Results for "Jakob Schiøtz"

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Quantum corrected Langevin dynamics for adsorbates on metal surfaces interacting with hot electronsMar 11 2010We investigate the importance of including quantized initial conditions in Langevin dynamics for adsorbates interacting with a thermal reservoir of electrons. For quadratic potentials the time evolution is exactly described by a classical Langevin equation ... More
Memory effects in non-adiabatic molecular dynamics at metal surfacesJun 11 2010We study the effect of temporal correlation in a Langevin equation describing non-adiabatic dynamics at metal surfaces. For a harmonic oscillator the Langevin equation preserves the quantum dynamics exactly and it is demonstrated that memory effects are ... More
Origin of power laws for reactions at metal surfaces mediated by hot electronsNov 10 2009Dec 01 2009A wide range of experiments have established that certain chemical reactions at metal surfaces can be driven by multiple hot electron mediated excitations of adsorbates. A high transient density of hot electrons is obtained by means of femtosecond laser ... More
Vibrationally Mediated Control of Single Electron Transmission in Weakly Coupled Molecule-Metal JunctionsJan 04 2010Mar 25 2010We propose a mechanism which allows one to control the transmission of single electrons through a molecular junction. The principle utilizes the emergence of transmission sidebands when molecular vibrational modes are coupled to the electronic state mediating ... More
Robust Structural Identification via Polyhedral Template MatchingMar 16 2016Apr 18 2016Successful scientific applications of large-scale molecular dynamics often rely on automated methods for identifying the local crystalline structure of condensed phases. Many existing methods for structural identification, such as Common Neighbour Analysis, ... More
Electrochemical control of quantum interference in anthraquinone-based molecular switchesMay 04 2010Using first-principles calculations we analyze the electronic transport properties of a recently proposed anthraquinone based electrochemical switch. Robust conductance on/off ratios of several orders of magnitude are observed due to destructive quantum ... More
Hot electron mediated desorption rates calculated from excited state potential energy surfacesOct 15 2008Jan 07 2009We present a model for Desorption Induce by (Multiple) Electronic Transitions (DIET/DIMET) based on potential energy surfaces calculated with the Delta Self-Consistent Field extension of Density Functional Theory. We calculate potential energy surfaces ... More
Microscopic Calculation of Flow Stress in Cu-Mg Metallic GlassJun 14 2004We have carried out shear-deformation simulations on amorphous Mg-Cu systems at zero temperature and pressure, containing 2048-131072 atoms. At the largest size a smooth stress-strain curve is obtained with a well-defined flow stress. In the smallest ... More
Delta Self-Consistent Field as a method to obtain potential energy surfaces of excited molecules on surfacesJul 21 2008We present a modification of the $\Delta$SCF method of calculating energies of excited states, in order to make it applicable to resonance calculations of molecules adsorbed on metal surfaces, where the molecular orbitals are highly hybridized. The $\Delta$SCF ... More
Simulation of Cu-Mg metallic glass: Thermodynamics and StructureSep 29 2003We have obtained effective medium theory (EMT) interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced ... More
A deep learning approach to identify local structures in atomic-resolution transmission electron microscopy imagesFeb 08 2018Recording atomic-resolution transmission electron microscopy (TEM) images is becoming increasingly routine. A new bottleneck is then analyzing this information, which often involves time-consuming manual structural identification. We have developed a ... More
Modelling of dislocation generation and interaction during high-speed deformation of metalsAug 23 2000Recent experiments by Kiritani et al. have revealed a surprisingly high rate of vacancy production during high-speed deformation of thin foils of fcc metals. Virtually no dislocations are seen after the deformation. This is interpreted as evidence for ... More
Dislocation nucleation and vacancy formation during high-speed deformation of fcc metalsSep 27 2000Mar 12 2001Recently, a dislocation free deformation mechanism was proposed by Kiritani et al., based on a series of experiments where thin foils of fcc metals were deformed at very high strain rates. In the experimental study, they observed a large density of stacking ... More
Effect of Crack Blunting on Subsequent Crack PropagationDec 06 1995Theories of toughness of materials depend on an understanding of the characteristic instabilities of the crack tip, and their possible interactions. In this paper we examine the effect of dislocation emission on subsequent cleavage of a crack and on further ... More
Arakelov motivic cohomology IIMay 17 2012Oct 19 2013We show that the constructions done in part I generalize their classical counterparts: firstly, the classical Beilinson regulator is induced by the abstract Chern class map from $BGL$ to the Deligne cohomology spectrum. Secondly, Arakelov motivic cohomology ... More
Unifying N=5 and N=6Mar 24 2011Jul 10 2011We write the Lagrangian of the general N=5 three-dimensional superconformal Chern-Simons theory, based on a basic Lie superalgebra, in terms of our recently introduced N=5 three-algebras. These include N=6 and N=8 three-algebras as special cases. When ... More
Mixed Artin-Tate motives over number ringsMar 05 2010Aug 05 2010This paper studies Artin-Tate motives over number rings. As a subcategory of geometric motives, the triangulated category of Artin-Tate motives DATM(S) is generated by motives of schemes that are finite over the base S. After establishing stability of ... More
Uniform central limit theorems for the Grenander estimatorNov 24 2014Jun 26 2015We consider the Grenander estimator that is the maximum likelihood estimator for non-increasing densities. We prove uniform central limit theorems for certain subclasses of bounded variation functions and for H\"older balls of smoothness s>1/2. We do ... More
Non-elementary proper forcingOct 12 2009May 08 2011We introduce a simplified framework for ord-transitive models and Shelah's non elementary proper (nep) theory. We also introduce a new construction for the countable support nep iteration.
Discovering and Proving Infinite Binomial Sums IdentitiesJul 07 2015Oct 29 2015We consider binomial and inverse binomial sums at infinity and rewrite them in terms of a small set of constants, such as powers of $\pi$ or $\log(2)$. In order to perform these simplifications, we view the series as specializations of generating series. ... More
On the 3-torsion Part of the Homology of the Chessboard ComplexMar 26 2012Let $1 \le m \le n$. We prove various results about the chessboard complex $M_{m,n}$, which is the simplicial complex of matchings in the complete bipartite graph $K_{m,n}$. First, we demonstrate that there is nonvanishing 3-torsion in $H_d(M_{m,n};Z)$ ... More
Exceptional geometry and Borcherds superalgebrasJul 31 2015Jun 20 2016We study generalized diffeomorphisms in exceptional geometry with U-duality group E_{n(n)} from an algebraic point of view. By extending the Lie algebra e_n to an infinite-dimensional Borcherds superalgebra, involving also the extension to e_{n+1}, the ... More
Permanental Point Processes on Real Tori, Theta Functions and Monge-Ampère EquationsApr 19 2016May 18 2016Inspired by constructions in complex geometry we introduce a thermodynamic framework for Monge-Amp\`ere equations on real tori. We show convergence in law of the associated point processes and explain connections to complex Monge-Amp\`ere equations and ... More
On the birational section conjecture with local conditionsMar 14 2012Sep 17 2015A birationally liftable Galois section s of a hyperbolic curve X/k over a number field k yields an adelic point x(s) in the smooth completion of X. We show that x(s) is X-integral outside a set of places of Dirichlet density 0, or s is cuspidal. The proof ... More
The Brauer-Manin obstruction for sections of the fundamental groupOct 26 2009We establish Grothendieck's section conjecture for an open subset of the Reichardt-Lind curve, and introduce the notion of a Brauer-Manin obstruction for sections of the fundamental group extension.
A monodromy criterion for extending curvesAug 23 2004Nov 10 2004A family of proper smooth curves of genus $\geq 2$, parametrised by an open dense subset $U$ of a normal variety $S$, extends to $S$ if the natural map $\pi_1(U) \to \pi_1(S)$ on fundamental groups is an isomorphism. The criterion of this note is actually ... More
Affine anabelian curves in positive characteristicJun 18 2002An investigation of morphisms that coincide topologically is used to generalize to all characteristics and partly reprove Tamagawa's theorem on the Grothendieck conjecture in anabelian geometry for affine hyperbolic curves. The theorem now deals with ... More
The Role of Type III Factors in Quantum Field TheoryNov 17 2004Dec 04 2004One of von Neumann's motivations for developing the theory of operator algebras and his and Murray's 1936 classification of factors was the question of possible decompositions of quantum systems into independent parts. For quantum systems with a finite ... More
A logarithmic view towards semistable reductionMay 18 2003The geometric condition of T. Saito for trivial action of the wild monodromy of a smooth proper curve over the generic point of a trait is transformed to the condition of logarithmic smooth reduction. The proof emphasizes methods and results from logarithmic ... More
Five-Torsion in the Homology of the Matching Complex on 14 VerticesMar 26 2012J. L. Andersen proved that there is 5-torsion in the bottom nonvanishing homology group of the simplicial complex of graphs of degree at most two on seven vertices. We use this result to demonstrate that there is 5-torsion also in the bottom nonvanishing ... More
Exact Sequences for the Homology of the Matching ComplexMar 26 2012Building on work by Bouc and by Shareshian and Wachs, we provide a toolbox of long exact sequences for the reduced simplicial homology of the matching complex $M_n$, which is the simplicial complex of matchings in the complete graph $K_n$. Combining these ... More
On the graph-theoretical interpretation of Pearson correlations in a multivariate process and a novel partial correlation measureOct 18 2013The dependencies of the lagged (Pearson) correlation function on the coefficients of multivariate autoregressive models are interpreted in the framework of time series graphs. Time series graphs are related to the concept of Granger causality and encode ... More
Atomic-scale simulations of nanocrystalline metalsFeb 11 1999Nanocrystalline metals, i.e. metals in which the grain size is in the nanometer range, have a range of technologically interesting properties including increased hardness and yield strength. We present atomic-scale simulations of the plastic behavior ... More
Connecting generalized parton distributions and light-cone wave functionsSep 26 2000The relation of generalized (skewed) quark distributions to nucleon wave functions is discussed in the context of light-cone quantization.
Wide Angle Compton ScatteringOct 16 2000We present the handbag contribution to Wide Angle Compton Scattering (WACS) at moderately large momentum transfer obtained with a proton distribution amplitude close to the asymptotic form. In comparison it is found to be significantly larger than results ... More
Proton-Proton Elastic Scattering; Landshoff Contributions in the Diquark ModelJun 08 1994Independent multiple scattering (`Landshoff') contributions to proton-proton elastic scattering at wide angles are calculated in the quark-diquark model. Results confirm previous observations about the magnitude of these contributions. The use of the ... More
A note on the Thom isomorphism in geometric (co)homologyMar 31 2004Using geometric homology and cohomology we give a simple and conceptual proof of the Thom isomorphism theorem.
On the period-index problem in light of the section conjectureFeb 28 2008Period and index of a curve $X/K$ over a $p$-adic local field $K$ such that the fundamental group $\pi_1(X/K)$ admits a splitting are shown to be powers of $p$. As a consequence, examples of curves over number fields are constructed where having sections ... More
More Torsion in the Homology of the Matching ComplexMar 26 2012Mar 28 2012A matching on a set $X$ is a collection of pairwise disjoint subsets of $X$ of size two. Using computers, we analyze the integral homology of the matching complex $M_n$, which is the simplicial complex of matchings on the set $\{1, >..., n\}$. The main ... More
Topics in the Mathematical Physics of Cold Bose GasesFeb 04 2014Feb 14 2014In these notes of six lectures on selected topics in the theory of cold, dilute Bose gases, presented at the 5th Warsaw School of Statistical Physics in June 2013, the following topics are discussed: 1) The concept of BEC, 2) the ground state energy of ... More
Trading degree for dimension in the section conjecture: The non-abelian Shapiro LemmaFeb 10 2009This note aims at providing evidence for the section conjecture of anabelian geometry by establishing its behaviour under Weil restriction of scalars. In particular, the etale fundamental group of the Weil restriction is determined by means of a Shapiro ... More
On cuspidal sections of algebraic fundamental groupsAug 29 2008Rational points in the boundary of a hyperbolic curve over a field with sufficiently nontrivial Kummer theory are the source for an abundance of sections of the fundamental group exact sequence. We follow and refine Nakamura's approach towards these boundary ... More
On some Hermite series identities and their applications to Gabor analysisNov 30 2015We prove some infinite series identities for the Hermite functions. From these identities we disprove the Gabor frame set conjecture for Hermite functions of order $4m+2$ and $4m+3$ for $m \in \{0\} \cup \mathbb{N}$. The results hold not only for Hermite ... More
Ab initio van der Waals interactions in simulations of water alter structure from mainly tetrahedral to high-density-likeJan 29 2011May 03 2011The structure of liquid water at ambient conditions is studied in ab initio molecular dynamics simulations using van der Waals (vdW) density-functional theory, i.e. using the new exchange-correlation functionals optPBE-vdW and vdW-DF2. Inclusion of the ... More
Physics at the LHC -- From Standard Model measurements to Searches for New PhysicsJun 29 2012The successful operation of the {\em Large Hadron Collider} (LHC) during the past two years allowed to explore particle interaction in a new energy regime. Measurements of important Standard Model processes like the production of high-\pt\ jets, $W$ and ... More
Spin-dependent Fragmentation FunctionsJun 26 2002I will give an overview on fragmentation functions with particular emphasis on spin-dependence. A straightforward classification scheme permits to label all independent fragmentation functions for a given physical situation in an unambiguous way. In the ... More
SST polarization model and polarimeter calibrationOct 20 2010A telescope polarization model for the SST [Swedish 1-m Solar Telescope] is developed and the parameters of this model are fitted to polarization measurements made with a 1-meter linear polarizer in front of the entrance window. In this model, the 1-meter ... More
Three-algebras, triple systems and 3-graded Lie superalgebrasMay 15 2009Dec 08 2009The three-algebras used by Bagger and Lambert in N=6 theories of ABJM type are in one-to-one correspondence with a certain type of Lie superalgebras. We show that the description of three-algebras as generalized Jordan triple systems naturally leads to ... More
Simple transitive $2$-representations of Soergel bimodules in type $B_2$Sep 04 2015Jun 17 2016We prove that every simple transitive $2$-representation of the fiat $2$-category of Soergel bimodules (over the coinvariant algebra) in type $B_2$ is equivalent to a cell $2$-representation. We also describe some general properties of the $2$-category ... More
Pitowsky's Kolmogorovian models and Super-DeterminismJun 22 2016Sep 28 2016In an attempt to demonstrate that local hidden variables are mathematically possible, Pitowsky constructed "spin-$\frac12$ functions" and later "Kolmogorovian models", which employs a nonstandard notion of probability. We describe Pitowsky's analysis ... More
Stability of position control of traveling waves in reaction-diffusion systemsDec 30 2013We consider the stability of position control of traveling waves in reaction-diffusion system as proposed in {[}J. L\"ober, H. Engel, arXiv:1304.2327{]}. Instead of analyzing the controlled reaction-diffusion system, stability is studied on the reduced ... More
Birational p-adic Galois sections in higher dimensionsFeb 13 2012This note explores the consequences of Koenigsmann's model theoretic argument from the proof of the birational p-adic section conjecture for curves in the context of higher dimensional varieties over p-adic local fields.
Confidence sets in nonparametric calibration of exponential Lévy modelsFeb 29 2012Sep 19 2013Confidence intervals and joint confidence sets are constructed for the nonparametric calibration of exponential L\'evy models based on prices of European options. To this end, we show joint asymptotic normality in the spectral calibration method for the ... More
Symmetry Groups of Principal Bundles Over Non-Compact BasesOct 31 2013Nov 06 2013In this work, we describe how to obtain the structure of an infinite-dimensional Lie group on the group of compactly carried bundle automorphisms Autc(P) for a locally convex prinicpal bundle P over a finite-dimensional smooth sigma-compact base M. This ... More
Polar sets of anisotropic Gaussian random fieldsAug 03 2012This paper studies polar sets of anisotropic Gaussian random fields, i.e. sets which a Gaussian random field does not hit almost surely. The main assumptions are that the eigenvalues of the covariance matrix are bounded from below and that the canonical ... More
Simulations of mechanics and structure of nanomaterials --- from nanoscale to coarser scalesAug 19 1998We discuss how simulations of mechanical properties of materials require descriptions at many different length scales --- from the nanoscale where an atomic description is appropriate, through a mesoscale where dislocation based descriptions may be useful, ... More
Higgs Boson Searches at Hadron CollidersApr 13 2005The investigation of the dynamics responsible for electroweak symmetry breaking is one of the prime tasks of experiments at present and future colliders. Experiments at the Tevatron ppbar Collider and at the CERN Large Hadron Collider (LHC) must be able ... More
Convolutional Neural FabricsJun 08 2016Jun 09 2016Despite the success of convolutional neural networks, selecting the optimal architecture for a given task remains an open problem. Instead of aiming to select a single optimal architecture, we propose a $"$fabric$"$ that embeds an exponentially large ... More
Asymptotic Exactness of Magnetic Thomas-Fermi TheoryAug 24 2003We consider the grand canonical pressure for Coulombic matter with nuclear charges $\sim Z$ in a magnetic field $B$ and at nonzero temperature. We prove that its asymptotic limit as $Z\to\infty$ with $B/Z^3\to 0$ can be obtained by minimizing a Thomas-Fermi ... More
Quantitative conditional quantum erasure in two-atom resonance fluorescenceJun 28 2002Nov 20 2002We present a conditional quantum eraser which erases the a priori knowledge or the predictability of the path a photon takes in a Young-type double-slit experiment with two fluorescent four-level atoms. This erasure violates a recently derived erasure ... More
Breakdown of fiber bundles with stochastic load-redistributionMar 10 2010We study fracture processes within a stochastic fiber-bundle model where it is assumed that after the failure of a fiber, each intact fiber obtains a random fraction of the failing load. Within a Markov approximation, the breakdown properties of this ... More
The pion form factor: Sudakov suppressions and intrinsic transverse momentumJun 11 1993It is demonstrated that any attempt to calculate the perturbative QCD contribution to the pion form factor requires the inclusion of intrinsic transverse momentum besides Sudakov form factors. For momentum transfers of the order of a few GeV the intrinsic ... More
Spontaneous decay of resonant energy levels for molecules with moving nucleiSep 02 2011Mar 21 2012We consider the Pauli-Fierz Hamiltonian with dynamical nuclei and investigate the transitions between the resonant electronic energy levels under the assumption that there are no free photons in the beginning. Coupling the limits of small fine structure ... More
Constrained Quantum Systems as an Adiabatic ProblemMay 11 2010We derive the effective Hamiltonian for a quantum system constrained to a submanifold (the constraint manifold) of configuration space (the ambient space) in the asymptotic limit where the restoring forces tend to infinity. In contrast to earlier works ... More
Effective Hamiltonians for Constrained Quantum SystemsJul 02 2009Dec 10 2009We consider the time-dependent Schr\"odinger equation on a Riemannian manifold $\mathcal{A}$ with a potential that localizes a certain class of states close to a fixed submanifold $\mathcal{C}$. When we scale the potential in the directions normal to ... More
On Minimal Unsatisfiability and Time-Space Trade-offs for k-DNF ResolutionOct 16 2009Oct 16 2009In the context of proving lower bounds on proof space in k-DNF resolution, [Ben-Sasson and Nordstrom 2009] introduced the concept of minimally unsatisfiable sets of k-DNF formulas and proved that a minimally unsatisfiable k-DNF set with m formulas can ... More
A Sacks Real out of NowhereMar 11 2007Apr 29 2009There is a proper countable support iteration of length $\omega$ adding no new reals at finite stages and adding a Sacks real in the limit.
Convolutional Neural FabricsJun 08 2016Oct 28 2016Despite the success of CNNs, selecting the optimal architecture for a given task remains an open problem. Instead of aiming to select a single optimal architecture, we propose a "fabric" that embeds an exponentially large number of architectures. The ... More
Controlling the position of traveling waves in reaction-diffusion systemsApr 08 2013Jan 17 2014We present a method to control the position as a function of time of one-dimensional traveling wave solutions to reaction-diffusion systems according to a pre-specified protocol of motion. Given this protocol, the control function is found as the solution ... More
Detecting regime switches in the dependence structure of high dimensional financial dataFeb 09 2012Misperceptions about extreme dependencies between different financial assets have been an im- portant element of the recent financial crisis. This paper studies inhomogeneity in dependence structures using Markov switching regular vine copulas. These ... More
Wavelets for non-expanding dilations and the lattice counting estimateJan 26 2016We show that problems of existence and characterization of wavelets for non-expanding dilations are intimately connected with the geometry of numbers; more specifically, with a bound on the number of lattice points in balls dilated by the powers of a ... More
Nonparametric Bayesian posterior contraction rates for discretely observed scalar diffusionsOct 19 2015Mar 29 2016We consider nonparametric Bayesian inference in a reflected diffusion model $dX_t = b (X_t)dt + \sigma(X_t) dW_t,$ with discretely sampled observations $X_0, X_\Delta, \dots, X_{n\Delta}$. We analyse the nonlinear inverse problem corresponding to the ... More
Non-equilibrium steady states of stochastic processes with intermittent resettingOct 27 2015Stochastic processes that are randomly reset to an initial condition serve as a showcase to investigate non-equilibrium steady states. However, all existing results have been restricted to the special case of memoryless resetting protocols. Here, we obtain ... More
Weil-Châtelet divisible elements in Tate-Shafarevich groups I: The Bashmakov problem for elliptic curves over QJun 21 2011Aug 21 2013For an abelian variety A over a number field k we discuss the maximal divisibile subgroup of H^1(k,A) and its intersection with the subgroup Sha(A/k). The results are most complete for elliptic curves over Q.
Noise Fit, Estimation Error and a Sharpe Information CriterionFeb 19 2016When optimizing the Sharpe ratio over a k-dimensional parameter space the thus obtained in-sample Sharpe ratio tends to be higher than what will be captured out-of-sample. For two reasons: the estimated parameter will be skewed towards the noise in the ... More
Oxidizing Borcherds symmetriesJan 07 2013The tensor hierarchy of maximal supergravity in D dimensions is known to be closely related to a Borcherds (super)algebra that is constructed from the global symmetry group E(11-D). We here explain how the Borcherds algebras in different dimensions are ... More
K-theory for algebras of operators on Banach spacesJan 23 1997It is proved that, for each pair (m,n) of non-negative integers, there is a Banach space X for which the group K_0(B(X)) is isomorphic to m copies of the integers and the group K_1(B(X)) is isomorphic to n copies of the integers. Along the way we compute ... More
Analytical approximations for spiral wavesJan 26 2013Sep 20 2013We propose a non-perturbative attempt to solve the kinematic equations for spiral waves in excitable media. From the eikonal equation for the wave front we derive an implicit analytical relation between rotation frequency $\Omega$ and core radius $R_{0}$. ... More
A uniform central limit theorem and efficiency for deconvolution estimatorsAug 03 2012We estimate linear functionals in the classical deconvolution problem by kernel estimators. We obtain a uniform central limit theorem with $\sqrt{n}$-rate on the assumption that the smoothness of the functionals is larger than the ill-posedness of the ... More
Adaptive confidence bands for Markov chains and diffusions: Estimating the invariant measure and the driftDec 22 2014Jul 07 2016As a starting point we prove a functional central limit theorem for estimators of the invariant measure of a geometrically ergodic Harris-recurrent Markov chain in a multi-scale space. This allows to construct confidence bands for the invariant density ... More
Market Mechanism Design for Profitable On-Demand Transport ServicesJan 07 2015On-demand transport services in the form of dial-a-ride and taxis are crucial parts of the transport infrastructure in all major cities. However, not all on-demand transport services are equal. In particular, not-for-profit dial-a-ride services with coordinated ... More
Geometric Modular Action, Wedge Duality and Lorentz Covariance are Equivalent for Generalized Free FieldsOct 20 1999The Tomita-Takesaki modular groups and conjugations for the observable algebras of space-like wedges and the vacuum state are computed for translationally covariant, but possibly not Lorentz covariant, generalized free quantum fields in arbitrary space-time ... More
Homotopy theory of symmetric powersOct 16 2015Oct 29 2015We introduce the symmetricity notions of symmetric h-monoidality, symmetroidality, and symmetric flatness. As shown in our paper arXiv:1410.5675, these properties lie at the heart of the homotopy theory of colored symmetric operads and their algebras. ... More
Conformally embedded spacetimes and the space of null geodesicsJan 02 2019It is shown that the space of null geodesics of a causally simple Lorentzian manifold is Hausdorff if it admits an open conformal embedding into a globally hyperbolic spacetime. This provides an obstruction to conformal embeddings of causally simple spacetimes ... More
Decisive creatures and large continuumJan 04 2006Jul 10 2008For $f,g\in\omega\ho$ let $\mycfa_{f,g}$ be the minimal number of uniform $g$-splitting trees needed to cover the uniform $f$-splitting tree, i.e. for every branch $\nu$ of the $f$-tree, one of the $g$-trees contains $\nu$. $\myc_{f,g}$ is the dual notion: ... More
Admissibility and rectification of colored symmetric operadsOct 21 2014Oct 29 2015We establish a flexible condition that guarantees that all colored symmetric operads in a symmetric monoidal model category are admissible, i.e., the category of algebras over any operad admits a model structure transferred from the original model category. ... More
Option calibration of exponential Lévy models: Confidence intervals and empirical resultsFeb 27 2012Oct 17 2012Observing prices of European put and call options, we calibrate exponential L\'evy models nonparametrically. We discuss the efficient implementation of the spectral estimation procedures for L\'evy models of finite jump activity as well as for self-decomposable ... More
How important is tropospheric humidity for coastal rainfall in the tropics?Mar 08 2016May 05 2016Recent research has community have shown that tropical convection and rainfall is sensitive to mid-tropospheric humidity. Therefore it has been suggested to improve the representation of moist convection by making cumulus parameterizations more sensitive ... More
Algebraic independence of (cyclotomic) harmonic sumsOct 13 2015An expression in terms of (cyclotomic) harmonic sums can be simplified by the quasi-shuffle algebra in terms of the so-called basis sums. By construction, these sums are algebraically independent within the quasi-shuffle algebra. In this article we show ... More
Immersed solutions of Plateau's problem for piecewise smooth boundary curves with small total curvatureMar 07 2011Feb 28 2012We provide a new proof of the classical result that any closed rectifiable Jordan curve Gamma in space being piecewise of class C^2 bounds at least one immersed minimal surface of disc-type, under the additional assumption that the total curvature of ... More
Symmetric operads in abstract symmetric spectraOct 21 2014We show that all colored symmetric operads in symmetric spectra valued in a symmetric monoidal model category are admissible, i.e., algebras over such operads carry a model structure. For example, this applies to commutative ring spectra and E-infinity-ring ... More
Near-Optimal Lower Bounds on Quantifier Depth and Weisfeiler-Leman Refinement StepsAug 31 2016Sep 01 2016We prove near-optimal trade-offs for quantifier depth versus number of variables in first-order logic by exhibiting pairs of $n$-element structures that can be distinguished by a $k$-variable first-order sentence but where every such sentence requires ... More
Arithmetic in the fundamental group of a p-adic curve: On the p-adic section conjecture for curvesNov 05 2011We establish a valuative version of Grothendieck's section conjecture for curves over p-adic local fields. The image of every section is contained in the decomposition subgroup of a valuation which prolongs the p-adic valuation to the function field of ... More
Preserving PreservationMay 05 2004We present preservation theorems for countable support iteration of nep forcing notions satisfying ``old reals are not Lebesgue null'' and ``old reals are not meager''. (Nep is a generalization of Suslin proper.) We also give some results for general ... More
Partial and Conditional Expectations in Markov Decision Processes with Integer WeightsFeb 12 2019The paper addresses two variants of the stochastic shortest path problem ('optimize the accumulated weight until reaching a goal state') in Markov decision processes (MDPs) with integer weights. The first variant optimizes partial expected accumulated ... More
Consistency in Drift-ordered Fluid EquationsJul 31 2018We address several concerns related to the derivation of drift-ordered fluid equations. Starting from a fully Galilean invariant fluid system, we show how consistent sets of perturbative drift-fluid equations in the case of a isothermal collisionless ... More
Bernstein - von Mises theorems for statistical inverse problems II: Compound Poisson processesSep 22 2017We study nonparametric Bayesian statistical inference for the parameters governing a pure jump process of the form $$Y_t = \sum_{k=1}^{N(t)} Z_k,~~~ t \ge 0,$$ where $N(t)$ is a standard Poisson process of intensity $\lambda$, and $Z_k$ are drawn i.i.d. ... More
A Falsification View of Success TypingFeb 04 2015Feb 05 2015Dynamic languages are praised for their flexibility and expressiveness, but static analysis often yields many false positives and verification is cumbersome for lack of structure. Hence, unit testing is the prevalent incomplete method for validating programs ... More
Creature forcing and large continuum: The joy of halvingMar 17 2010For $f,g\in\omega^\omega$ let $c^\forall_{f,g}$ be the minimal number of uniform $g$-splitting trees needed to cover the uniform $f$-splitting tree, i.e., for every branch $\nu$ of the $f$-tree, one of the $g$-trees contains $\nu$. Let $c^\exists_{f,g}$ ... More
There are No Causality Problems for Fermi's Two Atom SystemMar 04 1994A repeatedly discussed gedanken experiment, proposed by Fermi to check Einstein causality, is reconsidered. It is shown that, contrary to a recent statement made by Hegerfeldt, there appears no causality paradoxon in a proper theoretical description of ... More