Results for "Gerd Steinle-Neumann"

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Saturation and negative temperature coefficient of electrical resistivity in liquid iron-sulfur alloys at high densities from first principles calculationsMar 07 2018We report results on electronic transport properties of liquid Fe-S alloys at conditions of planetary cores, computed by first-principle techniques in the Kubo-Greenwood formalism. We describe a combined effect of resistivity saturation due to temperature, ... More
A new ab initio equation of state of hcp-Fe and its implication on the interior structure and mass-radius relations of rocky super-EarthsMay 26 2018More than a third of all exoplanets can be classified as super-Earths based on radius (1-2 $R_{\bigoplus}$) and mass (< 10 $M_{\bigoplus}$). Here we model mass-radius relations based on silicate mantle and iron core equations of state to infer to first ... More
Comment on "On the importance of the free energy for elasticity under pressure"Apr 14 2004Marcus et al. (Marcus P, Ma H and Qiu S L 2002 J. Phys.: Condens. Matter 14 L525) claim that thermodynamic properties of materials under pressure must be computed using the Gibbs free energy $G$, rather than the internal energy $E$. Marcus et al. state ... More
Evidence of local magnetic order in hcp iron from Raman mode splittingNov 26 2001Experimental measurements of Raman spectra for hcp iron at high pressure show two modes over a considerable pressure range in contrast to the prediction of one doubly degenerate mode for the hcp lattice. We use density functional theory to investigate ... More
Physical Properties of Iron in the Inner CoreApr 18 2002The Earth's inner core plays a vital role in the dynamics of our planet and is itself strongly exposed to dynamic processes as evidenced by a complex pattern of elastic structure. To gain deeper insight into the nature of these processes we rely on a ... More
Absence of lattice strain anomalies at the electronic topological transition in zinc at high pressureMay 30 2000Oct 16 2000High pressure structural distortions of the hexagonal close packed (hcp) element zinc have been a subject of controversy. Earlier experimental results and theory showed a large anomaly in lattice strain with compression in zinc at about 10 GPa which was ... More
Spontaneous charge carrier localization in extended one-dimensional systemsSep 17 2015Jan 12 2016Charge carrier localization in extended atomic systems has been described previously as being driven by disorder, point defects or distortions of the ionic lattice. Here we show for the first time by means of first-principles computations that charge ... More
Deviations from piecewise linearity in the solid-state limit with approximate density functionalsSep 16 2014In exact density functional theory (DFT) the total ground-state energy is a series of linear segments between integer electron points, a condition known as "piecewise linearity". Deviation from this condition is indicative of poor predictive capabilities ... More
Pressure induced Hydrogen-Hydrogen interaction in metallic FeH revealed by NMRFeb 08 2019Knowledge of the behavior of hydrogen in metal hydrides is the key for understanding their electronic properties. So far, no experimental methods exist to access these properties beyond 100 GPa, where high-Tc superconductivity emerges. Here, we present ... More
Search for fast correlated X-ray and optical variability in Cir X-1 and XTE J1746-321Apr 27 2004Apr 29 2004Coordinated observations X-ray+optical observations of two southern X-ray binaries, the black hole candidate XTE J1746-321 and the neutron star accreter Cir X-1 (a `microquasar') are reported. With a photon counting optical photometer on the 1.9m telescope ... More
Applying Explanation-based Learning to Control and Speeding-up Natural Language GenerationDec 08 1997This paper presents a method for the automatic extraction of subgrammars to control and speeding-up natural language generation NLG. The method is based on explanation-based learning (EBL). The main advantage for the proposed new method for NLG is that ... More
Defence Against the Modern Arts: the Curse of Statistics -- FRStatAug 04 2019For several decades, legal and scientific scholars have argued that conclusions from forensic examinations should be supported by statistical data and reported within a probabilistic framework. Multiple models have been proposed to quantify the probative ... More
Recent Developments in Gluon Fusion Higgs CalculationsOct 03 2018During recent years perturbative fixed order and resummation calculations have decreased uncertainties on predictions for gluon fusion Higgs production cross sections tremendously. Most exciting results have been published just this year. In these proceedings ... More
Regularity in $L_p$ Sobolev spaces of solutions to fractional heat equationsJun 19 2017Jan 01 2018This work contributes in two areas, with sharp results, to the current investigation of regularity of solutions of heat equations (*) $Pu+\partial_tu=f$ on $\Omega\times I $, where $P$ is a nonlocal operator, and $\Omega \subset R^n$, $I\subset R$. 1) ... More
Krein-like extensions and the lower boundedness problem for elliptic operatorsFeb 24 2010Sep 29 2011For selfadjoint extensions tilde-A of a symmetric densely defined positive operator A_min, the lower boundedness problem is the question of whether tilde-A is lower bounded {\it if and only if} an associated operator T in abstract boundary spaces is lower ... More
Spectral asymptotics for Robin problems with a discontinuous coefficientSep 06 2010Jan 27 2011The spectral behavior of the difference between the resolvents of two realizations $\tilde A_1$ and $\tilde A_2$ of a second-order strongly elliptic symmetric differential operator $A$, defined by different Robin conditions $\nu u=b_1\gamma_0u$ and $\nu ... More
Computation of the first Chow group of a Hilbert scheme of space curvesMar 01 2011Jun 20 2014An earlier wrong formula for the dimension of the first Chow group of a Hilbert scheme of space curves is corrected.
A universal definition of the Kondo energy from the orthogonality catastropheJan 21 2010The definitions of the Kondo energy in the numerical renormalization group (NRG) and the Friedel artificially inserted resonance (FAIR) theory fail sadly for small samples where their predicted Kondo energy increases, while in reality the Kondo effect ... More
Conditional expectations associated with quantum statesJan 21 2010An extension of the conditional expectations (those under a given subalgebra of events and not the simple ones under a single event) from the classical to the quantum case is presented. In the classical case, the conditional expectations always exist; ... More
Delta-Interference of Two Friedel ResonancesDec 05 2009When a single resonator is coupled to a continuous spectrum one obtains a resonance of finite half-width. Such a resonance is known in many fields of physics. The Friedel resonance is an example where a d-impurity is dissolved in a simple metal. If two ... More
Quantum teleportation and Grover's algorithm without the wavefunctionNov 09 2016Jan 07 2017In the same way as the quantum no-cloning theorem and quantum key distribution in two preceding papers, entanglement-assisted quantum teleportation and Grover's search algorithm are generalized by transferring them to an abstract setting, including usual ... More
Getting used to quantum opticsFeb 09 2016The article reviews how to measure one and the same photon at both output ports of a beam splitter.
The physical reality of the quantum wave functionJan 28 2015Can it possibly be that the proper interpretation of quantum theory, which allows a quantum system to be in a superposition of mutually exclusive states, is itself a superposition of seemingly contradicting interpretations?
Physical Reality and Information - Three HypothesesMar 11 2010Since its emergence, quantum mechanics has been a challenge for an understanding of reality which is based on our intuition in a classical world. Nevertheless, it has often been tried to impose this understanding of reality on quantum theory - with limited ... More
A Compact Treatment of the Friedel-Anderson and the Kondo Impurity Using the FAIR MethodAug 26 2009Although the Kondo effect and the Kondo ground state of a magnetic impurity have been investigated for more than forty years it was until recently difficult if not impossible to calculate spatial properties of the ground state. In particular the calculation ... More
The Friedel-Anderson and Kondo Impurity Problem for Arbitrary s-Band Density of States and Exchange InteractionAug 24 2007In his renormalization paper of the Kondo effect Wilson replaced the full band of s-electrons by a small number of ''Wilson states''. He started from a rather artificial symmetric band with constant density of states and constant interaction with the ... More
Logarithmic terms in trace expansions of Atiyah-Patodi-Singer problemsFeb 24 2003Mar 15 2004For a Dirac-type operator D with a spectral boundary condition, the associated heat operator trace has an expansion in powers and log-powers of t. Some of the log-coefficients vanish in the Atiyah-Patodi-Singer product case. We here investigate the effect ... More
Toda brackets and congruences of modular formsFeb 18 2011Feb 21 2011This paper investigates the relation between Toda brackets and congruences of modular forms. It determines the $f$-invariant of Toda brackets and thereby generalizes the formulas of J.F.\ Adams for the classical $e$-invariant to the chromatic second filtration. ... More
Limited regularity of solutions to fractional heat and Schrödinger equationsJun 26 2018Dec 17 2018When $P$ is the fractional Laplacian $(-\Delta )^a$, $0<a<1$, or a pseudodifferential generalization thereof, the Dirichlet problem for the associated heat equation over a smooth set $\Omega \subset{\Bbb R}^n$: $r^+Pu(x,t)+\partial_tu(x,t)=f(x,t)$ on ... More
A hierarchy of compatibility and comeasurability levels in quantum logics with unique conditional probabilitiesJan 10 2010In the quantum mechanical Hilbert space formalism, the probabilistic interpretation is a later ad-hoc add-on, more or less enforced by the experimental evidence, but not motivated by the mathematical model itself. A model involving a clear probabilistic ... More
X-ray follow-up observations of unidentified VHE gamma-ray sourcesNov 23 2008A large fraction of the recently discovered Galactic Very High Energy (VHE) source population remains unidentified to date. VHE gamma-ray emission traces high energy particles in these sources, but for example in case of hadronic processes also the gas ... More
Dynamical Correspondence in a Generalized Quantum TheoryFeb 02 2014Mar 06 2015In order to figure out why quantum physics needs the complex Hilbert space, many attempts have been made to distinguish the C*-algebras and von Neumann algebras in more general classes of abstractly defined Jordan algebras (JB- and JBW-algebras). One ... More
A Generalized Quantum TheoryFeb 02 2014Sep 28 2014In quantum mechanics, the selfadjoint Hilbert space operators play a triple role as observables, generators of the dynamical groups and statistical operators defining the mixed states. One might expect that this is typical of Hilbert space quantum mechanics, ... More
Spectral boundary conditions for generalizations of Laplace and Dirac operatorsFeb 24 2003Apr 04 2003Spectral boundary conditions for Laplace-type operators, of interest in string and brane theory, are partly Dirichlet, partly Neumann-type conditions, partitioned by a pseudodifferential projection. We give sufficient conditions for existence of associated ... More
Third-order interference and a principle of `quantumness'Mar 03 2011Are there physical, probabilistic or information-theoretic principles which characterize the quantum probabilities and distinguish them from the classical case as well as from other probability theories, or which reveal why quantum mechanics requires ... More
The local and global parts of the basic zeta coefficient for operators on manifolds with boundaryNov 28 2006Nov 13 2007For operators on a compact manifold $X$ with boundary $\partial X$, the basic zeta coefficient $C_0(B, P_{1,T})$ is the regular value at $s=0$ of the zeta function $\Tr(B P_{1,T}^{-s})$, where $B=P_++G$ is a pseudodifferential boundary operator (in the ... More
Artificial skill in monsoon onset prediction: two recent examplesJul 18 2019For two cases of empirical monsoon onset prediction it is argued that current verification practice leads to optimistically biased skill, caused by the intricacy of the model setup. For the case of the operational forecasts by the Indian Meteorological ... More
Spectral results for mixed problems and fractional elliptic operatorsJul 03 2014Jul 16 2014In the first part of the paper we show Weyl type spectral asymptotic formulas for pseudodifferential operators $P_a$ of order $2a$, with type and factorization index $a\in R_+$, restricted to compact sets with boundary; this includes fractional powers ... More
Regularity of spectral fractional Dirichlet and Neumann problemsDec 11 2014Jun 28 2015Consider the fractional powers $(A_{\operatorname{Dir}})^a$ and $(A_{\operatorname{Neu}})^a$ of the Dirichlet and Neumann realizations of a second-order strongly elliptic differential operator $A$ on a smooth bounded subset $\Omega $ of ${\Bbb R}^n$. ... More
Extension theory for elliptic partial differential operators with pseudodifferential methodsAug 05 2010Sep 15 2011This is a short survey on the connection between general extension theories and the study of realizations of elliptic operators A on smooth domains in R^n, n > 1. The theory of pseudodifferential boundary problems has turned out to be very useful here, ... More
The mixed boundary value problem, Krein resolvent formulas and spectral asymptotic estimatesApr 05 2011Apr 28 2011For a second-order symmetric strongly elliptic operator A on a smooth bounded open set \Omega in R^n with boundary \Sigma, the mixed problem is defined by a Neumann-type condition on a part Sigma_+ of the boundary and a Dirichlet condition on the other ... More
The sectorial projection defined from logarithmsFeb 20 2011Jul 26 2011For a classical elliptic pseudodifferential operator P of order m>0 on a closed manifold X, such that the eigenvalues of the principal symbol p_m(x,\xi) have arguments in \,]\theta,\phi [\, and \,]\phi, \theta +2\pi [\, (\theta <\phi <\theta +2\pi), the ... More
Green's formula for the fractional Laplacian and perturbationsApr 07 2019Let $\Omega $ be an open, smooth, bounded subset of $ \Bbb R ^n$. In connection with the fractional Laplacian $(-\Delta )^a$ ($a>0$), and more generally for a $2a$-order classical pseudodifferential operator ($\psi $do) $P$ with even symbol, one can define ... More
Integration by parts and Pohozaev identities for space-dependent fractional-order operatorsNov 12 2015Apr 18 2016Consider a classical elliptic pseudodifferential operator $P$ on ${\Bbb R}^n$ of order $2a$ ($0<a<1)$ with even symbol. For example, $P=A(x,D)^a$ where $A(x,D)$ is a second-order strongly elliptic differential operator; the fractional Laplacian $(-\Delta ... More
Analysis of Invariants Associated with Spectral Boundary Problems for an Elliptic OperatorJun 08 2004This is a survey of recent results on zeta- and eta-function poles and values for realizations of Laplace- and Dirac-type operators defined by pseudodifferential projection boundary conditions (including the Atiyah-Patodi-Singer operator and its square). ... More
A resolvent approach to traces and zeta Laurent expansionsNov 06 2003Dec 19 2005Classical pseudodifferential operators A on closed manifolds are considered. It is shown that the basic properties of the canonical trace TR A introduced by Kontsevich and Vishik are easily proved by identifying it with the leading nonlocal coefficient ... More
Green's formula and a Dirichlet-to-Neumann operator for fractional-order pseudodifferential operatorsNov 09 2016Nov 15 2016The paper treats boundary value problems for the fractional Laplacian $(-\Delta )^a$, $a>0$, and its generalizations to pseudodifferential operators ($\psi $do's) $P$ of order $2a$ with even symbol, applied to functions on a smooth subset $\Omega $ of ... More
Friedel oscillations of Kondo impurities: A comparisonMay 06 2008Recently Affleck et al. derived the existence of Friedel oscillations in the presence of a Kondo impurity. They supported their analytic derivation by numerical calculations using Wilson's renormalization approach (NRG). In this paper the size of the ... More
The Heart of FidelityJul 10 2012The multi-electron wave function of an interacting electron system depends on the size of the system, i.e. the number of electrons. Here the question investigated is how the wave function changes for a symmetric Friedel-Anderson impurity when the volume ... More
Pauli Blocking in Degenerate Plasmas and the Separable Potential ApproachJan 23 2019The Mott effect describes the dissolution of bound states in a dense partially ionized plasma. It happens when the ionization potential depression, owing to effects of correlation and degeneracy, compensates the binding energy of the bound state. At high ... More
Three-slit experiments and quantum nonlocalityApr 01 2011Apr 24 2013An interesting link between two very different physical aspects of quantum mechanics is revealed; these are the absence of third-order interference and Tsirelson's bound for the nonlocal correlations. Considering multiple-slit experiments - not only the ... More
Different Types of Conditional Expectation and the Lueders - von Neumann Quantum MeasurementJan 21 2010In operator algebra theory, a conditional expectation is usually assumed to be a projection map onto a sub-algebra. In the paper, a further type of conditional expectation and an extension of the Lueders - von Neumann measurement to observables with continuous ... More
Conditional probability, three-slit experiments, and the Jordan algebra structure of quantum mechanicsDec 01 2009Sep 30 2012Most quantum logics do not allow for a reasonable calculus of conditional probability. However, those ones which do so provide a very general and rich mathematical structure, including classical probabilities, quantum mechanics as well as Jordan algebras. ... More
How the Kondo ground state avoids the orthogonality catastropheNov 20 2008In the presence of a magnetic impurity the spin-up and down band states are modified differently by the impurity. If the multi-electron scalar product (MESP) between the occupied spin-up and down states approaches zero then this defines an orthogonality ... More
A Compact Approximate Solution to the Friedel-Anderson Impuriy ProblemFeb 08 2006An approximate groundstate of the Anderson-Friedel impurity problem is presented in a very compact form. It requires solely the optimization of two localized electron states and consists of four Slater states (Slater determinants). The resulting singlet ... More
A Critical Analysis of the Mean-Field Approximation for the Calculation of the Magnetic Moment in the Friedel-Anderson Impurity ModelAug 29 2005It is shown that the calculation of the magnetic moment of a Friedel-Anderson impurity in mean-field theory is unreliable. A class of approximate solutions, which contains the mean-field solution as an element, is expressed in rotated Hilbert space and ... More
Symmetries of Surface SingularitiesApr 24 1996The automorphism group ${\rm Aut}\: X$ of a weighted homogeneous normal surface singularity $X$ has a maximal reductive algebraic subgroup $G$ which contains every reductive algebraic subgroup of ${\rm Aut}\: X$ up to conjugation. In all cases except ... More
Quantum key distribution without the wavefunctionNov 08 2016A well-known feature of quantum mechanics is the secure exchange of secret bit strings which can then be used as keys to encrypt messages transmitted over any classical communication channel. It is demonstrated that this quantum key distribution allows ... More
Iitaka-Severi's Conjecture for Complex ThreefoldsMay 12 1995Nov 29 2014We prove the following generalization of Severi's Theorem: Let $X$ be a fixed complex variety. Then there exist, up to birational equivalence, only finitely many complex varieties $Y$ of general type of dimension at most three which admit a dominant rational ... More
Some geometric properties of Hilbert schemes of space curvesJun 20 2014May 16 2019Let $H$ be the Hilbert scheme of curves in complex projective $3$-space, with $d\geq 3$ and genus $g \leq (d-2)^2/4$. A complete, explicit description of the cone of curves and the ample cone of $H$ is given. From this, partial results on the group $\mathop{Aut}(H)$ ... More
Remarks on nonlocal trace expansion coefficientsOct 03 2005Dec 19 2005In a recent work, Paycha and Scott establish formulas for all the Laurent coefficients of Tr(AP^{-s}) at the possible poles. In particular, they show a formula for the zero'th coefficient at s=0, in terms of two functions generalizing, respectively, the ... More
Fractional-order operators: Boundary problems, heat equationsDec 04 2017Mar 02 2018The first half of this work gives a survey of the fractional Laplacian (and related operators), its restricted Dirichlet realization on a bounded domain, and its nonhomogeneous local boundary conditions, as treated by pseudodifferential methods. The second ... More
Spectral asymptotics for nonsmooth singular Green operatorsMay 01 2012Jun 28 2013Singular Green operators G appear typically as boundary correction terms in resolvents for elliptic boundary value problems on a domain \Omega \subset R^n, and more generally they appear in the calculus of pseudodifferential boundary problems. In particular, ... More
Perturbation of essential spectra of exterior elliptic problemsNov 11 2008Nov 17 2009For a second-order strongly elliptic differential operator on an exterior domain in R^n it is known from works of Birman and Solomiak that a change of the boundary condition from the Dirichlet condition to an elliptic Neumann or Robin condition leaves ... More
Krein resolvent formulas for elliptic boundary problems in nonsmooth domainsOct 15 2008The paper reports on a recent construction of M-functions and Krein resolvent formulas for general closed extensions of an adjoint pair, and their implementation to boundary value problems for second-order strongly elliptic operators on smooth domains. ... More
Importance of Magnetism in Phase Stability, Equations of State, and ElasticityOct 01 2001Jul 24 2002The effects of magnetism on high pressure properties of transition metals and transition metal compounds can be quite important. In the case of Fe, magnetism is responsible for stability of the body-centered cubic (bcc) phase at ambient conditions, and ... More
First-Principles Elastic Constants for the hcp Transition Metals Fe, Co, and Re at High PressureApr 29 1999The elastic constant tensors for the hcp phases of three transition metals (Co, Re, and Fe) are computed as functions of pressure using the Linearized Augmented Plane Wave method with both the local density and generalized gradient approximations. Spin-polarized ... More
New optical polarization measurements of the Crab pulsarNov 21 2005The Crab nebula and its pulsar have been observed for about 3 hours with the high-speed photo-polarimeter OPTIMA in January 2002 at the Calar Alto 3.5m telescope. The Crab pulsar intensity and polarization are determined at all phases of rotation with ... More
Evolutionary Image Transition Based on Theoretical Insights of Random ProcessesApr 21 2016Evolutionary algorithms have been widely studied from a theoretical perspective. In particular, the area of runtime analysis has contributed significantly to a theoretical understanding and provided insights into the working behaviour of these algorithms. ... More
Quasi-random Agents for Image Transition and AnimationOct 20 2017Quasi-random walks show similar features as standard random walks, but with much less randomness. We utilize this established model from discrete mathematics and show how agents carrying out quasi-random walks can be used for image transition and animation. ... More
On Leighton's graph covering theoremJun 13 2009May 25 2010We give short expositions of both Leighton's proof and the Bass-Kulkarni proof of Leighton's graph covering theorem, in the context of colored graphs. We discuss a further generalization, needed elsewhere, to "symmetry-restricted graphs." We can prove ... More
Large deviations for the exclusion process with a slow bondJan 01 2015Feb 07 2017We consider the one-dimensional symmetric simple exclusion process with a slow bond. In this model, whilst all the transition rates are equal to one, a particular bond, the \emph{slow bond}, has associated transition rate of value $N^{-1}$, where $N$ ... More
Proof of the Ergodic Theorem and the H-Theorem in Quantum MechanicsMar 10 2010Sep 02 2010It is shown how to resolve the apparent contradiction between the macroscopic approach of phase space and the validity of the uncertainty relations. The main notions of statistical mechanics are re-interpreted in a quantum-mechanical way, the ergodic ... More
Computational Complexity Results for Genetic Programming and the Sorting ProblemMar 29 2011May 06 2011Genetic Programming (GP) has found various applications. Understanding this type of algorithm from a theoretical point of view is a challenging task. The first results on the computational complexity of GP have been obtained for problems with isolated ... More
On the Runtime of Randomized Local Search and Simple Evolutionary Algorithms for Dynamic Makespan SchedulingApr 23 2015Evolutionary algorithms have been frequently used for dynamic optimization problems. With this paper, we contribute to the theoretical understanding of this research area. We present the first computational complexity analysis of evolutionary algorithms ... More
Comment on "New formulas for the (-2) moment of the photoabsorption cross section, σ_(-2)"Jul 05 2015Mar 08 2016Empirical formulas for the second inverse moment of the photoabsorption cross sections in nuclei are discussed in J. N. Orce, Phys. Rev. C 91, 064602 (2015). In this Comment I point out that the experimental values used are systematically too small in ... More
Absolute regularity and ergodicity of Poisson count processesJan 05 2012We consider a class of observation-driven Poisson count processes where the current value of the accompanying intensity process depends on previous values of both processes. We show under a contractive condition that the bivariate process has a unique ... More
Étale homotopy types of moduli stacks of polarised abelian schemesDec 23 2015We determine the Artin-Mazur \'etale homotopy types of moduli stacks of polarised abelian schemes using transcendental methods and derive some arithmetic properties of the \'etale fundamental groups of these moduli stacks. Finally we analyse the Torelli ... More
Tradable SchemesSep 04 2000In this article we present a new approach to the numerical valuation of derivative securities. The method is based on our previous work where we formulated the theory of pricing in terms of tradables. The basic idea is to fit a finite difference scheme ... More
Tracing the X-ray emitting intra-cluster medium of clusters of galaxies beyond r_200May 03 2005(Abridged) We present in this paper a sample of 14 nearby clusters of galaxies observed with the ROSAT/PSPC. We only select clusters with low galactic nH in order to trace the X-ray emitting intra-cluster medium (ICM) out to large radii. We convert the ... More
Regular geodesic normal forms in virtually abelian groupsFeb 24 1997Cannon has given an example of a virtually abelian group and a generating set where the full language of geodesics is not regular. We describe a virtually abelian group and a generating set so that no regular language of geodesics surjects to the group. ... More
A characterization of shortest geodesics on surfacesJun 24 2001Any finite configuration of curves with minimal intersections on a surface is a configuration of shortest geodesics for some Riemannian metric on the surface. The metric can be chosen to make the lengths of these geodesics equal to the number of intersections ... More
Deconvolution of dust mixtures by latent Dirichlet allocation in forensic scienceMay 16 2018Jan 31 2019Dust particles recovered from the soles of shoes may be indicative of the sites recently visited by an individual, and, in particular, of the presence of an individual at a particular site of interest, e.g., the scene of a crime. By describing the dust ... More
This House Proves that Debating is Harder than SoccerMay 10 2016During the last twenty years, a lot of research was conducted on the sport elimination problem: Given a sports league and its remaining matches, we have to decide whether a given team can still possibly win the competition, i.e., place first in the league ... More
Kleinian Groups Generated by RotationsDec 04 1997We discuss which Kleinian groups are commensurable with Kleinian groups generated by rotations, with particular emphasis on Kleinian groups that arise from Dehn surgery on a knot.
Central Extensions of Word Hyperbolic GroupsJul 13 1995Thurston has claimed (unpublished) that central extensions of word hyperbolic groups by finitely generated abelian groups are automatic. We show that they are in fact biautomatic. Further, we show that every 2-dimensional cohomology class on a word hyperbolic ... More
Scaling invariance in finance II: Path-dependent contingent claimsJul 13 1999This article is the second one in a series on the use of scaling invariance in finance. In the first article (cond-mat/9906048), we introduced a new formalism for the pricing of derivative securities, which focusses on tradable objects only, and which ... More
Molecular association at the microscopic levelMar 12 2005The Helmholtz free-energy W is calculated as a function of separation distance for two molecules in a fluid, A and B, whose mutual interaction is described by a spherically symmetric potential. For the equilibrium A + B = AB occurring in a dilute solution ... More
Parametrised second-order complexity theory with applications to the study of interval computationNov 28 2017We extend the framework for complexity of operators in analysis devised by Kawamura and Cook (2012) to allow for the treatment of a wider class of representations. The main novelty is to endow represented spaces of interest with an additional function ... More
Parametrised second-order complexity theory with applications to the study of interval computationNov 28 2017Jun 12 2019We extend the framework for complexity of operators in analysis devised by Kawamura and Cook (2012) to allow for the treatment of a wider class of representations. The main novelty is to endow represented spaces of interest with an additional function ... More
Hilbert's 3rd Problem and invariants of 3-manifoldsDec 04 1997Oct 27 1998This paper is an expansion of my lecture for David Epstein's birthday, which traced a logical progression from ideas of Euclid on subdividing polygons to some recent research on invariants of hyperbolic 3-manifolds. This `logical progression' makes a ... More
Moduli Stacks of Vector Bundles and Frobenius MorphismsApr 23 2004We describe the action of the different Frobenius morphisms on the cohomology ring of the moduli stack of algebraic vector bundles of fixed rank and determinant on an algebraic curve over a finite field in characteristic p and analyse special situations ... More
Spectral sequences for Hochschild cohomology and graded centers of derived categoriesMar 31 2016The Hochschild cohomology of a differential graded algebra, or differential graded category, admits a natural map to the graded center of its derived category: the characteristic homomorphism. We interpret it as an edge homomorphism in a spectral sequence. ... More
A topological view on algebraic computation modelsFeb 25 2016We investigate the topological aspects of some algebraic computation models, in particular the BSS-model. Our results can be seen as bounds on how different BSS-computability and computability in the sense of computable analysis can be. The framework ... More
The Packing While Traveling ProblemDec 30 2015This paper introduces the Packing While Traveling problem as a new non-linear knapsack problem. Given are a set of cities that have a set of items of distinct profits and weights and a vehicle that may collect the items when visiting all the cities in ... More
Ideal-Chain Collapse in BiopolymersNov 29 2000Dec 18 2000A conceptual difficulty in the Hooke's-law description of ideal Gaussian polymer-chain elasticity is sometimes apparent in analyses of experimental data or in physical models designed to simulate the behavior of biopolymers. The problem, the tendency ... More
Phase Diagram for Unzipping DNA Using a Bond-Force CriterionJan 29 2002Using the criterion that the mechanical unzipping transition in a bound homopolymer is triggered when the average force exerted by the single unbound strands on the first base pair in the bound section exceeds the force binding the pair together, the ... More
Representations and evaluation strategies for feasibly approximable functionsOct 10 2017Nov 09 2018A famous result due to Ko and Friedman (1982) asserts that the problems of integration and maximisation of a univariate real function are computationally hard in a well-defined sense. Yet, both functionals are routinely computed at great speed in practice. ... More
The Packing While Traveling ProblemDec 30 2015Mar 21 2017This paper introduces the Packing While Traveling problem as a new non-linear knapsack problem. Given are a set of cities that have a set of items of distinct profits and weights and a vehicle that may collect the items when visiting all the cities in ... More
Atiyah sequences, connections and Chern-Weil theory for algebraic and differentiable stacksNov 19 2013Nov 26 2013We construct connections and characteristic forms for principal bundles over groupoids and stacks in the differentiable, holomorphic and algebraic category using Atiyah sequences associated to transversal tangential distributions.