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Results for "Florian J. Kolb"

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Formation of Acetaldehyde on CO-rich IcesApr 12 2019The radicals HCO and CH$_3$ on carbon monoxide ice surfaces were simulated using density functional theory. Their binding energy on amorphous CO ice shows broad distributions, with approximative average values of 500 K for HCO and 200 K for CH$_3$. If ... More
Synthetic Spectral Analysis of the Hot Component in the S-Type Symbiotic Variable EG AndromedaJul 26 2004We have applied grids of NLTE high gravity model atmospheres and optically thick accretion disk models for the first time to archival IUE and FUSE spectra of the S-type symbiotic variable EG And taken at superior spectroscopic conjunction when Rayleigh ... More
Gravitational production of super-Hubble-mass particles: an analytic approachDec 01 2018Dec 08 2018Through a mechanism similar to perturbative particle scattering, particles of mass $m_\chi$ larger than the Hubble expansion rate $H_\mathrm{inf}$ during inflation can be gravitationally produced at the end of inflation without the exponential suppression ... More
Extra dimensions present a new flatness problemAug 14 2000There is no known fundamental reason to demand as a cosmological initial condition that the bulk possess an SO(3,1) isometry. On the contrary, one expects bulk curvature terms that violate the SO(3,1) isometry at early epochs, leading to a violation of ... More
Production of massive particles during reheatingSep 18 1998What is commonly called the reheat temperature, $T_{RH}$, is not the maximum temperature obtained after inflation. The maximum temperature is, in fact, much larger than $T_{RH}$. As an application of this we consider the production of massive stable dark-matter ... More
On the relic abundance of light photinosMar 22 1997We solve the coupled Boltzmann equation for the system of light photinos interacting with pions and $R^0$'s (the gluon-gluino bound state) to determine the relic abundance of light photinos in the light gaugino scenario. Cosmology bounds the ratio r of ... More
WIMPZILLAS!Oct 14 1998There are many reasons to believe the present mass density of the universe is dominated by a weakly interacting massive particle (WIMP), a fossil relic of the early universe. Theoretical ideas and experimental efforts have focused mostly on production ... More
Superheavy dark matterFeb 05 1998May 26 1998We show that in large-field inflationary scenarios, superheavy (many orders of magnitude larger than the weak scale) dark matter will be produced in cosmologically interesting quantities if superheavy stable particles exist in the mass spectrum. We show ... More
Are ultrahigh energy cosmic rays signals of supersymmetry?Jul 02 1997Dec 19 1997We investigate the possibility that cosmic rays of energy larger than the Greisen-Zatsepin-Kuzmin cutoff are not nucleons, but a new stable, massive, hadron that appears in many extensions of the standard model. We focus primarily on the S^0, a uds-gluino ... More
Nonthermal Supermassive Dark MatterMay 27 1998Sep 25 1998We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may be elementary particles of mass much greater than the weak scale. Searches for dark matter should not be limited to weakly interacting ... More
Quantum Symmetric Pairs and the Reflection EquationDec 27 2005Sep 06 2006It is shown that central elements in G. Letzter's quantum group analogs of symmetric pairs lead to solutions of the reflection equation. This clarifies the relation between Letzter's approach to quantum symmetric pairs and the approach taken by M. Noumi, ... More
A Simplicial Calculus for Local Intersection Numbers at Nonarchimedian Places on Products of Semi-stable CurvesApr 06 2014We analyse the subring of the Chow ring with support generated by the irreducible components of the special fibre of the Gross-Schoen desingularization of a d-fold self product of a semi-stable curve over the spectrum of a discrete valuation ring. For ... More
Quantum symmetric Kac-Moody pairsJul 25 2012Sep 29 2014The present paper develops a general theory of quantum group analogs of symmetric pairs for involutive automorphism of the second kind of symmetrizable Kac-Moody algebras. The resulting quantum symmetric pairs are right coideal subalgebras of quantized ... More
An Analytic Description of Local Intersection Numbers at Non-Archimedian Places for Products of Semi-Stable CurvesApr 10 2014We generalise a formula of Shou-Wu Zhang, which describes local arithmetic intersection numbers of three Cartier divisors with support in the special fibre on a a self-product of a semi-stable arithmetic surface using elementary analysis. By an approximation ... More
Binary evolution with relativistic jetsOct 20 1998Relativistic jets can extract mass-energy from a black hole. In semi-detached black hole binaries the jet ejection process constitutes a `consequential angular momentum loss' (CAML) process. The effect of this jet-induced CAML is to lower the transfer ... More
Braided module categories via quantum symmetric pairsMay 11 2017Let $\mathfrak{g}$ be a finite dimensional complex semisimple Lie algebra. The finite dimensional representations of the quantized enveloping algebra $U_q({\mathfrak g})$ form a braided monoidal category $O_{int}$. We show that the category of finite ... More
Radial part calculations for affine sl2 and the Heun KZB-heat equationOct 02 2013In the present paper we determine the radial part of the Casimir element for the Lie algebra affine sl2 with respect to the Chevalley involution. The resulting operator is identified with a blend of the Inozemtsev Hamiltonian and the KZB-heat equation ... More
The AS-Cohen-Macaulay property for quantum flag manifolds of minuscule weightJul 10 2007It is shown that quantum homogeneous coordinate rings of generalised flag manifolds corresponding to minuscule weights, their Schubert varieties, big cells, and determinantal varieties are AS-Cohen-Macaulay. The main ingredient in the proof is the notion ... More
On the largest prime factor of the $k-$Fibonacci numbersOct 15 2012Let $P(m)$ denote the largest prime factor of an integer $m\geq 2$, and put $P(0)=P(1)=1$. For an integer $k\geq 2$, let $(F_{n}^{(k)})_{n\geq 2-k}$ be the $k-$generalized Fibonacci sequence which starts with $0,...,0,1$ ($k$ terms) and each term afterwards ... More
Multi-Conjugate Adaptive Optics images of the Trapezium ClusterSep 25 2007Multi-Conjugate Adaptive Optics (MCAO) combines the advantages of standard adaptive optics, which provides high contrast and high spatial resolution, and of wide field ~1' imaging. Up to recently, MCAO for astronomy was limited to laboratory experiments. ... More
Artificial variability in XMM-Newton observations of X-ray sources: M31 as a case studyOct 02 2006Power density spectra (PDS) that are characteristic of low mass X-ray binaries (LMXBs) have been previously reported for M31 X-ray sources observed by XMM-Newton. However, we have recently discovered that these PDS are false positives resulting from the ... More
The systemic velocities of four long-period cataclysmic variable starsJan 31 2002Although a large number of orbital periods of cataclysmic variable stars (CVs) have been measured, comparison of period and luminosity distributions with evolutionary theory is affected by strong selection effects. A test has been discovered which is ... More
Probing Planckian physics: resonant production of particles during inflation and features in the primordial power spectrumOct 21 1999The phenomenon of resonant production of particles {\it after} inflation has received much attention in the past few years. In a new application of resonant production of particles, we consider the effect of a resonance {\em during} inflation. We show ... More
On the gravitational production of superheavy dark matterApr 10 2001Apr 11 2001The dark matter in the universe can be in the form of a superheavy matter species (WIMPZILLA). Several mechanisms have been proposed for the production of WIMPZILLA particles during or immediately following the inflationary epoch. Perhaps the most attractive ... More
Isocurvature constraints on gravitationally produced superheavy dark matterNov 16 2004We show that the isocurvature perturbations imply that the gravitationally produced superheavy dark matter must have masses larger than few times the Hubble expansion rate at the end of inflation. This together with the bound on tensor to scalar contribution ... More
Population synthesis of wide binary millisecond pulsarsAug 18 2002Four evolutionary channels leading to the formation of wide binary millisecond pulsars are investigated. The majority of binary millisecond pulsars are found to descend from systems in which the most massive component undergoes a common-envelope phase ... More
The orbital period distribution of wide binary millisecond pulsarsApr 02 2004Apr 06 2004We present results of a binary population synthesis study on the orbital period distribution of wide binary millisecond pulsars forming through four evolutionary channels. In three of the channels, the progenitor of the millisecond pulsar undergoes a ... More
The bar involution for quantum symmetric pairsSep 17 2014Jan 29 2016We construct a bar involution for quantum symmetric pair coideal subalgebras $B_{\mathbf{c},\mathbf{s}}$ corresponding to involutive automorphisms of the second kind of symmetrizable Kac-Moody algebras. To this end we give unified presentations of these ... More
Braid group action and root vectors for the $q$-Onsager algebraJun 27 2017Aug 08 2017We define two algebra automorphisms $T_0$ and $T_1$ of the $q$-Onsager algebra $B_c$, which provide an analog of G. Lusztig's braid group action for quantum groups. These automorphisms are used to define root vectors which give rise to a PBW basis for ... More
Spectral Analysis of Diffusions with Jump BoundaryJan 13 2011In this paper we consider one-dimensional diffusions with constant coefficients in a finite interval with jump boundary and a certain deterministic jump distribution. We use coupling methods in order to identify the spectral gap in the case of a large ... More
Cavity OptomechanicsMar 04 2013We review the field of cavity optomechanics, which explores the interaction between electromagnetic radiation and nano- or micromechanical motion. This review covers the basics of optical cavities and mechanical resonators, their mutual optomechanical ... More
Power of Two as sums of Three Pell NumbersAug 22 2016In this paper, we find all the solutions of the Diophantine equation $P_\ell + P_m +P_n=2^a$, in nonnegative integer variables $(n,m,\ell, a)$ where $P_k$ is the $k$-th term of the Pell sequence $\{P_n\}_{n\ge 0}$ given by $P_0=0$, $P_1=1$ and $P_{n+1}=2P_{n}+ ... More
A Geometric Approach to Dynamical Model-Order ReductionMay 23 2017Any model order reduced dynamical system that evolves a modal decomposition to approximate the discretized solution of a stochastic PDE can be related to a vector field tangent to the manifold of fixed rank matrices. The Dynamically Orthogonal (DO) approximation ... More
A Potential Supernova Remnant/X-ray Binary Association in M31Aug 08 2005The well-studied X-ray/Optical/Radio supernova remnant DDB 1-15 (CXOM31 J004327.8+411829; r3-63) in M31 has been investigated with archival XMM-Newton and Chandra observations. The timing data from XMM-Newton reveals a power density spectrum (PDS) characteristic ... More
On the late spectral types of cataclysmic variable secondariesApr 21 2000We investigate why the spectral type of most cataclysmic variable (CV) secondaries is significantly later than that of a ZAMS star with the same mean density. Using improved stellar input physics, tested against observations of low-mass stars at the bottom ... More
Brown Dwarfs and the Cataclysmic Variable Period MinimumJun 28 1999Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs we calculate the secular evolution of low-mass donor cataclysmic variables (CVs), including those which form with a brown dwarf donor. Our ... More
Factorisation of quasi K-matrices for quantum symmetric pairsApr 09 2018The theory of quantum symmetric pairs provides a universal K-matrix which is an analogue of the universal R-matrix for quantum groups. The main ingredient in the construction of the universal K-matrix is a quasi K-matrix which has so far only been constructed ... More
Nonlinear Eigenmodes of a Polariton Harmonic OscillatorJan 28 2015We investigate theoretically the quantum oscillator-like states recently observed experimentally in polariton condensates (Nat. Phys. 8, 190 (2012)). We consider a complex Gross-Pitaevskii type model which includes the effects of self-interactions, and ... More
Compression, inversion, and approximate PCA of dense kernel matrices at near-linear computational complexityJun 07 2017Nov 10 2017Dense kernel matrices $\Theta \in \mathbb{R}^{N \times N}$ obtained from point evaluations of a covariance function $G$ at locations $\{ x_{i} \}_{1 \leq i \leq N}$ arise in statistics, machine learning, and numerical analysis. For covariance functions ... More
Compression, inversion, and approximate PCA of dense kernel matrices at near-linear computational complexityJun 07 2017Mar 22 2019Dense kernel matrices $\Theta \in \mathbb{R}^{N \times N}$ obtained from point evaluations of a covariance function $G$ at locations $\{ x_{i} \}_{1 \leq i \leq N}$ arise in statistics, machine learning, and numerical analysis. For covariance functions ... More
Search for Supersymmetry in the 4-lepton final state with the ATLAS detectorAug 28 2014Aug 29 2014The four-lepton final state, rare in standard model processes, is an attractive channel for new physics searches at the LHC. In supersymmetry (SUSY), charged leptons may arise from R-Parity conserving (RPC) cascade decays of SUSY particles to the lightest ... More
A Characterization for the Finiteness of Perpetual Integrals of Levy ProcessesMar 09 2019We derive a criterium for the almost sure finiteness of perpetual integrals of \LL processes for a class of real functions including all continuous functions and for general one-dimensional L\'evy processes that drifts to plus infinity. This generalizes ... More
Homogeneous right coideal subalgebras of quantized enveloping algebrasSep 19 2011For a quantized enveloping algebra of a complex semisimple Lie algebra with deformation parameter not a root of unity, we classify all homogeneous right coideal subalgebras. Any such right coideal subalgebra is determined uniquely by a triple consisting ... More
Maximum principle satisfying CWENO schemes for non-local conservation lawsMar 14 2018Oct 29 2018Central WENO schemes are a natural candidate for higher-order schemes for non-local conservation laws, since the underlying reconstructions do not only provide single point values of the solution but a complete (high-order) reconstruction in every time ... More
Universal K-matrix for quantum symmetric pairsJul 22 2015Jan 29 2016Let $\mathfrak{g}$ be a symmetrizable Kac-Moody algebra and let $U_q(\mathfrak{g})$ denote the corresponding quantized enveloping algebra. In the present paper we show that quantum symmetric pair coideal subalgebras $B_{c,s}$ of $U_q(\mathfrak{g})$ have ... More
Quasistationary distributions for one-dimensional diffusions with singular boundary pointsSep 08 2014Mar 30 2018In the present work we characterize the existence of quasistationary distributions for diffusions on $(0,\infty)$ allowing singular behavior at $0$ and $\infty$. If absorption at 0 is certain, we show that there exists a quasistationary distribution as ... More
Numerical Approach for Corvino-Type Gluing of Brill-Lindquist Initial DataSep 04 2018Building on the work of Giulini and Holzegel (2005), a new numerical approach is developed for computing Cauchy data for Einstein's equations by gluing a Schwarzschild end to a Brill-Lindquist metric via a Corvino-type construction. In contrast to, and ... More
Cosmological Bounds to the Magnetic Moment of Heavy Tau NeutrinosMar 12 1996The magnetic moment of tau neutrinos in the MeV mass range may be large enough to modify the cosmological freeze-out calculation and determine the tau-neutrino relic density. In this paper we revisit such a possibility. We calculate the evolution and ... More
Preheating and symmetry restoration in collisions of vacuum bubblesFeb 19 1996In first-order inflation a phase transition is completed by the collisions of expanding true-vacuum bubbles. If bubble collisions produce large numbers of soft scalar particles carrying quantum numbers associated with a spontaneously broken symmetry, ... More
Reflection equation algebras, coideal subalgebras, and their centresDec 23 2008Reflection equation algebras and related U_q(g)-comodule algebras appear in various constructions of quantum homogeneous spaces and can be obtained via transmutation or equivalently via twisting by a cocycle. In this paper we investigate algebraic and ... More
The SuperWASP catalogue of 4963 RR Lyr stars: identification of 983 Blazhko effect candidatesJul 07 2017Jul 19 2017We set out to compile a catalogue of RRab pulsating variables in the SuperWASP archive and identify candidate Blazhko effect objects within this catalogue. We analysed their light curves and power spectra for correlations in their common characteristics ... More
A comparison of the Bravyi-Kitaev and Jordan-Wigner transformations for the quantum simulation of quantum chemistryDec 05 2018The ability to perform classically intractable electronic structure calculations is often cited as one of the principal applications of quantum computing. A great deal of theoretical algorithmic development has been performed in support of this goal. ... More
Recoil Free Scattering From a Free GasJan 31 2008We present a treatment of decoherence in an atom due to scattering from a gas of free particles. We show that there is a recoil free scattering process that leaves both the atom and the gas in an unchanged state, but allows for the acquisition of a phase ... More
Coincidences in generalized Lucas sequencesFeb 17 2014For an integer $k\geq 2$, let $(L_{n}^{(k)})_{n}$ be the $k-$generalized Lucas sequence which starts with $0,\ldots,0,2,1$ ($k$ terms) and each term afterwards is the sum of the $k$ preceding terms. In this paper, we find all the integers that appear ... More
Pattern phase diagram for 2D arrays of coupled limit-cycle oscillatorsJan 07 2015Arrays of coupled limit-cycle oscillators represent a paradigmatic example for studying synchronization and pattern formation. They are also of direct relevance in the context of currently emerging experiments on nano- and optomechanical oscillator arrays. ... More
Rectification by Doped Mott-Insulator JunctionsAug 08 2012Aug 10 2012Junctions of doped Mott insulators offer a route to rectification at frequencies beyond the terahertz range. Mott insulators have strong electronic correlations and therefore short timescales for electron-electron scattering. It is this short time scale ... More
Solving highly-oscillatory NLS with SAM: numerical efficiency and geometric propertiesAug 06 2013In this paper, we present the Stroboscopic Averaging Method (SAM), recently introduced in [7,8,10,12], which aims at numerically solving highly-oscillatory differential equations. More specifically, we first apply SAM to the Schr\"odinger equation on ... More
Powers of two as sums of two $k-$Fibonacci numbersSep 30 2014For an integer $k\geq 2$, let $(F_{n}^{(k)})_{n}$ be the $k-$Fibonacci sequence which starts with $0,\ldots,0,1$ ($k$ terms) and each term afterwards is the sum of the $k$ preceding terms. In this paper, we search for powers of 2 which are sums of two ... More
An optimal Borsuk-Ulam theorem for products of spheres and Stiefel manifoldsFeb 03 2019We give a new, simplified proof of a general Borsuk--Ulam theorem for a product of spheres, originally due to Ramos. That is, we show the non-existence of certain $(\mathbb{Z}/2)^k$-equivariant maps from a product of $k$ spheres to the unit sphere in ... More
Local chain ordering in amorphous polymer melts: Influence of chain stiffnessJan 22 1999Molecular dynamics simulation of a generic polymer model is applied to study melts of polymers with different types of intrinsic stiffness. Important static observables of the single chain such as gyration radius or persistence length are determined. ... More
Dielectric sensing by charging energy modulation in a nano-granular metalApr 14 2014Several sensing concepts using nanostructures prepared by focused electron beam induced deposition have been developed over the last years. Following work on highly miniaturized Hall sensors for magnetic sensing with soft magnetic Co, strain and force ... More
Optimal control of compressor stations in a coupled gas-to-power networkJan 02 2019Mar 22 2019We introduce a tool for simulation and optimization of gas pipeline networks coupled to power grids by gas-to-power plants. The model under consideration consists of the isentropic Euler equations to describe the gas flow coupled to the AC powerflow equations. ... More
The rate of convergence to stationarity for M/G/1 models with admission controls via couplingJan 02 2012We study the workload processes of two restricted M/G/1 queueing systems: in Model 1 any service requirement that would exceed a certain capacity threshold is truncated; in Model 2 new arrivals do not enter the system if they have to wait more than a ... More
A combined first and second order traffic network modelMar 12 2019Second order macroscopic traffic flow models are well-known to be able to reproduce the so-called capacity drop effect, i.e., the phenomenon that the outflow of a congested region is substantially lower than the maximum achievable flow in this particular ... More
Geometric Ergodicity of a Hypoelliptic Diffusion Modelling The Melt-Spinning Process of Nonwoven MaterialsDec 28 2011We analyze the large time behavior of a stochastic model for the lay-down of fibers on a conveyor belt in the production process of nonwovens. It is shown, that under weak conditions this degenerate diffusion process is strong mixing, confirming a conjecture ... More
Surface plasmon polaritons on rough metal surfaces: Understanding the formation of laser induced periodic surface structures in metalsMar 11 2019The formation of self-organized laser induced periodic surface structures (LIPSS) in metals, semiconductors and dielectrics upon pulsed laser irradiation is a well-known phenomenon, receiving increased attention due to its huge technological potential. ... More
Detection and Implications of Laser-Induced Raman Scattering at Astronomical ObservatoriesJun 21 2017Jan 16 2019(Abr.) Laser guide stars employed at astronomical observatories provide artificial wavefront reference sources to help correct (in part) the impact of atmospheric turbulence on astrophysical observations. Following the recent commissioning of the 4 Laser ... More
On the proof of the dipole approximationSep 06 2013The dipole approximation is widely used to study the interaction of atoms and Lasers. Employing it essentially means to replace the Laser's vector potential A(r,t) in the Hamiltonian by A(0,t). Heuristically this is justified under usual experimental ... More
On the reheating stage after inflationJul 18 2003We point out that inflaton decay products acquire plasma masses during the reheating phase following inflation. The plasma masses may render inflaton decay kinematicaly forbidden, causing the temperature to remain frozen for a period at a plateau value. ... More
Lorentz invariance violation in top-down scenarios of ultrahigh energy cosmic ray creationJun 29 2003Jan 28 2004The violation of Lorentz invariance (LI) has been invoked in a number of ways to explain issues dealing with ultrahigh energy cosmic ray (UHECR) production and propagation. These treatments, however, have mostly been limited to examples in the proton-neutron ... More
Relating Spectral Indices to Tensor and Scalar Amplitudes in InflationMar 01 1994Mar 19 1994Within an expansion in slow-roll inflation parameters, we derive the complete second-order expressions relating the ratio of tensor to scalar density perturbations and the spectral index of the scalar spectrum. We find that ``corrections'' to previously ... More
GUT Baryogenesis after PreheatingJun 07 1996Oct 24 1996At the end of inflation the universe is frozen in a near zero-entropy state with energy density in a coherent scalar field and must be ``defrosted'' to produce the observed entropy and baryon number. We propose that the baryon asymmetry is generated by ... More
Understanding selection effects in observed samples of cataclysmic variablesOct 21 2006Large differences between the properties of the known sample of cataclysmic variable stars (CVs) and the predictions of the theory of binary star evolution have long been recognised. However, because all existing CV samples suffer from strong selection ... More
Why Low-Mass Black-Hole Binaries Are TransientMay 06 1997We consider transient behavior in low-mass X-ray binaries. In short-period neutron-star systems (orbital period less than ~ 1d) irradiation of the accretion disk by the central source suppresses this except at very low mass transfer rates. Formation constraints ... More
On a stochastic Trotter formula with application to spontaneous localization modelsMar 21 2011We consider the relation between so called continuous localization models - i.e. non-linear stochastic Schr\"odinger evolutions - and the discrete GRW-model of wave function collapse. The former can be understood as scaling limit of the GRW process. The ... More
Supervised Deep Kriging for Single-Image Super-ResolutionDec 10 2018We propose a novel single-image super-resolution approach based on the geostatistical method of kriging. Kriging is a zero-bias minimum-variance estimator that performs spatial interpolation based on a weighted average of known observations. Rather than ... More
Optimal control of compressor stations in a coupled gas-to-power networkJan 02 2019We introduce a tool for simulation and optimization of gas pipeline networks coupled to power grids by gas-to-power plants. The model under consideration consists of the isentropic Euler equations to describe the gas flow coupled to the AC powerflow equations. ... More
On the Dipole Approximation with Error EstimatesSep 06 2013May 12 2017The dipole approximation is employed to describe interactions between atoms and radiation. It essentially consists of neglecting the spatial variation of the external field over the atom. Heuristically, this is justified by arguing that the wavelength ... More
Self-stabilizing Overlays for high-dimensional Monotonic SearchabilityAug 30 2018We extend the concept of monotonic searchability for self-stabilizing systems from one to multiple dimensions. A system is self-stabilizing if it can recover to a legitimate state from any initial illegal state. These kind of systems are most often used ... More
On a third order CWENO boundary treatment with application to networks of hyperbolic conservation lawsMar 01 2017Dec 13 2017High order numerical methods for networks of hyperbolic conservation laws have recently gained increasing popularity. Here, the crucial part is to treat the boundaries of the single (one-dimensional) computational domains in such a way that the desired ... More
Modeling and simulation of gas networks coupled to power gridsDec 29 2018In this paper, a mathematical framework for the coupling of gas networks to electric grids is presented to describe in particular the transition from gas to power. The dynamics of the gas flow are given by the isentropic Euler equations, while the power ... More
Residuum-Condition Diagram and Reduction of Over-Complete Endmember-SetsSep 26 2018Extracting reference spectra, or endmembers (EMs) from a given multi- or hyperspectral image, as well as estimating the size of the EM set, plays an important role in multispectral image processing. In this paper, we present condition-residuum-diagrams. ... More
A Godunov type scheme for a class of LWR traffic flow models with non-local fluxFeb 21 2018Apr 27 2018We present a Godunov type numerical scheme for a class of scalar conservation laws with non-local flux arising for example in traffic flow models. The proposed scheme delivers more accurate solutions than the widely used Lax-Friedrichs type scheme. In ... More
Persistence of one-dimensional AR(1)-sequencesJan 13 2018Jul 31 2018For a class of one-dimensional autoregressive processes $(X_n)$ we consider the tail behaviour of the stopping time $T_0=\min \lbrace n\geq 1: X_n\leq 0 \rbrace$. We discuss existing general analytical approaches to this and related problems and propose ... More
Entangled systems are unbounded sources of nonlocal correlations and of certified random numbersFeb 22 2018The outcomes of local measurements made on entangled systems can be certified to be random provided that the generated statistics violate a Bell inequality. This way of producing randomness relies only on a minimal set of assumptions because it is independent ... More
A Query Language for Formal Mathematical LibrariesApr 20 2012One of the most promising applications of mathematical knowledge management is search: Even if we restrict attention to the tiny fragment of mathematics that has been formalized, the amount exceeds the comprehension of an individual human. Based on the ... More
The Validity of Company Valuation Using Discounted Cash Flow MethodsMar 25 2010Apr 03 2010This paper closely examines theoretical and practical aspects of the widely used discounted cash flows (DCF) valuation method. It assesses its potentials as well as several weaknesses. A special emphasize is being put on the valuation of companies using ... More
Higgs Physics in Warped Extra DimensionsMay 30 2011In this talk, I present results for the most important Higgs-boson production cross sections at the LHC and the Tevatron as well as the branching fractions of the relevant decay channels in the custodial Randall-Sundrum model. The results are based on ... More
A Probabilistic Look at Growth-Fragmentation EquationsSep 08 2016In this note, we consider general growth-fragmentation equations from a probabilistic point of view. Using Foster-Lyapunov techniques, we study the recurrence of the associated Markov process depending on the growth and fragmentation rates. We prove the ... More
Quantile Regression for Qualifying Match of GEFCom2017 Probabilistic Load ForecastingSep 10 2018We present a simple quantile regression-based forecasting method that was applied in a probabilistic load forecasting framework of the Global Energy Forecasting Competition 2017 (GEFCom2017). The hourly load data is log transformed and split into a long-term ... More
Second-order mixed-moment model with differentiable ansatz function in slab geometrySep 23 2017We study differentiable mixed-moment models (full zeroth and first moment, half higher moments) for a Fokker-Planck equation in one space dimension. Mixed-moment minimum-entropy models are known to overcome the zero net-flux problem of full-moment minimum ... More
Concatenation and Pasting of Right ProcessesJan 08 2018A universal method for the concatenation of a sequence of Markov right processes is established. It is then applied to the continued pasting of two Markov right processes, which can be used for pathwise constructions of locally defined processes like ... More
Recursion categories of coalgebrasMay 31 2001We construct recursion categories from categories of coalgebras. Let $F$ be a nontrivial endofunctor on the category of sets that weakly preserves pullbacks and such that the category $\textbf{Set}_F$ of $F$-coalgebras is complete. The category $\textbf{Set}_F$ ... More
Kershaw closures for linear transport equations in slab geometry II: high-order realizability-preserving discontinuous-Galerkin schemesFeb 05 2016Aug 02 2016This paper provides a generalization of the realizability-preserving discontinuous-Galerkin scheme for quadrature-based minimum-entropy models to full-moment models of arbitrary order. It is applied to the class of Kershaw closures, which are able to ... More
Relative Node Polynomials for Plane CurvesSep 26 2010Aug 23 2012We generalize the recent work of S. Fomin and G. Mikhalkin on polynomial formulas for Severi degrees. The degree of the Severi variety of plane curves of degree d and delta nodes is given by a polynomial in d, provided delta is fixed and d is large enough. ... More
Universal Consistency and Robustness of Localized Support Vector MachinesMar 19 2017The massive amount of available data potentially used to discover patters in machine learning is a challenge for kernel based algorithms with respect to runtime and storage capacities. Local approaches might help to relieve these issues. From a statistical ... More
Balanced ideals and domains of discontinuity of Anosov representationsOct 26 2018We consider the action of Anosov subgroups of a semi-simple Lie group on the associated flag manifolds. A systematic approach to construct cocompact domains of discontinuity for this action was given by Kapovich, Leeb and Porti in arXiv:1306.3837. For ... More
Complete subgraphs in multipartite graphsOct 08 2009Turan's Theorem states that every graph of a certain edge density contains a complete graph $K^k$ and describes the unique extremal graphs. We give a similar Theorem for l-partite graphs. For large l, we find the minimal edge density $d^k_l$, such that ... More
On the cop number of toroidal graphsApr 16 2019We show that the cop number of toroidal graphs is at most 3. This resolves a conjecture by Schroeder from 2001 which is implicit in a question by Andreae from 1986.
The MMT API: A Generic MKM SystemJun 13 2013The MMT language has been developed as a scalable representation and interchange language for formal mathematical knowledge. It permits natural representations of the syntax and semantics of virtually all declarative languages while making MMT-based MKM ... More