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Photons in a BallOct 15 2015Dec 16 2015The electromagnetic field inside a spherical cavity of large radius R is considered in the presence of stationary charge and current densities. R provides infra-red regularization while maintaining gauge invariance. The quantum ground state of physical ... More

On the number of soft quanta in classical field configurationsJun 26 2013Aug 26 2013A crucial ingredient in the large-N quantum portrait of black holes proposed by Dvali and Gomez is the estimate of the number of soft quanta that make up the classical gravitational field. It is argued here that the coherent state formalism provides a ... More

Ladder operators for Klein-Gordon equation with scalar curvature termOct 03 2017Dec 20 2017Recently, Cardoso, Houri and Kimura constructed generalized ladder operators for massive Klein-Gordon scalar fields in space-times with conformal symmetry. Their construction requires a closed conformal Killing vector, which is also an eigenvector of ... More

Hawking radiation is corpuscularJun 06 2016Jun 29 2016The total number of Hawking quanta emitted during the evaporation of a Schwarzschild black hole is proportional to the square of the initial mass or, equivalently, to the Bekenstein entropy. This simple, but little appreciated, fact is interpreted in ... More

Generalized Supergravity Equations and Generalized Fradkin-Tseytlin CountertermApr 12 2019The generalized Fradkin-Tseytlin counterterm for the (type I) Green-Schwarz superstring is determined for background fields satisfying the generalized supergravity equations (GSE). For this purpose, we revisit the derivation of the GSE based upon the ... More

Generalized Supergravity Equations and Generalized Fradkin-Tseytlin CountertermApr 12 2019May 02 2019The generalized Fradkin-Tseytlin counterterm for the (type I) Green-Schwarz superstring is determined for background fields satisfying the generalized supergravity equations (GSE). For this purpose, we revisit the derivation of the GSE based upon the ... More

Quantum Portrait of a Black Hole with Pöschl-Teller PotentialMar 06 2014Mar 13 2014We improve upon the simple model studied by Casadio and Orlandi [JHEP 1308 (2013) 025] for a black hole as a condensate of gravitons. Instead of the harmonic oscillator potential, the P\"oschl-Teller potential is used, which allows for a continuum of ... More

New Results on Holographic Three-Point FunctionsOct 14 2003Dec 18 2003We exploit a gauge invariant approach for the analysis of the equations governing the dynamics of active scalar fluctuations coupled to the fluctuations of the metric along holographic RG flows. In the present approach, a second order ODE for the active ... More

Spectra of Certain Holographic ABJM Wilson Loops in Higher Rank RepresentationsSep 22 2016The holographic configurations dual to Wilson loops in higher rank representations in the ABJM theory are described by branes with electric flux along their world volumes. In particular, D2 and D6 branes with electric flux play a central role as potential ... More

Effective Fluid Description of the Dark UniverseJul 31 2017Dec 05 2017We propose an effective anisotropic fluid description for a generic infrared-modified theory of gravity. In our framework, the additional component of the acceleration, commonly attributed to dark matter, is explained as a radial pressure generated by ... More

Note on generating functions and connected correlators of 1/2-BPS Wilson loops in $\mathcal{N}=4$ SYM theoryJun 10 2019The generating functions for the Wilson loops in the symmetric and antisymmetric representations of the gauge group $U(N)$ are expressed in terms of the connected correlators of multiply-wound Wilson loops, using ingredients from the representation theory ... More

Antisymmetric Wilson loops in N = 4 SYM: from exact results to non-planar correctionsJul 11 2018Jul 18 2018We consider the vacuum expectation values of 1/2-BPS circular Wilson loops in N=4 super Yang-Mills theory in the totally antisymmetric representation of the gauge group U(N) or SU(N). Localization and matrix model techniques provide exact, but rather ... More

Precise predictions for MSSM Higgs-boson production in bottom-quark fusionOct 12 2007The main production mechanism for supersymmetric Higgs particles at hadron colliders crucially depends on the size of their Yukawa couplings to bottom quarks. For sufficiently large tan(beta) the total cross section for some of the neutral Higgs bosons ... More

Electroweak corrections to dilepton + jet production at hadron collidersMar 04 2011Jul 13 2011The first calculation of the next-to-leading-order electroweak corrections to Z-boson + jet hadroproduction including leptonic Z-boson decays is presented, i.e. to the production of a charged lepton--anti-lepton final state in association with one hard ... More

Electroweak precision for W+jet productionJan 14 2010In this talk we discuss the next-to-leading-order electroweak (EW) corrections to W-boson + jet hadroproduction [1] and compare the full result to a simple approximation assuming factorization of EW and QCD corrections for the charged-current Drell-Yan ... More

Non-connective K- and Nil-spectra of additive categorieMar 06 2013Sep 04 2013We present an elementary construction of the non-connective algebraic K-theory spectrum associated to an additive category following the contracted functor approach due to Bass. It comes with a universal property that easily allows us to identify it with ... More

Splitting the relative assembly map, Nil-terms and involutionsJan 12 2015Oct 06 2015We show that the relative Farrell-Jones assembly map from the family of finite subgroups to the family of virtually cyclic subgroups for algebraic K-theory is split injective in the setting where the coefficients are additive categories with group action. ... More

Simplicial Differential Calculus, Divided Differences, and Construction of Weil FunctorsSep 13 2010Jan 11 2011We define a simplicial differential calculus by generalizing divided differences from the case of curves to the case of general maps, defined on general topological vector spaces, or even on modules over a topological ring K. This calculus has the advantage ... More

Probing the MSSM flavor structure with low energy CP violationSep 15 2009We report on an extensive analysis of FCNC and CPV effects in SUSY theories. We present results for Delta F=2 and Delta F=1 processes governed by b --> s transitions both in the low and high tanbeta regime, focussing in particular on S_psi_phi, the phase ... More

On Calibrating Stochastic Volatility Models with time-dependent ParametersOct 06 2010We consider stochastic volatility models using piecewise constant parameters. We suggest a hybrid optimization algorithm for fitting the models to a volatility surface and provide some numerical results. Finally, we provide an outlook on how to further ... More

Comment on the paper: Quantum backaction of optical observations on Bose-Einstein condensates by U. Leonhardt, T. Kiss, and P. Piwnicki, Eur. Phys. J. D7, 413 (1999)Jun 27 2000A recent paper, Quantum backaction of optical observations on Bose-Einstein condensates by U. Leonhardt, T. Kiss, and P. Piwnicki, Eur. Phys. J. D7, 413 (1999), emphasized that the limit of dispersive imaging of Bose-Einstein condensates with off-resonant ... More

Strain mediated adatom stripe morphologies on Cu<111> simulatedJul 27 2012Jan 29 2013Substrate strain mediated adatom configurations on Cu<111> surfaces have been simulated in a coverage range up to nearly 1 monolayer. Interacting adatoms occupy positions on a triangular lattice in two dimensions. The elastic interaction is taken from ... More

Strain Induced Adatom CorrelationsMar 10 2012A Born-Green-Yvon type model for adatom density correlations is combined with a model for adatom interactions mediated by the strain in elastic anisotropic substrates. The resulting nonlinear integral equation is solved numerically for coverages from ... More

The most powerful particles in the Universe: a cosmic smashMay 06 2013This year we are celebrating 101 years since the discovery of cosmic rays. They are whizzing all around the Universe, and they occur at very different energies, including the highest particle energies that exist. However, theory predicts an abrupt suppression ... More

Flavor Changing Neutral Current Processes in a SO(10) SUSY GUT with Family SymmetryOct 08 2007We report on a detailed analysis of a SO(10) SUSY GUT model of Dermisek and Raby (DR) with a D3 family symmetry. The model is completely specified in terms of only 24 parameters and is able to successfully describe both quark and lepton masses and mixings, ... More

Supersymmetry and other beyond the Standard Model physics: Prospects for determining mass, spin and CP propertiesDec 10 2008The prospects of measuring masses, spin and CP properties within Supersymmetry and other beyond the Standard Model extensions at the LHC are reviewed. Emphasis is put on models with missing transverse energy due to undetected particles, as in Supersymmetry ... More

Westerlund 1 and its Galactic siblings -Observation confronts TheoryMar 13 2008Because of their large number of stars spread over the entire stellar mass spectrum, starburst clusters are highly suitable to benchmark and calibrate star formation models and theories. Among the handful of Galactic starburst clusters, Westerlund 1 with ... More

Full Salpeter Equation with Confining Interactions: Analytic Stability ProofOct 30 2008The most popular 3-dimensional reduction of the Bethe-Salpeter formalism for the description of bound states within quantum field theory is the Salpeter equation, found as the instantaneous limit of the Bethe-Salpeter framework if allowing, in addition, ... More

Light scalar meson spectrumNov 23 2001We discuss the classification of the light scalar mesons with mass below 2 GeV into q qbar nonets and glueballs. The information on production and decay of these states, in particular recent information on f_0(980), f_0(400-1200) (or sigma(600)) and f_0(1500) ... More

Scalar mesons: in search of the lightest glueballSep 20 2006According to the QCD expectations the lightest glueball should be a scalar particle (J^{PC}=0^{++}). Different scenarios have been considered for a classification of these states but -- despite considerable progress in recent years -- the experimental ... More

Dynamical modeling and the interactions with the ISMSep 22 2011This paper is a review of some of the recent modeling efforts to improve our understanding of structure formation and evolution of planetary nebulae including their interaction with the interstellar medium. New propositions have been made for the formation ... More

The Calculus of Expected Loss: Backtesting Parameter-Based Expected Loss in a Basel II FrameworkNov 21 2012Aug 08 2013The dependency structure of credit risk parameters is a key driver for capital consumption and receives regulatory and scientific attention. The impact of parameter imperfections on the quality of expected loss (EL) in the sense of a fair, unbiased estimate ... More

On the Solvability of Maxwell's EquationsSep 13 2012Complementing a study which was published in this journal in 2005, we present explicit calculations of fields predicted by Maxwell's equations both in Lorenz and in Coulomb gauge. Analytic expressions are obtainable, when the source of the fields is an ... More

On Scalar and Vector Potentials for the Nonlinear Electromagnetic ForcesMay 08 2008The potential concept that is successful in classical electrodynamics should also be applicable to the nonlinear electromagnetic forces acting on matter. The obvious method of determining these potentials should be provided by Helmholtz's theorem. It ... More

Electroweak Precision Tests with a Future Linear ColliderOct 26 2001Future high energy linear electron positron colliders with centre-of-mass enegies between 90 and 1000 GeV offer a unique opportunity to study precisely the Standard Model and phenomena from new physics. Most important, the mechanism of electroweak symmetry ... More

Application of Microlocal Analysis to the Theory of Quantum Fields Interacting with a Gravitational FieldJan 10 1997It is explained how techniques from microlocal analysis can be used to settle some long-standing questions that arise in the study of the interaction of quantum matter fields with a classical gravitational background field.

Adiabatic Vacua and Hadamard States for Scalar Quantum Fields on Curved SpacetimeJul 19 1995Quasifree states of a linear Klein-Gordon quantum field on globally hyperbolic spacetime manifolds are considered. Using techniques from the theory of pseudodifferential operators and wavefront sets on manifolds a criterion for a state to be an Hadamard ... More

Robust Processing of Natural LanguageJul 13 1995Jul 14 1995Previous approaches to robustness in natural language processing usually treat deviant input by relaxing grammatical constraints whenever a successful analysis cannot be provided by ``normal'' means. This schema implies, that error detection always comes ... More

Parsing of Spoken Language under Time ConstraintsSep 09 1994Spoken language applications in natural dialogue settings place serious requirements on the choice of processing architecture. Especially under adverse phonetic and acoustic conditions parsing procedures have to be developed which do not only analyse ... More

Rules of Thumb for Information Acquisition from Large and Redundant DataDec 16 2010We develop an abstract model of information acquisition from redundant data. We assume a random sampling process from data which provide information with bias and are interested in the fraction of information we expect to learn as function of (i) the ... More

Comment on: I-Shih Liu: Constitutive theory of anisotropic rigid heat conductorsJun 15 2011In I-Shih Liu's paper \C{1}, the compatibility of anisotropy and material frame indifference of a rigid heat conductor is investigated. For this purpose, the deformation gradient is introduced into the domain of the constitutive mapping. Because of the ... More

Temperatures of Fragment Kinetic Energy SpectraNov 28 1994Nov 29 1994Multifragmentation reactions without large compression in the initial state (proton-induced reactions, reverse-kinematics, projectile fragmentation) are examined, and it is verified quantitatively that the high temperatures obtained from fragment kinetic ... More

Particle-particle correlations and the space-time structure of heavy ion collisionsFeb 26 1993The present status of the use of two-particle intensity interferometry as a diagnostic tool to study the space-time dynamics of intermediate energy heavy ion collisions is examined. Calculations for the two-proton and two-pion correlation functions are ... More

L^2-Invariants from the Algebraic Point of ViewOct 31 2003We give a survey on L^2-invariants such as L^2-Betti numbers and L^2-torsion taking an algebraic point of view. We discuss their basic definitions, properties and applications to problems arising in topology, geometry, group theory and K-theory.

The Segal Conjecture for Infinite GroupsJan 26 2019We formulate and prove a version of the Segal Conjecture for infinite groups. For finite groups it reduces to the original version. The condition that G is finite is replaced in our setting by the assumption that there exists a finite model for the classifying ... More

The Burnside Ring and Equivariant Stable Cohomotopy for Infinite GroupsApr 04 2005Jul 12 2005After we have given a survey on the Burnside ring of a finite group, we discuss and analyze various extensions of this notion to infinite (discrete) groups. The first three are the finite-G-set-version, the inverse-limit-version and the covariant Burnside ... More

Generating functional for gravitational null initial dataMay 15 2019A field theory on a three-dimensional manifold is introduced, whose field equations are the constraint equations for general relativity on a three-dimensional null hypersurface. The underlying boundary action consists of two copies of the dressed Chern-Simons ... More

Andersen Filtration and Hard LefschetzApr 27 2006Jul 23 2007On the space of homomorphisms from a Verma module to an indecomposable tilting module of the BGG-category O we define a natural filtration following Andersen and establish a formula expressing the dimensions of the filtration steps in terms of coefficients ... More

On $g$-functions for subshiftsAug 10 2006A necessary and sufficient condition is given for a subshift presentation to have a continuous $g$-function. An invariant necessary and sufficient condition is formulated for a subshift to posses a presentation that has a continuous $g$-function.

Survey on geometric group theoryJun 23 2008Sep 11 2008This article is a survey article on geometric group theory from the point of view of a non-expert who likes geometric group theory and uses it in his own research. The sections are: classical examples, basics about quasiisometry,properties and invariants ... More

K- and L-theory of the semi-direct product of the discrete 3-dimensional Heisenberg group by Z/4Dec 08 2004Sep 11 2005We compute the group homology, the topological K-theory of the reduced C^*-algebra, the algebraic K-theory and the algebraic L-theory of the group ring of the semi-direct product of the three-dimensional discrete Heisenberg group by Z/4. These computations ... More

Presentations of symbolic dynamical systems by labelled directed graphs (Notes for a "mini-cours", SDA2, Paris 4-5 October 2007)Sep 10 2012We develop some aspects of a general theory of presentations of subshifts by labelled directed graphs, in particular by compact graphs. Also considered are synchronization properties of subshifts that lead to presentations by countable graphs.

Tables of prehomogeneous modules and étale modules of reductive algebraic groupsOct 22 2016This document contains tables with the classification of prehomogeneous modules for reductive algebraic groups with up to two simple factors due to Sato, Kimura and many others, as well as corresponding tables of the \'etale modules appearing in this ... More

Difference Problems and Differential ProblemsDec 03 2007We state some elementary problems concerning the relation between difference calculus and differential calculus, and we try to convince the reader that, in spite of the simplicity of the statements, a solution of these problems would be a significant ... More

On a Fair Copy of Riemann's 1859 Publication Created by Alfred ClebschDec 09 2015Dec 16 2015We will verify that the fair copy "Ueber die Anzahl der Primzahlen unter einer gegebenen Gr\"osse" found in Riemann's Nachlass is not in Riemann's hand. Further, we will show that this paper was written by Alfred Clebsch and that it was used after Clebsch's ... More

Shadows of graphical mean curvature flowApr 18 2016We consider mean curvature flow of an initial surface that is the graph of a function over some domain of definition in $R^n$. If the graph is not complete then we impose a constant Dirichlet boundary condition at the boundary of the surface. We establish ... More

Fluxon-induced losses in niobium thin-film cavities revisitedApr 15 2019Long standing data from niobium thin film accelerating cavities will be revisited and analyzed by the two-fluid model of RF superconductivity. Firstly, the applicability and limitation of this model are explored using data of the BCS surface resistance ... More

The Poincaré series of some special quasihomogeneous surface singularitiesApr 13 2000Sep 26 2001In the author's paper ''Poincar\'{e} series and monodromy of a two-dimensional quasihomogeneous hypersurface singularity'' a relation is proved between the Poincar\'{e} series of the coordinate algebra of a two-dimensional quasihomogeneous isolated hypersurface ... More

Accelerated Landweber methods based on co-dilated orthogonal polynomialsJun 09 2012Dec 20 2012In this article, we introduce and study accelerated Landweber methods for linear ill-posed problems obtained by an alteration of the coefficients in the three-term recurrence relation of the \nu-methods. The residual polynomials of the semi-iterative ... More

Asymptotic optimality of scalar Gersho quantizersMar 16 2012Jun 21 2013In his famous paper [7] Gersho stressed that the codecells of optimal quantizers asymptotically make an equal contribution to the distortion of the quantizer. Motivated by this fact, we investigate in this paper quantizers in the scalar case, where each ... More

Holonomy Groups of Complete Flat Pseudo-Riemannian Homogeneous SpacesMay 15 2012Aug 13 2012We show that a complete flat pseudo-Riemannian homogeneous manifold with non-abelian linear holonomy is of dimension at least 14. Due to an example constructed in a previous article by Oliver Baues and the author, this is a sharp bound. Also, we give ... More

On the geometry of cohomogeneity one manifolds with positive curvatureJul 23 2007This is a survey on cohomogeneity one manifolds with positive curvature. We discuss the known examples of this type and their geometry and the functions that describe the metric. We also describe the classification of cohomogeneity one manifolds that ... More

Assembly MapsMay 01 2018Jan 02 2019We introduce and analyze the concept of an assembly map from the original homotopy theoretic point of view. We give also interpretations in terms of surgery theory, controlled topology and index theory. The motivation is that prominent conjectures of ... More

Twisting $L^2$-invariants with finite-dimensional representationsSep 30 2015Mar 27 2017We investigate how one can twist L^2-invariants such as L^2-Betti numbers and L^2-torsion with finite-dimensional representations. As a special case we assign to the universal covering of a finite connected CW-complex X together with an element phi in ... More

Bivariate Lagrange interpolation at the node points of Lissajous curves - the degenerate caseMar 03 2015Apr 03 2016In this article, we study bivariate polynomial interpolation on the node points of degenerate Lissajous figures. These node points form Chebyshev lattices of rank $1$ and are generalizations of the well-known Padua points. We show that these node points ... More

Searching for New Physics with Flavor Violating ObservablesJun 04 2012In this talk, I review the status and prospects of several low energy flavor observables that are highly sensitive to New Physics effects. In particular I discuss the implications for possible New Physics in b --> s transitions coming from the recent ... More

Top Quark Cross-Section Measurements at the TevatronDec 02 2003Run II of the Tevatron collider at Fermilab is well under way and data samples larger than those of Run I are at hand. In this contribution I summarize the current status of cross-section measurements for top-quark pair production at the CDF and D0 experiments. ... More

A new numerical method to construct binary neutron star initial dataAug 05 2009We present a new numerical method for the generation of binary neutron star initial data using a method along the lines of the the Wilson-Mathews or the closely related conformal thin sandwich approach. Our method uses six different computational domains, ... More

Constructing quasi-equilibrium initial data for binary neutron stars with arbitrary spinsSep 24 2012Nov 04 2014In general neutron stars in binaries are spinning. Recently, a new quasi-equilibrium approximation that includes a rotational velocity piece for each star has been proposed to describe binary neutron stars with arbitrary rotation states in quasi-circular ... More

Comment on the paper "Electromagnetic Wave Dynamics in Matter-Wave Superradiant Scattering" by L. Deng, M.G. Payne, and E.W. HagleyOct 19 2010The paper by Deng et al. (Phys. Rev. Lett. 104, 050402 (2010)) presents an analytic theoretical description of matter-wave superradiance (Phys. Rev. Lett. 85, 4225-4228 (2000)) which claims to go beyond previous theoretical frameworks. I show here that ... More

Chiral gauge theories on the lattice without gauge fixing?Nov 30 1993We discuss two proposals for a non-perturbative formulation of chiral gauge theories on the lattice. In both cases gauge symmetry is broken by the regularization. We aim at a dynamical restoration of symmetry. If the gauge symmetry breaking is not too ... More

Limiting soft particle production and QCDNov 10 2010We present some basic elements of the treatment of particle multiplicities in jets from high energy collisions within perturbative QCD. Then we discuss the universal features of the inclusive particle spectrum for the limiting case of momentum p\to 0 ... More

Scaling and scale breaking phenomena in QCD jetsNov 12 1996The perturbative QCD approach to multiparticle production assuming Local Parton Hadron Duality (LPHD) and some recent results are discussed. Finite asymptotic scaling limits are obtained for various observables, after an appropriate rescaling, in the ... More

UNIVERSAL PROPERTIES OF ANGULAR CORRELATIONS IN QCD JETSJan 16 1995Predictions for angular correlations between an arbitrary number of partons are derived in the high energy limit. The quantities considered depend on angles and primary energy through a single variable $\epsilon$ which implies certain scaling properties ... More

Predicting and generating time series by neural networks: An investigation using statistical physicsOct 23 2000An overview is given about the statistical physics of neural networks generating and analysing time series. Storage capacity, bit and sequence generation, prediction error, antipredictable sequences, interacting perceptrons and the application on the ... More

Theory of Interacting Neural NetworksApr 02 2002In this contribution we give an overview over recent work on the theory of interacting neural networks. The model is defined in Section 2. The typical teacher/student scenario is considered in Section 3. A static teacher network is presenting training ... More

Measurement of the CKM Matrix Elements |Vcb| and |Vub| at the B-factoriesJul 18 2006Recent results on inclusive and exclusive semileptonic B decays from B-factories are presented. The impact of these measurements on the determination of the CKM matrix elements |Vub| and |Vcb| is discussed.

2d quantum gravity with torsion, dilaton theory and black hole formationOct 06 2000Starting from the work of the author in 1990 with different collaborators, essential progress in 2d gravity theories has been made. Now all such theories (and not only certain special models) can be treated at the classical as well as at the quantum level. ... More

Estimates for spectral density functions of matrices over C[Z^d]Oct 31 2013Oct 29 2014We give a polynomial bound on the spectral density function of a matrix over the complex group ring of Z^d. It yields an explicit lower bound on the Novikov-Shubin invariant associated to this matrix showing in particular that the Novikov-Shubin invariant ... More

Lie CalculusFeb 27 2017Jun 28 2017We explain that general differential calculus and Lie theory have a common foundation: Lie Calculus is differential calculus, seen from the point of view of Lie theory, by making use of the groupoid concept as link between them. Higher order theory naturally ... More

Hadron Physics from Lattice QCDMay 25 2016We sketch the basic ideas of the lattice regularization in Quantum Field Theory, the corresponding Monte Carlo simulations, and applications to Quantum Chromodynamics (QCD). This approach enables the numerical measurement of observables at the non-perturbative ... More

Simplified Bethe-Salpeter Description of Basic Pseudoscalar-Meson FeaturesJul 11 2018We assess a description of pseudoscalar mesons as pseudo-Goldstone bosons by its compatibility with some Gell-Mann-Oakes-Renner-type relation.

An Essay on the Completion of Quantum Theory. I: General SettingNov 23 2017We propose a geometric setting of the axiomatic mathematical formalism of quantum theory. Guided by the idea that understanding the mathematical structures of these axioms is of similar importance as was historically the process of understanding the axioms ... More

Second Law and Non-Equilibrium Entropy of Schottky Systems -- Doubts and VerificationJul 11 2018Meixner's historical remark in 1969 "... it can be shown that the concept of entropy in the absence of equilibrium is in fact not only questionable but that it cannot even be defined...." is investigated from today's insight. Several statements --such ... More

On a class of highly symmetric Markov-Dyck shiftsJun 06 2018Jun 07 2018A class of highly symmetric Markov-Dyck shifts is introduced. Expressions for zeta functions are derived and topological entropies are determined.

A spectral interpolation scheme on the unit sphere based on the nodes of spherical Lissajous curvesFeb 19 2018Jul 20 2018For sampling values along spherical Lissajous curves we establish a spectral interpolation and quadrature scheme on the sphere. We provide a mathematical analysis of spherical Lissajous curves and study the characteristic properties of their intersection ... More

Survey on Classifying Spaces for Families of SubgroupsDec 19 2003Jun 02 2004We define for a topological group G and a family of subgroups F two versions for the classifying space for the family F, the G-CW-version E_F(G) and the numerable G-space version J_F(G). They agree if G is discrete, or if G is a Lie group and each element ... More

Integral geometry of translation invariant functionals, II: The case of general convex bodiesAug 05 2015Aug 18 2016In continuation of Part I, we study translative integral formulas for certain translation invariant functionals, which are defined on general convex bodies. Again, we consider local extensions and use these to show that the translative formulas extend ... More

An Additivity theorem for cobordism categoriesMay 10 2018Oct 25 2018Using methods inspired from algebraic $K$-theory, we give a new proof of the Genauer fibration sequence, relating the cobordism categories of closed manifolds with cobordism categories of manifolds with boundaries, and of the B\"okstedt-Madsen delooping ... More

On the universal property of Waldhausen's K-theoryMar 06 2017In this note we show that Waldhausen's K-theory functor from Waldhausen categories to spaces has a universal property: It is the target of the "universal global Euler characteristic", in other words, the "additivization" of the functor sending a Waldhausen ... More

Non-trivial self-concordances and a recent conjecture by BotvinnikDec 12 2012The goal of this note is to construct, on many manifolds, non-trivial concordances from the identity to itself. This produces counterexamples to a recent conjecture by Botvinnik.

Lehmer's Problem for arbitrary groupsJan 03 2019We consider the problem whether for a group G there exists a constant Lambda(G) > 1 such that for any (r,s)-matrix A over the integral group ring ZG the Fuglede-Kadison determinant of the G-equivariant bounded operator from L^2(G)^r to L^2(G)^s given ... More

Riemannian Manifolds with positive sectional curvatureOct 15 2012This is a survey of recent results on manifolds with positive curvature from a series of lecture given in Guanajuato, Mexico in 2010. It also contains some hitsorical comments.

Theorem and Algorithm Checking for Courses on Logic and Formal MethodsApr 01 2019The RISC Algorithm Language (RISCAL) is a language for the formal modeling of theories and algorithms. A RISCAL specification describes an infinite class of models each of which has finite size; this allows to fully automatically check in such a model ... More

On compact homogeneous $\mathrm{G}_{2(2)}$-manifoldsAug 30 2018We prove that among all compact homogeneous spaces for an effective transitive action of a Lie group whose Levi subgroup has no compact simple factors, the seven-dimensional flat torus is the only one that admits an invariant torsion-free $\mathrm{G}_{2(2)}$-structure. ... More

A Supplement to the Classification of Flat Homogeneous Spaces of Signature (m,2)Dec 08 2013Jun 23 2015Duncan and Ihrig (1993) gave a classification of the flat homogeneous spaces of metric signature (m,2), provided that a certain condition on the development image of these spaces holds. In this note we show that this condition can be dropped, so that ... More

Jordan structures and non-associative geometryJun 11 2007In this survey paper we give an overview over constructions of geometries associated to Jordan structures (algebras, triple systems and pairs), featuring analogs of these constructions with the Lie functor on the one hand and with the approach of non-commutative ... More

A note on distinguished bases of singularitiesNov 18 2016Jun 12 2017For an isolated hypersurface singularity which is neither simple nor simple elliptic, it is shown that there exists a distinguished basis of vanishing cycles which contains two basis elements with an arbitrary intersection number. This implies that the ... More

Phenomenology of CP Violation in a Flavor Blind MSSM and BeyondNov 02 2009We present an analysis of low energy CP violating observables in the Minimal Supersymmetric Standard Model (MSSM). We focus on the predictions of CP violation in b -> s transitions in the framework of a flavor blind MSSM, where the CKM matrix remains ... More

Galactic polarization surveysMar 17 2006Following the detection of polarized diffuse Galactic emission in 1962 a number of surveys were undertaken at low frequencies in the following years resulting in important insights on the local magnetic field, polarization of the giant radio loops and ... More