabilistic signal shaping with bit-metric decoding. The transmitter generates symbols according to a distribution on the channel input alphabet. The symbols are labeled by bit strings. At the receiver, the channel ... More
The complexity of downward closure comparisonsMay 10 2016The downward closure of a language is the set of all (not necessarily contiguous) subwords of its members. It is well-known that the downward closure of every language is regular. Moreover, recent results show that downward closures are computable for ... More
On the Relation between Solar Activity and Clear-Sky Terrestrial IrradianceSep 04 2012Oct 09 2012The Mauna Loa Observatory record of direct-beam solar irradiance measurements for the years 1958-2010 is analysed to investigate the variation of clear-sky terrestrial insolation with solar activity over more than four solar cycles. The raw irradiance ... More
Limits on a CP-violating scalar axion-nucleon interactionMay 08 2012Jul 29 2012Axions or similar hypothetical pseudoscalar bosons may have a small CP-violating scalar Yukawa interaction g_s(N) with nucleons, causing macroscopic monopole-dipole forces. Torsion-balance experiments constrain g_p(e) g_s(N), whereas g_p(N) g_s(N) is ... More
Neutrinos and the starsJan 08 2012May 19 2012The role of neutrinos in stars is introduced for students with little prior astrophysical exposure. We begin with neutrinos as an energy-loss channel in ordinary stars and conversely, how stars provide information on neutrinos and possible other low-mass ... More
CP violation in $B^0_s$ mixing with LHCbDec 05 2011The determination of the CP-violating phase $\phi_s$ in $B^0_s \rightarrow J/\psi \phi$ decays is one of the key goals of the LHCb experiment. Its value is predicted to be very small in the Standard Model but can be significantly enhanced in many models ... More
Ultraviolet energy dependence of particle production sources in relativistic heavy-ion collisionsJan 13 2015The energy dependence of particle production sources in relativistic heavy-ion collisions is investigated from RHIC to LHC energies. Whereas charged-hadron production in the fragmentation sources follows a ln(s_NN/s_0) law, particle production in the ... More
Supersymmetry on the lattice and the status of the Super-Yang-Mills simulationsNov 03 2010Supersymmetry (SUSY) and supersymmetric field theories are an interesting topic for numerical lattice simulations. Similar to the chiral symmetry there is also no local realization of (interacting) supersymmetry on the lattice. I briefly review the basic ... More
The Relative Chern Character and RegulatorsJul 08 2010In this thesis we construct a modified version of Karoubi's relative Chern character for smooth varieties over the complex numbers or the ring of integers in a p-adic number field. Comparison results with the Deligne-Beilinson Chern character and the ... More
Curvature of higher direct images and applications (Curvature of $R^{n-p}f_*Ω^p_{X/S}(K_{X/S}^{\otimes m})$ and applications)Feb 25 2010May 19 2010Given an effectively parameterized family $f:X\to S$ of canonically polarized manifolds, the K\"ahler-Einstein metrics on the fibers induce a hermitian metric on the relative canonical bundle $K_{X/S}$. We use a global elliptic equation to show that this ... More
Gromov-Witten theory of K3 x P1 and quasi-Jacobi formsMay 17 2016Let $S$ be a K3 surface with primitive curve class $\beta$. We completely solve the relative Gromov-Witten theory of $S \times \mathbb{P}^1$ in classes $(\beta,1)$ and $(\beta,2)$. The generating series are quasi-Jacobi forms and equal to a corresponding ... More
The approach of Otto-Reznikoff revisitedSep 03 2013Apr 10 2014In this article we consider a lattice system of unbounded continuos spins. Otto & Reznikoff used the two-scale approach to show that exponential decay of correlations yields a logarithmic Sobolev inequality (LSI) with uniform constant in the system size. ... More
Minimal bundles and fine moduli spacesMar 13 2009We study sheaves E on a smooth projective curve X which are minimal with respect to the property that $h^0(E \otimes L) >0$ for all line bundles L of degree zero. We show that these sheaves define ample divisors D(E) on the Picard torus Pic(X). Next we ... More
Residual intersection theory with reducible schemesNov 07 2001We develop a formula (Theorem 5.1) which allows to compute top Chern classes of vector bundles on the vanishing locus $V(s)$ of a section of this bundle. This formula particularly applies in the case when $V(s)$ is the union of locally complete intersections ... More
EXPODE - Advanced Exponential Time Integration Toolbox for MATLAB, Code DocumentationAug 12 2011Dec 08 2011EXPODE is a MATLAB toolbox for exponential time integration. It supports exponential Runge-Kutta- and Rosenbrock-methods, linearized and non-linearized multistep-methods and the EXP4. We support evaluation of the arising matrix functions either directly ... More
On the homotopy theory of n-typesApr 24 2006An n-truncated model structure on simplicial (pre-)sheaves is described having as weak equivalences maps that induce isomorphisms on certain homotopy sheaves only up to degree n. Starting from one of Jardine's intermediate model structures we construct ... More
Risk aggregation with empirical margins: Latin hypercubes, empirical copulas, and convergence of sum distributionsAug 11 2015This paper studies convergence properties of multivariate distributions constructed by endowing empirical margins with a copula. This setting includes Latin Hypercube Sampling with dependence, also known as the Iman--Conover method. The primary question ... More
Path-Integral Aspects of Supersymmetric Quantum MechanicsSep 02 1996In this talk we briefly review the concept of supersymmetric quantum mechanics using a model introduced by Witten. A quasi-classical path-integral evaluation for this model is performed, leading to a so-called supersymmetric quasi-classical quantization ... More
Recent Developments in Supersymmetric Quantum MechanicsMar 29 1994Apr 05 1994Some recent results in supersymmetric quantum mechanics are presented. New semi-classical approximation formulas for Witten's realization of supersymmetric quantum mechanics are discussed. Implications of the supersymmetric structure of Pauli's Hamiltonian ... More
Acceleration of GRB outflows by Poynting flux dissipationDec 21 2001Jun 24 2002We study magnetically powered relativistic outflows in which a part of the magnetic energy is dissipated internally by reconnection. For GRB parameters, and assuming that the reconnection speed scales with the Alfven speed, significant dissipation can ... More
Restriction of stable rank two vector bundles in arbitrary characteristicApr 20 1999Let $X$ be a smooth variety defined over an algebraically closed field of arbitrary characteristic and $\O_X(H)$ be a very ample line bundle on $X$. We show that for a semistable $X$-bundle $E$ of rank two, there exists an integer $m$ depending only on ... More
Raynaud's vector bundles and base points of the generalized Theta divisorJul 14 2006We study base points of the generalized Theta-divisor on the moduli space of vector bundles on a smooth algebraic curve X of genus g defined over an algebraically closed field. To do so, we use the derived categories D(Pic(X)), D(Jac(X)), and the equivalence ... More
Pseudorapidity distributions of produced charged hadrons in pp collisions at RHIC and LHC energiesJun 18 2011The energy dependence of charged-hadron production in proton-proton collisions at RHIC and LHC energies is investigated in a nonequilibrium-statistical relativistic diffusion model (RDM) with three sources for particle production. Calculated charged-hadron ... More
Beyond the thermal model in relativistic heavy-ion collisionsMay 31 2016Jun 27 2016Deviations from thermal distribution functions of produced particles in relativistic heavy-ion collisions are discussed as indicators for nonequilibrium processes. The focus is on rapidity distributions of produced charged hadrons as functions of collision ... More
On the Expressive Power of Kleene Algebra with DomainJul 26 2015Aug 02 2015It is shown that antidomain semirings are more expressive than test semirings and that Kleene algebras with domain are more expressive than Kleene algebras with tests. It is also shown that Kleene algebras with domain are expressive for propositional ... More
Rooted Trees with Probabilities RevisitedFeb 04 2013Rooted trees with probabilities are convenient to represent a class of random processes with memory. They allow to describe and analyze variable length codes for data compression and distribution matching. In this work, the Leaf-Average Node-Sum Interchange ... More
The faint young Sun problemApr 19 2012For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the `faint young Sun problem'. For the early Earth, models of stellar evolution predict a solar energy input to the ... More
Motion of inertial particles in Gaussian fields driven by an infinite-dimensional fractional Brownian motionMar 18 2012We study the motion of an inertial particle in a fractional Gaussian random field. The motion of the particle is described by Newton's second law, where the force is proportional to the difference between a background fluid velocity and the particle velocity. ... More
Interpolation categories for homology theoriesDec 19 2004Feb 25 2006For a homological functor from a triangulated category to an abelian category satisfying some technical assumptions we construct a tower of interpolation categories. These are categories over which the functor factorizes and which capture more and more ... More
Divided Differences of Multivariate Implicit FunctionsFeb 29 2012Under general conditions, the equation $g(x^1, ..., x^q, y) = 0$ implicitly defines $y$ locally as a function of $x^1, ..., x^q$. In this article, we express divided differences of $y$ in terms of divided differences of $g$, generalizing a recent formula ... More
Implicit Divided Differences, Little Schröder Numbers, and Catalan NumbersApr 12 2012Jan 31 2015Under general conditions, the equation $g(x,y) = 0$ implicitly defines $y$ locally as a function of $x$. In this short note we study the combinatorial structure underlying a recently discovered formula for the divided differences of $y$ expressed in terms ... More
Positivity of relative canonical bundles and applicationsJan 13 2012Given a family $f:\mathcal X \to S$ of canonically polarized manifolds, the unique K\"ahler-Einstein metrics on the fibers induce a hermitian metric on the relative canonical bundle $\mathcal K_{\mathcal X/S}$. We use a global elliptic equation to show ... More
Duality Construction of Moduli SpacesAug 29 1997We show for the moduli space of rank-2 coherent sheaves on an algebraic surface that there exists a 'dual' moduli space. This dual space allows a construction of the first one without using the GIT construction. Furthermore, we obtain a Barth-morphism, ... More
Weyl Groups with Coxeter Presentation and Presentation by ConjugationJul 22 2006We investigate which Weyl groups have a Coxeter presentation and which of them at least have the presentation by conjugation with respect to their root system. For most concepts of root systems the Weyl group has both. In the context of extended affine ... More
On reduced stable pair invariantsMay 16 2016Let $X = S \times E$ be the product of a K3 surface $S$ and an elliptic curve $E$. Reduced stable pair invariants of $X$ can be defined via (1) cutting down the reduced virtual class with incidence conditions or (2) the Behrend function weighted Euler ... More
A Serre derivative for even weight Jacobi FormsSep 25 2012Jun 11 2014Using deformed or twisted Eisenstein Series, we construct a Jacobi-Serre derivative on even-weight Jacobi forms that generalizes the classical Serre derivative on modular forms. As an application, we obtain Ramanujan equations for the index $1$ Eisenstein ... More
Generalized Albanese morphismsApr 04 2003Sep 27 2004We define generalizations of the Albanese variety for a projective variety X. The generalized Albanese morphisms X --> Alb_r(X) contract those curves C in X for which the induced morphism Hom(\pi_1(X),U(r)) --> Hom(\pi_1(C),U(r)) has a finite image. Thus, ... More
Produced charged hadrons in central Pb + Pb collisions at LHC energies in the RDMFeb 16 2011Apr 13 2011The energy dependence of charged-hadron production in relativistic heavy-ion collisions is investigated in a nonequilibrium-statistical relativistic diffusion model (RDM) with three sources. Theoretical pseudorapidity distributions are compared with Au ... More
Computing downward closures for stacked counter automataSep 28 2014The downward closure of a language $L$ of words is the set of all (not necessarily contiguous) subwords of members of $L$. It is well known that the downward closure of any language is regular. Although the downward closure seems to be a promising abstraction, ... More
Proof Theory at Work: Complexity Analysis of Term Rewrite SystemsJul 31 2009Dec 30 2009This thesis is concerned with investigations into the "complexity of term rewriting systems". Moreover the majority of the presented work deals with the "automation" of such a complexity analysis. The aim of this introduction is to present the main ideas ... More
On the line-symmetry of self-motions of linear pentapodsOct 13 2015Dec 01 2015We show that all self-motions of pentapods with linear platform of Type 1 and Type 2 can be generated by line-symmetric motions. Thus this paper closes a gap between the more than 100 year old works of Duporcq and Borel and the extensive study of line-symmetric ... More
Accelerated Portfolio Optimization with Conditional Value-at-Risk Constraints using a Cutting-Plane MethodAug 12 2014Financial portfolios are often optimized for maximum profit while subject to a constraint formulated in terms of the Conditional Value-at-Risk (CVaR). This amounts to solving a linear problem. However, in its original formulation this linear problem has ... More
Symbols and exact regularity of symmetric pseudo-splines of any arityNov 02 2016Pseudo-splines form a family of subdivision schemes that provide a natural blend between interpolating schemes and approximating schemes, including the Dubuc-Deslauriers schemes and B-spline schemes. Using a generating function approach, we derive expressions ... More
Fixed Point Theorem for Non-Self Maps of Regions in the PlaneDec 15 2011May 03 2013Let X and Y be compact, simply connected and locally connected subsets of R^2, and let f : X -> Y be a homeomorphism isotopic to the identity on X. Generalizing Brouwer's plane translation theorem for self-maps of the plane, we prove that f has no recurrent ... More
The Cosmic Dust Analyzer onboard Cassini: ten years of discoveriesFeb 13 2018The interplanetary space probe Cassini/Huygens reached Saturn in July 2004 after seven years of cruise phase. The Cosmic Dust Analyzer (CDA) measures the interplanetary, interstellar and planetary dust in our solar system since 1999 and provided unique ... More
AXIONS IN ASTROPHYSICS AND COSMOLOGYFeb 21 1995Mar 23 1995If axions exist they are efficiently produced in the hot and dense interior of stars, providing a novel energy-loss mechanism. In order to avoid a conflict with the observed properties of stars, one can derive a lower limit on the Peccei-Quinn scale (an ... More
Positivity of relative canonical bundles for families of canonically polarized manifoldsAug 25 2008Oct 19 2010Given an effectively parameterized family of canonically polarized manifolds the Kaehler-Einstein metrics on the fibers induce a hermitian metric on the relative canonical bundle. We use a global elliptic equation to show that this metric is strictly ... More
Truncated resolution model structuresFeb 25 2006Using the dual of Bousfield-Friedlander localization we colocalize resolution model structures on cosimplicial objects over a left proper model category to get truncated resolution model structures. These are useful to study realization and moduli problems ... More
Achievable Rates for Shaped Bit-Metric DecodingOct 29 2014May 28 2016A new achievable rate for bit-metric decoding (BMD) is derived using random coding arguments. The rate expression can be evaluated for any input distribution, and in particular the bit-levels of binary input labels can be stochastically dependent. Probabilistic ... More
Arithmetics with multiple testing proceduresJul 14 2016Statistical discoveries are often obtained through multiple hypothesis testing. A variety of procedures exists to evaluate multiple hypotheses, for instance the ones of Benjamini-Hochberg, Bonferroni, Holm or Sidak. We are particularly interested in multiple ... More
Lecture Notes on Channel CodingJul 04 2016These lecture notes on channel coding were developed for a one-semester course for graduate students of electrical engineering. Chapter 1 reviews the basic problem of channel coding. Chapters 2-5 are on linear block codes, cyclic codes, Reed-Solomon codes, ... More
On an analytic version of Lazard's isomorphismAug 19 2014Apr 06 2015We prove a comparison theorem between locally analytic group cohomology and Lie algebra cohomology for locally analytic representations of a Lie group over a nonarchimedean field of characteristic 0. The proof is similar to that of van-Est's isomorphism ... More
Importance sampling for the simulation of reinsurance lossesMar 30 2013Importance sampling is a well developed method in statistics. Given a random variable $X$, the problem of estimating its expected value $\mu$ is addressed. The standard approach is to use the sample mean as an estimator $\bar x$. In importance sampling, ... More
Karoubi's relative Chern character, the rigid syntomic regulator, and the Bloch-Kato exponential mapNov 17 2011Jul 21 2014We construct a variant of Karoubi's relative Chern character for smooth, separated schemes over the ring of integers in a p-adic field and prove a comparison with the rigid syntomic regulator. For smooth projective schemes we further relate the relative ... More
Deciding Monotone Duality and Identifying Frequent Itemsets in Quadratic LogspaceDec 09 2012Aug 22 2013The monotone duality problem is defined as follows: Given two monotone formulas f and g in iredundant DNF, decide whether f and g are dual. This problem is the same as duality testing for hypergraphs, that is, checking whether a hypergraph H consists ... More
On Minimal Constraint NetworksMar 08 2011Jul 25 2012In a minimal binary constraint network, every tuple of a constraint relation can be extended to a solution. The tractability or intractability of computing a solution to such a minimal network was a long standing open question. Dechter conjectured this ... More
Abstract tropical linear programmingDec 06 2016Analogously to classical oriented matroid programming, we give the first feasibility algorithm for signed tropical oriented matroids, which encode the structure of tropical linear inequality systems. The feasibility problem for tropical linear inequality ... More
L-stable functorsApr 19 2007We generalize and greatly simplify the approach of Lydakis and Dundas-R\"ondigs-{\O}stv{\ae}r to construct an L-stable model structure for small functors from a closed symmetric monoidal model category V to a V-model category M, where L is a small cofibrant ... More
Astrophysical Axion BoundsNov 28 2006Axion emission by hot and dense plasmas is a new energy-loss channel for stars. Observational consequences include a modification of the solar sound-speed profile, an increase of the solar neutrino flux, a reduction of the helium-burning lifetime of globular-cluster ... More
Comment on "Cherenkov Radiation by Neutrinos in a Supernova Core"Apr 18 1997Mohanty and Samal have shown that the magnetic-moment interaction with nucleons contributes significantly to the photon dispersion relation in a supernova core, and with an opposite sign relative to the usual plasma effect. Because of a numerical error ... More
The Nature of Dark MatterNov 10 1995The dynamics of the universe may be dominated by novel weakly interacting elementary particles, by baryons in an invisible form, by black holes, and globally by vacuum energy. The main arguments for and against such hypotheses are reviewed.
New Supernova Limit on Large Extra DimensionsMar 19 2001Jun 06 2001If large extra dimensions exist in nature, supernova (SN) cores will emit large fluxes of Kaluza-Klein gravitons, producing a cosmic background of these particles with energies and masses up to about 100 MeV. Radiative decays then give rise to a diffuse ... More
Geometric Approach to the Weil-Petersson Symplectic FormAug 27 2008Aug 28 2008In a family of compact, canonically polarized, complex manifolds the first variation of the lengths of closed geodesics is computed. As an application, we show the coincidence of the Fenchel-Nielsen and Weil-Petersson symplectic forms on the Teichmueller ... More
Frequency Dependent Conductance of a Tunnel Junction in the Semiclassical LimitFeb 01 1999The linear conductance of the a small metallic tunnel junction embedded in an electromagnetic environment of arbitrary impedance is determined in the semiclassical limit. Electron tunneling is treated beyond the orthodox theory of Coulomb blockade phenomena ... More
High Temperature Conductance of the Single Electron TransistorJun 09 1998Nov 13 1998The linear conductance of the single electron transistor is determined in the high temperature limit. Electron tunneling is treated nonperturbatively by means of a path integral formulation and the conductance is obtained from Kubo's formula. The theoretical ... More
Monadic Datalog and the Expressive Power of Languages for Web Information ExtractionNov 15 2002Oct 08 2003Research on information extraction from Web pages (wrapping) has seen much activity recently (particularly systems implementations), but little work has been done on formally studying the expressiveness of the formalisms proposed or on the theoretical ... More
On Quantum TheoryAug 24 2013Nov 21 2013Quantum theory is a well-defined local theory with a clear interpretation. No "measurement problem" or any other foundational matters are waiting to be settled.
Comment on "Minimum Uncertainty and Entanglement"Aug 04 2011Sep 03 2011Dass, Qureshi, and Sheel conjecture that the lower bound in the Heisenberg-Robertson uncertainty relation cannot be reached in mixed states. The conjecture is wrong.