Results for "Ingo Neumann"

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The Hypermultiplet in N = 2 SuperspaceJul 29 1996Global N=2 supersymmetry in four dimensions with a Fayet-Sohnius hypermultiplet and a complex central charge is studied in N = 2 superspace. It is shown how to construct the complete expansion of the hypermultiplet with respect to the central charge. ... More
Extended supersymmetry with gauged central chargeDec 20 1995Feb 07 1996Global N=2 supersymmetry in four dimensions with a gauged central charge is formulated in superspace. To find an irreducible representation of supersymmetry for the gauge connections a set of constraints is given. Then the Bianchi identities are solved ... More
N = 2 Supersymmetric Quantum Black Holes in Five Dimensional Heterotic String VacuaFeb 20 1998Exact black hole solutions of the five dimensional heterotic $S$-$T$-$U$ model including all perturbative quantum corrections and preserving $1/2$ of $N=2$ supersymmetry are studied. It is shown that the quantum corrections yield a bound on electric charges ... More
Non-local conserved charges from defects in perturbed conformal field theoryApr 12 2010Jul 21 2010Perturbing a Virasoro minimal model by the (1,3) primary bulk field results in an integrable field theory. In this paper, an infinite set of commuting conserved charges is obtained by considering defects: a one-parameter family of perturbed defect operators ... More
An elementary and constructive proof of Grothendieck's generic freeness lemmaJul 03 2018We present a new and direct proof of Grothendieck's generic freeness lemma in its general form. Unlike the previously published proofs, it does not proceed in a series of reduction steps and is fully constructive, not using the axiom of choice or even ... More
The Structure, the Dynamics and the Survivability of Social SystemsOct 10 2006Social systems must fulfil four basic functions to ensure their survival in competitive conditions. Social systems must provide for: (1) energy and other necessities of life, (2) security against external and internal threats, (3) identity and self-development, ... More
Casualty Dynamics in Wars and Terrorism and the Scale-Free Organization of Social SystemsJun 20 2006In this paper I propose a 'mechanism' for the explanation of power-law characteristics of casualty dynamics in inter-state wars, intra-state wars and terrorist attacks: the scale-free physical organization of social systems. Other explanations - self-organized ... More
Self-Organized Characteristics of the International SystemJul 03 2007Sep 24 2014Various self-organized characteristics of the international system can be identified with the help of a complexity science perspective. The perspective discussed in this article is based on various complexity science concepts and theories, and concepts ... More
The International System: "At the Edge of Chaos"Nov 30 2006Sep 24 2014The assumption that complex systems function optimally at the edge of chaos seems applicable to the international system as well. In this paper I argue that the normal chaotic war dynamic of the European international system (1495-1945) was temporarily ... More
NLO QCD Corrections to the Polarized Photo- and Hadroproduction of Heavy QuarksMay 12 2000The complete details of our calculation of the NLO QCD corrections to heavy flavor photo- and hadroproduction with longitudinally polarized initial states are presented. The main motivation for investigating these processes is the determination of the ... More
Perturbed Defects and T-Systems in Conformal Field TheoryNov 01 2007Feb 18 2008Defect lines in conformal field theory can be perturbed by chiral defect fields. If the unperturbed defects satisfy su(2)-type fusion rules, the operators associated to the perturbed defects are shown to obey functional relations known from the study ... More
Quantum Probes of Repulsive Singularities in N = 2 SupergravityMar 26 1998Repulsive singularities (repulsons) in extended supergravity theories are investigated. These repulsive singularities are related to attractive singularities (black holes) in moduli space of extended supergravity vacua. In order to study these repulsive ... More
Gauge Symmetry Enhancement and N = 2 Supersymmetric Quantum Black Holes in Heterotic String VacuaMay 20 1997Nov 05 1997N=2 supersymmetric quantum black holes in the heterotic S-T-U model are presented. In particular three classes of axion-free quantum black holes with half the N=2, D=4 supersymmetries unbroken are considered. First, these quantum black holes are investigated ... More
Entanglement in solvable many-particle modelsSep 01 2011Lecture notes for the Brazilian School on Statistical Mechanics, Natal, Brazil, July 2011. The five lectures introduce to the description of entanglement in many-particle systems and review the ground-state entanglement features of standard solvable lattice ... More
Microlocal perverse sheavesSep 25 2002We give an explicit construction of the stack of microlocal perverse sheaves on the projective cotangent bundle of a complex manifold. Microlocal perverse sheaves will be represented as complexes of analytic ind-sheaves which have recently been studied ... More
Halo Coupling and Cleaning by a Space Charge Resonance in High Intensity BeamsMay 06 2013May 07 2013We show that the difference resonance driven by the space charge pseudo-octupole of high-intensity beams not only couples the beam core emittances; it can also lead to emittance exchange in the beam halo, which is of relevance for beam loss in high intensity ... More
Spectroscopy of fermionic operators in AdS/CFTJul 25 2006Sep 20 2006We compute the spectrum of color-singlet fermionic operators in the N=2 gauge theory on intersecting D3 and D7-branes using the AdS/CFT correspondence. The operator spectrum is found analytically by solving the equations for the dual D7-brane fluctuations. ... More
A New Kalman Filter Model for Nonlinear Systems Based on Ellipsoidal BoundingFeb 08 2018In this paper, a new filter model called set-membership Kalman filter for nonlinear state estimation problems was designed, where both random and unknown but bounded uncertainties were considered simultaneously in the discrete-time system. The main loop ... More
Computational Complexity Analysis of Multi-Objective Genetic ProgrammingMar 22 2012The computational complexity analysis of genetic programming (GP) has been started recently by analyzing simple (1+1) GP algorithms for the problems ORDER and MAJORITY. In this paper, we study how taking the complexity as an additional criteria influences ... More
Changing minds about electric cars: An empirically grounded agent-based modeling approachMay 23 2014Aug 26 2014The diffusion of electric vehicles (EVs) is considered an effective policy strategy to meet greenhouse gas reduction targets. For large-scale adoption, however, demand-side oriented policy measures are required, based on consumers transport needs, values ... More
Elastic Electron Scattering from Light NucleiAug 14 2002The charge and magnetic form factors of light nuclei, mainly for mass numbers A<=4, provide a sensitive test of our understanding of nuclei. A number of "exact" calculations of the wave functions starting from the nucleon-nucleon interaction are available. ... More
Conics Touching a Quartic Surface with 13 NodesFeb 22 1996Motivated by questions occuring in the construction of certain twistor spaces the parameter space of conics tangent to a given quartic is investigated. For a given real quartic surface in complex $\PP ^3$ that has exactly 13 ordinary nodes as singularities ... More
Boundary structure constants for the A-series Virasoro minimal modelsNov 19 1998Jun 04 1999We consider A-series modular invariant Virasoro minimal models on the upper half plane. From Lewellen's sewing constraints a necessary form of the bulk and boundary structure constants is derived. Necessary means that any solution can be brought to the ... More
Valence of complex-valued planar harmonic functionsJan 26 2004The valence of a function $f$ at a point $w$ is the number of distinct, finite solutions to $f(z) = w$. Let $f$ be a complex-valued harmonic function in an open set $R \subseteq \mathbb{C}$. Let $S$ denote the critical set of $f$ and $C(f)$ the global ... More
Constructing highly arc transitive digraphs using a layerwise direct productNov 04 2011Nov 09 2011We introduce a construction of highly arc transitive digraphs using a layerwise direct product. This product generalizes some known classes of highly arc transitive digraphs but also allows to construct new such. We use the product to obtain counterexamples ... More
Convergence Types and Rates in Generic Karhunen-Loève Expansions with Applications to Sample Path PropertiesMar 05 2014Sep 29 2014We establish a Karhunen-Lo`eve expansion for generic centered, second order stochastic processes, which does not rely on topological assumptions. We further investigate in which norms the expansion converges and derive exact average rates of convergence ... More
A braided monoidal category for free super-bosonsSep 25 2012Feb 21 2014The chiral conformal field theory of free super-bosons is generated by weight one currents whose mode algebra is the affinisation of an abelian Lie super-algebra h with non-degenerate super-symmetric pairing. The mode algebras of a single free boson and ... More
Structure constants for the D-series Virasoro minimal modelsAug 05 1999Aug 14 2000In this paper expressions are given for the bulk and boundary structure constants of D-series Virasoro minimal models on the upper half plane. It is the continuation of an earlier work on the A-series. The solution for the boundary theory is found first ... More
On the reduced density matrix for a chain of free electronsMar 01 2004Jun 26 2004The properties of the reduced density matrix describing an interval of N sites in an infinite chain of free electrons are investigated. A commuting operator is found for arbitrary filling and also for open chains. For a half filled periodic chain it is ... More
Calculation of reduced density matrices from correlation functionsDec 30 2002It is shown that for solvable fermionic and bosonic lattice systems, the reduced density matrices can be determined from the properties of the correlation functions. This provides the simplest way to these quantities which are used in the density-matrix ... More
Green's formulas for cone differential operatorsNov 04 2003Green's formulas for elliptic cone differential operators are established. This is done by an accurate description of the maximal domain of an elliptic cone differential operator and its formal adjoint, thereby utilizing the concept of a discrete asymptotic ... More
The Evolutionary Process of Image Transition in Conjunction with Box and Strip MutationAug 05 2016Evolutionary algorithms have been used in many ways to generate digital art. We study how evolutionary processes are used for evolutionary art and present a new approach to the transition of images. Our main idea is to define evolutionary processes for ... More
Quasi-random Agents for Image Transition and AnimationOct 20 2017Quasi-random walks show similar features as standard random walks, but with much less randomness. We utilize this established model from discrete mathematics and show how agents carrying out quasi-random walks can be used for image transition and animation. ... More
Symmetry breaking and phase coexistence in a driven diffusive two-channel systemJun 12 2001We consider classical hard-core particles moving on two parallel chains in the same direction. An interaction between the channels is included via the hopping rates. For a ring, the stationary state has a product form. For the case of coupling to two ... More
A Monoidal Category for Perturbed Defects in Conformal Field TheoryApr 07 2009Nov 25 2009Starting from an abelian rigid braided monoidal category C we define an abelian rigid monoidal category C_F which captures some aspects of perturbed conformal defects in two-dimensional conformal field theory. Namely, for V a rational vertex operator ... More
Worldsheet operator product expansions and p-point functions in AdS3/CFT2Jun 29 2011Oct 14 2011We construct the operator product expansions (OPE) of the chiral primary operators in the worldsheet theory for strings on AdS_3 x S^3 x T^4. As an interesting application, we will use the worldsheet OPEs to derive a recursion relation for a particular ... More
Color Transparency at ELFEDec 11 1996We review the presentations given in the Color Transparency parallel session held during the second ELFE workshop.
On the Relation between Hybrid and Pure Spinor String TheoryDec 14 2009In this paper we revisit Berkovits' pure spinor formalism in lower dimensions. We are particularly interested in relating a six-dimensional pure spinor action previously constructed in the literature to other superstring formalisms. In order to gain some ... More
Influence of inherent structure shear stress of supercooled liquids on their shear moduliApr 13 2015Configurations of supercooled liquids residing in their local potential minimum (i.e. in their inherent structure, IS) were found to support a non-zero shear stress. This IS stress was attributed to the constraint to the energy minimization imposed by ... More
From Poincare to affine invariance: How does the Dirac equation generalize?Nov 26 2001May 30 2002A generalization of the Dirac equation to the case of affine symmetry, with SL(4,R) replacing SO(1,3), is considered. A detailed analysis of a Dirac-type Poincare-covariant equation for any spin j is carried out, and the related general interlocking scheme ... More
Expansion of a spherical dust gas -- the cosmological conundrumAug 14 2015Nov 29 2015The universe is viewed as a dust gas filling a sphere and floating in infinite empty space. Einstein's gravitational equations are applied to this case together with appropriate boundary values. The equations are solved for initial conditions chosen so ... More
Casimir Terms and Shape Instabilities for Two-Dimensional Critical SystemsMar 04 1996We calculate the universal part of the free energy of certain finite two- dimensional regions at criticality by use of conformal field theory. Two geometries are considered: a section of a circle ("pie slice") of angle \phi and a helical staircase of ... More
Evaluation of the proton charge radius from e-p scatteringMay 11 2015In light of the proton radius puzzle, the discrepancy between measurements of the proton charge radius from muonic hydrogen and those from electronic hydrogen and electron-proton scattering measurements, we reexamine the charge radius extractions from ... More
Entanglement in a periodic quenchMar 18 2008Apr 16 2008We consider a chain of free electrons with periodically switched dimerization and study the entanglement entropy of a segment with the remainder of the system. We show that it evolves in a stepwise manner towards a value proportional to the length of ... More
Improved Classification Rates under Refined Margin ConditionsOct 28 2016Jan 17 2018In this paper we present a simple partitioning based technique to refine the statistical analysis of classification algorithms. The core of our idea is to divide the input space into two parts such that the first part contains a suitable vicinity around ... More
Gaugino Condensation in the Chiral and Linear Representation of the DilatonDec 09 1994Dec 09 1994String effective theories with N=1 supersymmetry in four dimensions are subject of the discussion. Gaugino condensation in the chiral representation of the dilaton is reviewed in the truncated formalism in the $U_{K}(1)$-superspace. Using the supersymmetric ... More
Nonequilibrium Thermodynamics of the Soft Glassy Rheology ModelApr 14 2014The Soft Glassy Rheology (SGR) model is a mesoscopic framework which proved to be very successful in describing flow and deformation of various amorphous materials phenomenologically (e.g. pastes, slurries, foams etc). In this paper, we cast SGR in a ... More
Parametrically excited surface waves in magnetic fluids: observation of domain structuresMay 29 1998Observations of parametrically excited surface waves in a magnetic fluid are presented. Under the influence of a magnetic field these waves have a non--monotonic dispersion relation, which leads to a richer behavior than in ordinary liquids. We report ... More
Magnetic Faraday-InstabilityMay 29 1998In a magnetic fluid parametrically driven surface waves can be excited by an external oscillating magnetic field. A static magnetic field changes the restoring forces and damping coefficients of the various surface waves. This property enables the excitation ... More
An SVM-like Approach for Expectile RegressionJul 14 2015Expectile regression is a nice tool for investigating conditional distributions beyond the conditional mean. It is well-known that expectiles can be described with the help of the asymmetric least square loss function, and this link makes it possible ... More
Subleading contributions from instanton corrections in N = 2 supersymmetric black hole entropyFeb 24 1997We present subleading corrections to the N=2 supersymmetric black hole entropy. These subleading contributions correspond to instanton corrections of the Type II string theory. In particular we consider an axion free black hole solution of low-energy ... More
Optimal Learning with Anisotropic Gaussian SVMsOct 04 2018This paper investigates the nonparametric regression problem using SVMs with anisotropic Gaussian RBF kernels. Under the assumption that the target functions are resided in certain anisotropic Besov spaces, we establish the almost optimal learning rates, ... More
Nuclear binding, correlations and the origin of EMC effectJul 19 2012Recent data for the slope of the EMC-ratio in the intermediate $x$-region for {\em light} nuclei, with $3 \leq A \leq 12$, have the potential to shed new light on the origin of the EMC effect. Here we study the role of nuclear binding using the scaling ... More
Optimal Learning Rates for Localized SVMsJul 23 2015One of the limiting factors of using support vector machines (SVMs) in large scale applications are their super-linear computational requirements in terms of the number of training samples. To address this issue, several approaches that train SVMs on ... More
Nonadiabatic tunneling in circularly polarized laser fields. III. Comparison with experimentApr 17 2013We compare results of the recent experiment by Herath et al [T. Herath, L. Yan, S. K. Lee, and W. Li, Phys. Rev. Lett. 109, 043004 (2012)] on strong-field nonadiabatic tunneling in circularly polarized laser fields with the original predictions of our ... More
Nonadiabatic tunneling in circularly polarized laser fields: Derivation of formulasNov 23 2012We provide detailed analysis of strong field ionization of degenerate valence p orbitals by circularly polarized fields. Our analytical approach is conceptually equivalent to the Perelomov, Popov, and Terent'ev (PPT) theory and is virtually exact for ... More
Surface and bulk entanglement in free-fermion chainsDec 13 2013Apr 14 2014We consider free-fermion chains where full and empty parts are connected by a transition region with narrow surfaces. This can be caused by a linear potential or by time evolution from a step-like initial state. Entanglement spectra, entanglement entropies ... More
Reduced density matrices and entanglement entropy in free lattice modelsJun 09 2009Sep 01 2009We review the properties of reduced density matrices for free fermionic or bosonic many-particle systems in their ground state. Their basic feature is that they have a thermal form and thus lead to a quasi-thermodynamic problem with a certain free-particle ... More
Cardy algebras and sewing constraints, IJul 21 2008Oct 26 2009This is part one of a two-part work that relates two different approaches to two-dimensional open-closed rational conformal field theory. In part one we review the definition of a Cardy algebra, which captures the necessary consistency conditions of the ... More
Local chiral EFT potentials in nuclei and neutron matter: results and issuesMar 12 2019In recent years, the combination of advanced quantum Monte Carlo (QMC) methods and local interactions derived from chiral effective field theory (EFT) has been shown to provide a versatile and systematic approach to nuclear systems. Calculations at next-to-next-to-leading ... More
Rotational invariance conditions in elasticity, gradient elasticity and its connection to isotropyMar 19 2016Aug 05 2016For homogeneous higher gradient elasticity models we discuss frame-indifference and isotropy requirements. To this end, we introduce the notions of local versus global SO(3)-invariance and identify frame-indifference (traditionally) with global left SO(3)-invariance ... More
Thermodynamics of a rotating black hole in minimal five-dimensional gauged supergravityFeb 24 2015In this article we study the thermodynamics of a general non-extremal rotating black hole in minimal five-dimensional gauged supergravity. We analyse the entropy-temperature diagram and the free energy. Additionally we consider the thermodynamic stability ... More
Incremental and Fully Dynamic Subgraph Connectivity For Emergency PlanningNov 16 2016During the last 10 years it has become popular to study dynamic graph problems in a emergency planning or sensitivity setting: Instead of considering the general fully dynamic problem, we only have to process a single batch update of size $d$; after the ... More
Realizing arithmetic invariants of hyperbolic 3-manifoldsJul 30 2011These are mostly expository notes based on the course of lectures on arithmetic invariants of hyperbolic manifolds given at the workshop associated with the final "Volume Conference," held at Columbia University, June 2009. Some new results are included. ... More
Stationary Equilibria of Mean Field Games with Finite State and Action SpaceJan 25 2019Mean field games formalize dynamic games with a continuum of players and explicit interaction, where the players can have heterogeneous states. As they additionally yield approximate equilibria of corresponding $N$-player games, they are of great interest ... More
About the equivalence of divisor classes on hyperelliptic curves and a quotient of linear forms by an algebraic group actionApr 26 2006For a hyperelliptic curve of genus $g$, a divisor in general position of degree $g+1$ is given by polynomial equations. There is an action from an algebraic group on the representations of divisors by polynomials which fixes divisor classes. This structure ... More
Playing jeu de taquin on d-complete posetsJan 15 2014Jan 23 2014Using a modified version of jeu de taquin, Novelli, Pak and Stoyanovskii gave a bijective proof of the hook-length formula for counting standard Young tableaux of fixed shape. In this paper we consider a natural extension of jeu de taquin to arbitrary ... More
Secondary Theories for etale groupoidsJan 24 2012Generalizing Karoubi's multiplicative K-theory and multiplicative cohomology groups for smooth manifolds we define secondary theories and characteristic classes for smooth etale groupoids. As special cases we obtain versions of the groups of differential ... More
Characterization of the 3D microstructure of Ibuprofen tablets by means of synchrotron tomographyJun 12 2018We present a methodology to characterize the 3D microstructure of Ibuprofen tablets, which strongly influences the strength and solubility kinetics of the final formulation, by means of synchrotron tomography. A physically coherent trinarization for greyscale ... More
A Feature-Based Analysis on the Impact of Set of Constraints for e-Constrained Differential EvolutionJun 23 2015Different types of evolutionary algorithms have been developed for constrained continuous optimization. We carry out a feature-based analysis of evolved constrained continuous optimization instances to understand the characteristics of constraints that ... More
A Feature-Based Comparison of Evolutionary Computing Techniques for Constrained Continuous OptimisationSep 23 2015Evolutionary algorithms have been frequently applied to constrained continuous optimisation problems. We carry out feature based comparisons of different types of evolutionary algorithms such as evolution strategies, differential evolution and particle ... More
Regular geodesic normal forms in virtually abelian groupsFeb 24 1997Cannon has given an example of a virtually abelian group and a generating set where the full language of geodesics is not regular. We describe a virtually abelian group and a generating set so that no regular language of geodesics surjects to the group. ... More
Étale homotopy types of moduli stacks of polarised abelian schemesDec 23 2015We determine the Artin-Mazur \'etale homotopy types of moduli stacks of polarised abelian schemes using transcendental methods and derive some arithmetic properties of the \'etale fundamental groups of these moduli stacks. Finally we analyse the Torelli ... More
Finite top-mass effects in gluon-induced Higgs production with a jet-veto at NNLOAug 28 2014Effects from a finite top quark mass on the H+n-jet cross section through gluon fusion are studied for $n=0/n\ge 1$ at NNLO/NLO QCD. For this purpose, sub-leading terms in $1/m_t$ are calculated. We show that the asymptotic expansion of the jet-vetoed ... More
On the Humble Origins of the Brownian Entropic ForceJun 17 2015Recognition that certain forces arising from the averaging of the multiple impacts of a solute particle by the surrounding solvent particles undergoing random thermal motion can be of an entropic nature has led to the incorporation of these forces and ... More
Entropic Elasticity of Weakly Perturbed PolymersJan 22 2001Taking into account the nonequivalence of fixed-force and fixed-length ensembles in the weak-force regime, equations of state are derived that describe the equilibrium extension or compression of an ideal Gaussian polymer chain in response to an applied ... More
Étale homotopy types of moduli stacks of polarised abelian schemesDec 23 2015Dec 08 2016We determine the Artin-Mazur \'etale homotopy types of moduli stacks of polarised abelian schemes using transcendental methods and derive some arithmetic properties of the \'etale fundamental groups of these moduli stacks. Finally we analyse the Torelli ... More
Duality Invariant Non-Extreme Black Holes in Toroidally Compactified String TheoryMar 19 1997Apr 02 1997We present duality invariant structure of the thermodynamic quantities of non-extreme black hole solutions of torodially compactified Type II (M-theory) and heterotic string in five and four dimensions. These quantities are parameterized by duality invariant ... More
On-Mass-Shell Gaugino Condensation in Z_{N} Orbifold CompactificationsOct 05 1995We discuss non-perturbative aspects of string effective field theories with N=1 supersymmetry in four dimensions. By the use of a scalar potential, which is on-shell invariant under the supersymmetric duality of the dilaton, we study gaugino condensation ... More
Spin-k/2-spin-k/2 SU(2) two-point functions on the torusNov 01 2012We discuss a class of two-point functions on the torus of primary operators in the SU(2) Wess-Zumino-Witten model at integer level k. In particular, we construct an explicit expression for the current blocks of the spin-k/2-spin-k/2 torus two-point functions ... More
Growing Live Disks Within Cosmologically Assembling Asymmetric Halos: Washing Out the Halo ProlatenessMar 17 2006We study the growth of galactic disks in live triaxial DM halos. The halos have been assembled through constrained realizations method and evolved from the linear regime using cosmological simulations. The `seed' disks have been inserted at redshift z=3 ... More
A discontinuity in the low-mass initial mass functionAug 13 2007Dec 10 2007The origin of brown dwarfs (BDs) is still an unsolved mystery. While the standard model describes the formation of BDs and stars in a similar way recent data on the multiplicity properties of stars and BDs show them to have different binary distribution ... More
Hypothesis Testing for Validation and CertificationFeb 26 2013We develop a hypothesis testing framework for the formulation of the problems of 1) the validation of a simulation model and 2) using modeling to certify the performance of a physical system. These results are used to solve the extrapolative validation ... More
Estimating conditional quantiles with the help of the pinball lossFeb 10 2011The so-called pinball loss for estimating conditional quantiles is a well-known tool in both statistics and machine learning. So far, however, only little work has been done to quantify the efficiency of this tool for nonparametric approaches. We fill ... More
The sweeping rate in diffusion-mediated reactions on dust grain surfacesApr 03 2006A prominent chemical reaction in interstellar clouds is the formation of molecular hydrogen by recombination, which essentially takes place on dust grain surfaces. Analytical approaches to model such a system have hitherto neglected the spatial aspects ... More
Spin from defects in two-dimensional quantum field theoryJun 24 2015We build two-dimensional quantum field theories on spin surfaces starting from theories on oriented surfaces with networks of topological defect lines and junctions. The construction uses a combinatorial description of the spin structure in terms of a ... More
Orbifold completion of defect bicategoriesOct 23 2012Jun 13 2014Orbifolds of two-dimensional quantum field theories have a natural formulation in terms of defects or domain walls. This perspective allows for a rich generalisation of the orbifolding procedure, which we study in detail for the case of topological field ... More
Towards an understanding of lineage specification in hematopoietic stem cells: A mathematical model for the interaction of transcription factors GATA-1 and PU.1Jan 18 2006In addition to their self-renewal capabilities, hematopoietic stem cells guarantee the continuous supply of fully differentiated, functional cells of various types in the peripheral blood. The process which controls differentiation into the different ... More
Energy estimates for weakly hyperbolic systems of the first orderNov 03 2003For a class of weakly hyperbolic systems of the form D_t - A(t,x,D_x), where A(t,x,D_x) is a first-order pseudodifferential operator whose principal symbol degenerates like t^{l_*} at time t=0, for some integer l_* \geq 1, well-posedness of the Cauchy ... More
A topological view on algebraic computation modelsFeb 25 2016We investigate the topological aspects of some algebraic computation models, in particular the BSS-model. Our results can be seen as bounds on how different BSS-computability and computability in the sense of computable analysis can be. The framework ... More
Atiyah sequences, connections and Chern-Weil theory for algebraic and differentiable stacksNov 19 2013Nov 26 2013We construct connections and characteristic forms for principal bundles over groupoids and stacks in the differentiable, holomorphic and algebraic category using Atiyah sequences associated to transversal tangential distributions.
The Packing While Traveling ProblemDec 30 2015This paper introduces the Packing While Traveling problem as a new non-linear knapsack problem. Given are a set of cities that have a set of items of distinct profits and weights and a vehicle that may collect the items when visiting all the cities in ... More
A complexity theorem for the Novelli-Pak-Stoyanovskii algorithmJun 21 2013We describe two aspects of the behaviour of entries of tabloids during the application of the Novelli-Pak-Stoyanovskii algorithm. We derive two theorems which both contain a generalized version of a conjecture by Krattenthaler and M\"uller concerning ... More
A short proof that positive generation implies the Hanna Neumann ConjectureFeb 13 2007We give a very short proof that a subgroup of a free group that is positively generated cannot be part of a counterexample to the Generalized Hanna Neumann Conjecture.
A kinetic reaction model: decay to equilibrium and macroscopic limitMar 19 2015We propose a kinetic relaxation-model to describe a generation-recombination reaction of two species. The decay to equilibrium is studied by two recent methods for proving hypocoercivity of the linearized equations. Exponential decay of small perturbations ... More
Ideal-Chain Collapse in BiopolymersNov 29 2000Dec 18 2000A conceptual difficulty in the Hooke's-law description of ideal Gaussian polymer-chain elasticity is sometimes apparent in analyses of experimental data or in physical models designed to simulate the behavior of biopolymers. The problem, the tendency ... More
Phase Diagram for Unzipping DNA Using a Bond-Force CriterionJan 29 2002Using the criterion that the mechanical unzipping transition in a bound homopolymer is triggered when the average force exerted by the single unbound strands on the first base pair in the bound section exceeds the force binding the pair together, the ... More
Quantitative perturbative study of convergence to equilibrium for collisional kinetic models in the torusJul 21 2006For a general class of linear collisional kinetic models in the torus, including in particular the linearized Boltzmann equation for hard spheres, the linearized Landau equation with hard and moderately soft potentials and the semi-classical linearized ... More
Enriching Existing Test Collections with OXPathJun 21 2017Extending TREC-style test collections by incorporating external resources is a time consuming and challenging task. Making use of freely available web data requires technical skills to work with APIs or to create a web scraping program specifically tailored ... More
Some consequences of thermodynamic feasibility for the multistability and injectivity in chemical reaction networksMar 02 2014May 21 2014The result of this paper is the elucidation of the consequences for the chemical reaction network theory under the assumption of feasibility with respect to thermodynamic constraints. Thermodynamic feasible reaction networks limit the amount of "allowed" ... More