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Global gradient estimates for the $p(\cdot)$-LaplacianDec 19 2013We consider Calder\'on-Zygmund type estimates for the non-homogeneous $p(\cdot)$-Laplacian system $ -\text{div}(|D u|^{p(\cdot)-2} Du) = -\text{div}(|G|^{p(\cdot)-2} G),$ where $p$ is a variable exponent. We show that $|G|^{p(\cdot)} \in L^q(\mathbb{R}^n)$ ... More

Existence, uniqueness and optimal regularity results for very weak solutions to nonlinear elliptic systemsJan 30 2016We establish existence, uniqueness and optimal regularity results for very weak solutions to certain nonlinear elliptic boundary value problems. We introduce structural asymptotic assumptions of Uhlenbeck type on the nonlinearity, which are sufficient ... More

Convex Hull Property and Maximum Principle for Finite Element Minimisers of General Convex FunctionalsFeb 01 2013The convex hull property is the natural generalization of maximum principles from scalar to vector valued functions. Maximum principles for finite element approximations are often crucial for the preservation of qualitative properties of the respective ... More

Optimal error estimate for semi-implicit space-time discretization for the equations describing incompressible generalized Newtonian fluidsJul 29 2013In this paper we study the numerical error arising in the space-time approximation of unsteady generalized Newtonian fluids which possess a stress-tensor with $(p,\delta)$-structure. A semi-implicit time-discretization scheme coupled with conforming inf-sup ... More

Finite element approximation of steady flows of incompressible fluids with implicit power-law-like rheologyApr 10 2012Oct 28 2013We develop the analysis of finite element approximations of implicit power-law-like models for viscous incompressible fluids. The Cauchy stress and the symmetric part of the velocity gradient in the class of models under consideration are related by a, ... More

Existence of Weak Solutions for a Diffuse Interface Model of Non-Newtonian Two-Phase FlowsFeb 13 2013We consider a phase field model for the flow of two partly miscible incompressible, viscous fluids of Non-Newtonian (power law) type. In the model it is assumed that the densities of the fluids are equal. We prove existence of weak solutions for general ... More

Instance optimality of the adaptive maximum strategyJun 03 2013Nov 21 2014In this paper, we prove that the standard adaptive finite element method with a (modified) `maximum marking strategy' is `instance optimal' for the `total error', being the sum of the energy error and the oscillation. This result will be derived in the ... More

Higher Order Calderon-Zygmund Estimates for the p-Laplace EquationApr 06 2019The paper is concerned with higher order Calderon-Zygmund estimates for the $p$-Laplace equation $$ -\textrm{div}(A(\nabla u)) := -\textrm{div}{(|\nabla u|^{p-2}\nabla u)}=-\textrm{div} F, \qquad 1<p<\infty. $$ We are able to transfer local interior Besov ... More

New Examples on Lavrentiev Gap Using FractalsJun 11 2019Jun 13 2019Zhikov showed 1986 with his famous checkerboard example that functionals with variable exponents can have a Lavrentiev gap. For this example it was crucial that the exponent had a saddle point whose value was exactly the dimension. In 1997 he extended ... More

Partial regularity for minimizers of quasiconvex functionals with general growthMay 11 2012We prove a partial regularity result for local minimizers of quasiconvex variational integrals with general growth. The main tool is an improved A-harmonic approximation, which should be interesting also for classical growth.

The inverse of the divergence operator on perforated domains with applications to homogenization problems for the compressible Navier-Stokes systemSep 30 2015Apr 04 2016We study the inverse of the divergence operator on a domain $\Omega \subset R^3$ perforated by a system of tiny holes. We show that such inverse can be constructed on the Lebesgue space $L^p(\Omega)$ for any $1< p < 3$, with a norm independent of perforation, ... More

A Relaxed Kačanov Iteration for the $p$-Poisson ProblemFeb 13 2017In this paper, we introduce an iterative linearization scheme that allows to approximate the weak solution of the $p$-Poisson problem \begin{align*} -\operatorname{div}(|\nabla u|^{p-2}\nabla u) &= f\quad\text{in }\Omega, u&= 0\quad\text{on}\partial\Omega ... More

Unconditional stability of semi-implicit discretizations of singular flowsNov 29 2017A popular and efficient discretization of evolutions involving the singular $p$-Laplace operator is based on a factorization of the differential operator into a linear part which is treated implicitly and a regularized singular factor which is treated ... More

Regularity for parabolic systems of Uhlenbeck type with Orlicz growthMar 17 2016Oct 24 2017We study the local regularity of $p$-caloric functions or more generally of $\phi$-caloric functions. In particular, we study local solutions of non-linear parabolic systems with homogeneous right hand side, where the leading terms has Uhlenbeck structure ... More

Convergence Analysis for a Finite Element Approximation of a Steady Model for Electrorheological FluidsJul 10 2014Apr 15 2015In this paper we study the finite element approximation of systems of $p(\cdot)$-Stokes type, where $p(\cdot)$ is a (non constant) given function of the space variables. We derive --in some cases optimal-- error estimates for finite element approximation ... More

Function spaces of variable smoothness and integrabilityNov 15 2007In this article we introduce Triebel--Lizorkin spaces with variable smoothness and integrability. Our new scale covers spaces with variable exponent as well as spaces of variable smoothness that have been studied in recent years. Vector-valued maximal ... More

Campanato estimates for the generalized Stokes SystemNov 16 2012We study interior regularity of solutions of a generalized stationary Stokes problem in the plane. The main, elliptic part of the problem is given in the form div(A(Du)), where D is the symmetric part of the gradient. The model case is A(Du)=(kappa+|Du|)^{p-2}Du. ... More

Traces of functions of bounded A-variation and variational problems with linear growthJul 21 2017In this paper, we consider the space $BV^{A}(\Omega)$ of functions of bounded $A$-variation. For a given first order linear homogeneous differential operator with constant coefficients $A$, this is the space of $L^1$--functions $u:\Omega\rightarrow R^N$ ... More

The Stokes and Poisson problem in variable exponent spacesMay 15 2012We study the Stokes and Poisson problem in the context of variable exponent spaces. We prove the existence of strong and weak solutions for bounded domains with C^{1,1} boundary with inhomogenous boundary values. The result is based on generalizations ... More

Regularity for parabolic systems of Uhlenbeck type with Orlicz growthMar 17 2016May 20 2016We study the local regularity of $p$-caloric functions or more generally of $\phi$-caloric functions. In particular, we study local solutions of non-linear parabolic systems with homogeneous right hand side, where the leading term has Uhlenbeck structure ... More

New Examples on Lavrentiev Gap Using FractalsJun 11 2019Zhikov showed 1986 with his famous checkerboard example that functionals with variable exponents can have a Lavrentiev gap. For this example it was crucial that the exponent had a saddle point whose value was exactly the dimension. In 1997 he extended ... More

Trace-free Korn inequalities in Orlicz spacesMay 03 2016Necessary and sufficient conditions are exhibited for a Korn type inequality to hold between (possibly different) Orlicz norms of the gradient of vector-valued functions and of the deviatoric part of their symmetric gradients. As a byproduct of our approach, ... More

Trace-free Korn inequalities in Orlicz spacesMay 03 2016Feb 27 2017Necessary and sufficient conditions are exhibited for a Korn type inequality to hold between (possibly different) Orlicz norms of the gradient of vector-valued functions and of the deviatoric part of their symmetric gradients. As a byproduct of our approach, ... More

On the Trace Operator for Functions of Bounded $\mathbb{A}$-VariationJul 21 2017Mar 09 2019In this paper, we consider the space $\mathrm{BV}^{\mathbb A}(\Omega)$ of functions of bounded $\mathbb A$-variation. For a given first order linear homogeneous differential operator with constant coefficients $\mathbb A$, this is the space of $L^1$--functions ... More

Besov regularity of solutions to the p-Poisson equationAug 19 2014In this paper, we study the regularity of solutions to the $p$-Poisson equation for all $1<p<\infty$. In particular, we are interested in smoothness estimates in the adaptivity scale $ B^\sigma_{\tau}(L_{\tau}(\Omega))$, $1/\tau = \sigma/d+1/p$, of Besov ... More

Pointwise Calderón-Zygmund gradient estimates for the $p$-Laplace systemOct 09 2015Pointwise estimates for the gradient of solutions to the $p$-Laplace system with right-hand side in divergence form are established. They enable us to develop a nonlinear counterpart of the classical Calder\'on-Zygmund theory in terms of Calder\'on-Zygmund ... More

Global Schauder estimates for the $p$-Laplace systemMar 29 2019An optimal first-order global regularity theory, in spaces of functions defined in terms of oscillations, is established for solutions to Dirichlet problems for the $p$-Laplace equation and system, with right-hand side in divergence form. The exact mutual ... More

Solenoidal Lipschitz truncation for parabolic PDE'sSep 28 2012May 28 2013We consider functions $u\in L^\infty(L^2)\cap L^p(W^{1,p})$ with $1<p<\infty$ on a time space domain. Solutions to non-linear evolutionary PDE's typically belong to these spaces. Many applications require a Lipschitz approximation $u_\lambda$ of $u$ which ... More

Parabolic Lipschitz truncation and Caloric ApproximationJun 06 2016We develop an improved version of the parabolic Lipschitz truncation, which allows qualitative control of the distributional time derivative and the preservation of zero boundary values. As a consequence, we establish a new caloric approximation lemma. ... More

CMS results and statusOct 15 2012The CMS experiment is a multi-purpose detector successfully operated at the LHC where predominantly pp collisions take place at various centre of mass energies up to sqrt(s)=8 TeV at present. Discussed are pp collision results until end of 2011, corresponding ... More

Searches in CMSJun 24 2011Jul 08 2011We discuss the results of searches for various new physics phenomena, including supersymmetry, in pp collisions at 7 TeV delivered by the LHC and collected with the CMS detector. These results demonstrate a good understanding of the detector and backgrounds ... More

Highlights of D0 QCD related analysesSep 23 2011D0 provides a wealth of measurements conceived for probing perturbative and non-perturbative aspects of QCD, giving an accurate experimental account for Standard Model production processes including jets, leptons and photons and improving the sensitivity ... More

W/Z + jet production at the TevatronAug 03 2010Vector boson plus jet production is interesting for Higgs search, beyond the Standard Model physics and provides standard candles for calibration. This is complementary to inclusive jet production measurements which provide precision tests of perturbative ... More

Photon + jets at D0Jun 15 2009Photon plus jet production has been studied by the D0 experiment in Run II of the Fermilab Tevatron Collider at a centre of mass energy of sqrt{s}=1.96 TeV. Measurements of the inclusive photon, inclusive photon plus jet, photon plus heavy flavour jet ... More

Depth Two and the Galois CoringAug 11 2004We study the cyclic module ${}_SR$ for a ring extension $A \| B$ with centralizer $R$ and bimodule endomorphism ring $S = End {}_BA_B$. We show that if $A \| B$ is an H-separable Hopf subalgebra, then $B$ is a normal Hopf subalgebra of $A$. We observe ... More

On Effective Degrees of Freedom in the Early UniverseSep 16 2016We explore the effective degrees of freedom in the early Universe, from before the electroweak scale at a few femtoseconds after the Big Bang, until the last positrons disappeared a few minutes later. We first look at the established concepts of effective ... More

Quiescent cosmological singularitiesNov 29 2000I discuss recent work (gr-qc/0001047) on non-oscillatory singularities in four dimensional space-times with scalar field or stiff fluid matter, in the context of the BKL proposal.

Constant mean curvature foliations of simplicial flat spacetimesJul 25 2003Benedetti and Guadagnini have conjectured that the marked lenght spectrum of the constant mean curvature foliation $M_\tau$ in a 2+1 dimensional flat spacetime $V$ with compact hyperbolic Cauchy surfaces converges, in the direction of the singularity, ... More

Bel--Robinson energy and constant mean curvature foliationsJul 21 2003An energy estimate is proved for the Bel--Robinson energy along a constant mean curvature foliation in a spatially compact vacuum spacetime, assuming an $L^{\infty}$ bound on the second fundamental form, and a bound on a spacetime version of Bel--Robinson ... More

Constant mean curvature foliations of flat space--timesOct 22 2001Let $V$ be a maximal globally hyperbolic flat $n+1$--dimensional space--time with compact Cauchy surface of hyperbolic type. We prove that $V$ is globally foliated by constant mean curvature hypersurfaces $M_{\tau}$, with mean curvature $\tau$ taking ... More

Track Segments within Hadronic Showers using the CALICE AHCalJun 18 2010Using the high granular CALICE analog hadron calorimeter (AHCal) a tracking algorithm capable of identifying MIP-like tracks within hadronic showers is presented. Such an algorithm provides excellent tools for detector calibration and for studies of the ... More

Screened perturbation theory at four loopsOct 15 2008We study the thermodynamics of massless phi-fourth theory using screened perturbation theory, which is a way to systematically reorganise the perturbative series. The free energy and pressure are calculated through four loops in a double expansion in ... More

LLAMA: Leveraging Learning to Automatically Manage AlgorithmsJun 05 2013Apr 30 2014Algorithm portfolio and selection approaches have achieved remarkable improvements over single solvers. However, the implementation of such systems is often highly customised and specific to the problem domain. This makes it difficult for researchers ... More

On Effective Degrees of Freedom in the Early UniverseSep 16 2016Oct 21 2016We explore the effective degrees of freedom in the early Universe, from before the electroweak scale at a few femtoseconds after the Big Bang, until the last positrons disappeared a few minutes later. We first look at the established concepts of effective ... More

The non-microstates free entropy dimension of DT-operatorsMay 28 2003Dykema and Haagerup introduced the class of DT-operators and also showed that every DT-operator generate the von Neumann algebra generated by the free group on two generators. In this paper we prove that Voiculescu's non-microstates free entropy dimension ... More

Bipartite Multigraphs with Expander-Like PropertiesDec 06 2004A graph with vertex set V and edge set E is called a (d,c)-expander if the maximum degree of a vertex is d and, for every subset W of V that has cardinality at most |V|/2, the number of edges between vertices in W and vertices outside of W is at least ... More

Centralizers and Inverses to Induction as Equivalence of CategoriesApr 30 2005Jun 02 2005Given a ring homomorphism $B \to A$, consider its centralizer $R = A^B$, bimodule endomorphism ring $S = \End {}_BA_B$ and sub-tensor-square ring $T = (A \o_B A)^B$. Nonassociative tensoring by the cyclic modules $R_T$ or ${}_SR$ leads to an equivalence ... More

Algebraic K-theory and trace invariantsApr 21 2003The cyclotomic trace of B\"okstedt-Hsiang-Madsen, the subject of B\"okstedt's lecture at the congress in Kyoto, is a map of pro-abelian groups K_*(A) -> TR_*^.(A;p) from Quillen's algebraic K-theory to a topological refinement of Connes' cyclic homology. ... More

Semisimple Hopf algebras and their depth two Hopf subalgebrasJul 03 2008We prove that a depth two Hopf subalgebra K of a semisimple Hopf algebra H is normal (where the ground field $k$ is algebraically closed of characteristic zero). This means on the one hand that a Hopf subalgebra is normal when inducing (then restricting) ... More

Pseudo-Galois Extensions and Hopf AlgebroidsAug 22 2005Aug 21 2006A pseudo-Galois extension is shown to be a depth two extension. Studying its left bialgebroid, we construct an enveloping Hopf algebroid for the semi-direct product of groups, or more generally involutive Hopf algebras, and their module algebras. It is ... More

Anchor maps and stable modules in depth twoJun 20 2006Aug 14 2006An algebra extension A | B is right depth two if its tensor-square A\otimes_B A is in the Dress category Add A as A-B-bimodules. We consider necessary conditions for right, similarly left, D2 extensions in terms of partial A-invariance of two-sided ideals ... More

Network Rewriting I: The FoundationApr 11 2012A theory is developed which uses "networks" (directed acyclic graphs with some extra structure) as a formalism for expressions in multilinear algebra. It is shown that this formalism is valid for arbitrary PROPs (short for 'PROducts and Permutations category'), ... More

On the structure of nearly pseudo-Kähler manifoldsDec 17 2009Firstly we give a condition to split off the K"ahler factor from a nearly pseudo-K"ahler manifold and apply this to get a structure result in dimension 8. Secondly we extend the construction of nearly K"ahler manifolds from twistor spaces to negatively ... More

Multifractal tubesJul 19 2013Tube formulas refer to the study of volumes of $r$ neighbourhoods of sets. For sets satisfying some (possible very weak) convexity conditions, this has a long history. However, within the past 20 years Lapidus has initiated and pioneered a systematic ... More

Report on GR16, Session A3: Mathematical Studies of the Field EquationsApr 29 2002May 17 2002In this report, which is an extended version of that appearing in the Proceedings of GR16, I will give a summary of the main topics covered in Session A.3. on mathematical relativity at GR16, Durban. The summary is mainly based on extended abstracts submitted ... More

The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?Mar 17 2010Multi-zone chemical evolution models (CEMs), differing in the nucleosynthesis prescriptions (yields) and prescriptions of star formation, have been computed for the Milky Way. All models fit the observed O/H and Fe/H gradients well and reproduce the main ... More

The 130 GeV Fingerprint of Right-Handed Neutrino Dark MatterAug 30 2012Sep 03 2012Recently, an interesting indication for a dark matter signal in the form of a narrow line, or maybe two lines and/or an internal bremsstrahlung feature, has been found in data from the Fermi-LAT satellite detector. As recent analyses have also shown that ... More

Dark Matter Evidence, Particle Physics Candidates and Detection MethodsMay 22 2012Jun 14 2012The problem of the dark matter in the universe is reviewed. A short history of the subject is given, and several of the most obvious particle candidates for dark matter are identified. Particular focus is given to weakly interacting, massive particles ... More

Side Effects in Steering FragmentsSep 10 2011In this thesis I will give a formal definition of side effects. I will do so by modifying a system for modelling program instructions and program states, Quantified Dynamic Logic, to a system called DLAf (for Dynamic Logic with Assignments as Formulas), ... More

Determination of the strong coupling constant from inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV with the D0 experimentJun 14 2010The strong coupling constant alpha_s and its dependence on the momentum scale is determined from the p_T dependence of the inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV measured with the D0 experiment. The jet transverse momentum ... More

CP-conserving and CP-violating properties in semileptonic Bs decays with the D0 experimentAug 16 2009A search for CP violation has been performed in a sample of semileptonic Bs decays corresponding to approximately 5fb^-1 of data collected by the D0 detector in Run II at the Fermilab Tevatron collider. A time-dependent fit to the distributions of Bs ... More

Photon plus Jet Cross Sections at the TevatronApr 03 2008Photon plus jet production has been studied by the D0 and CDF experiments in Run II of the Fermilab Tevatron Collider at a center of mass energy of sqrt{s}=1.96 TeV. Measurements of the inclusive photon plus jet, di-photon and photon plus b jet cross ... More

CMS: Cosmic muons in simulation and measured dataJul 03 2011A dedicated cosmic muon Monte-Carlo event generator CMSCGEN has been developed for the CMS experiment. The simulation relies on parameterisations of the muon energy and the incidence angle, based on measured and simulated data of the cosmic muon flux. ... More

On the K-theory of the coordinate axes in the planeAug 15 2005Oct 19 2005Let k be a regular F_p-algebra, let A = k[x,y]/(xy) be the coordinate ring of the coordinate axes in the affine k-plane, and let I = (x,y) be the ideal that defines the intersection point. We evaluate the relative K-groups K_q(A,I) in terms of the groups ... More

Concept for controlled transverse emittance transfer within a linac ion beamMar 24 2011For injection of beams into circular machines with different horizontal and vertical emittance acceptance, the injection efficiency can be increased if these beams are flat, i.e. if they feature unequal transverse emittances. Generation of flat electron ... More

Points of Small Height on Semiabelian VarietiesAug 02 2018The Equidistribution Conjecture is proved for general semiabelian varieties over number fields. Previously, this conjecture was only known in the special case of almost split semiabelian varieties through work of Chambert-Loir. The general case has remained ... More

Regular singular stratified bundles and tame ramificationOct 18 2012Aug 09 2013Let X be a smooth variety over an algebraically closed field k of positive characteristic. We define and study a general notion of regular singularities for stratified bundles (i.e. O_X-coherent D_X-modules) on X without relying on resolution of singularities. ... More

Finite depth and Jacobson-Bourbaki correspondenceJul 25 2007We introduce a notion of depth three tower of three rings C < B < A with depth two ring extension A | B recovered when B = C. If A = \End B_C and B | C is a Frobenius extension, this captures the notion of depth three for a Frobenius extension in arXiv:math/0107064 ... More

Wild ramification of nilpotent coverings and coverings of bounded degreeJun 28 2016A finite \'etale map between irreducible, normal varieties is called tame, if it is tamely ramified with respect to all partial compactifications whose boundary is the support of a strict normal crossings divisor. We prove that if the Galois group of ... More

Modelling dust processing and the evolution of grain sizes in the ISM using the method of momentsJun 07 2016Interstellar dust grains do not have a single well-defined origin. Stars are demonstrably dust producers, but also efficient destroyers of cosmic dust. Dust destruction in the ISM is believed to be the result of SN shocks hitting the ambient ISM gas (and ... More

Ext and Tor on two-dimensional cyclic quotient singularitiesJan 21 2016May 05 2016Given two torus invariant Weil divisors $D$ and $D'$ on a two-dimensional cyclic quotient singularity $X$, the groups $\mathop{Ext}\nolimits^i_{X}(\mathcal{O}(D),\mathcal{O}(D'))$, $i>0$, are naturally $\mathbb{Z}^2$-graded. We interpret these groups ... More

Maximally Supersymmetric Yang-Mills Theory. The Story of N = 4 Yang-Mills TheoryNov 10 2015This is a personally colored account of the history behind N=4 Yang-Mills Theory.

Recent results of the CMS experimentAug 18 2014The CMS experiment is a multi-purpose detector successfully operated at the LHC where predominantly pp collisions take place at various centre-of-mass energies up to sqrt(s)=8 TeV so far. Several weeks per year also heavy-ion collisions take place leading ... More

Pullback of regular singular stratified bundles and restriction to curvesOct 20 2014Mar 17 2015A stratified bundle is a vector bundle which is a D-module. We show that regular singularity of stratified bundles on smooth varieties in positive characteristic is preserved by pullback and that regular singularity can be checked on curves, if the ground ... More

Local-to-global extensions of D-modules in positive characteristicNov 25 2013Oct 28 2014In "On the calculation of some differential Galois groups" (Invent. Math. 87 (1987), no. 1), Katz defines the notion of a special flat connection on the complex affine line minus the origin, and he shows that the functor which restricts a flat connection ... More

Evidence for a generalization of Gieseker's conjecture on stratified bundles in positive characteristicOct 29 2012Sep 09 2013Let X be a smooth, connected, projective variety over an algebraically closed field of positive characteristic. In "Flat vector bundles and the fundamental group in non-zero characteristics" (Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4) 2 (1975)), Gieseker ... More

Codepth Two and Related TopicsDec 30 2005Aug 21 2006A depth two extension $A \| B$ is shown to be weak depth two over its double centralizer $V_A(V_A(B))$ if this is separable over $B$. We consider various examples and non-examples of depth one and two properties. Depth two and its relationship to direct ... More

Okounkov Bodies of Complexity-One T-VarietiesAug 02 2011We compute Okounkov bodies of projective complexity-one T-varieties with respect to two types of invariant flags. In particular, we show that the latter are rational polytopes. Moreover, using results of Dave Anderson and Nathan Ilten, we briefly exhibit ... More

An in-Depth Look at Quotient ModulesMay 18 2017Oct 10 2017The coset $G$-space of a finite group and a subgroup is a fundamental module of study of Schur and others around 1930; for example, its endomorphism algebra is a Hecke algebra of double cosets. We study and review its generalization $Q$ to Hopf subalgebras, ... More

Geometric Analysis and General RelativityDec 23 2005This article discusses methods of geometric analysis in general relativity, with special focus on the role of "critical surfaces" such as minimal surfaces, marginal surface, maximal surfaces and null surfaces.

Maximal supersymmetry and exceptional groupsJun 08 2010The article is a tribute to my old mentor, collaborator and friend Murray Gell-Mann. In it I describe work by Pierre Ramond, Sung-Soo Kim and myself where we describe the N = 8 Supergravity in the light-cone formalism. We show how the Cremmer-Julia E7(7) ... More

Dissipation for Euler's Disk and a Desktop Demonstration of Coalescing Neutron StarsFeb 11 2001I show that the recent calculation of Moffatt's regarding the viscous dissipation of a spinning coin overlooked the importance of the finite width of the viscous boundary layer. My new estimates are more in accord with that observed. I also point out ... More

Slow ultrafilters and asymptotic cones of proper metric spacesOct 08 2010In this paper I present an elementary construction to prove that any proper metric space can arise as the asymptotic cone of another proper metric space. Furthermore I answer a question of Drutu and Sapir concerning slow ultrafilters.

Recent multi-wavelength campaigns in the Fermi-GST eraJul 02 2010Since 2008 the Fermi/LAT instrument has delivered highly time-resolved gamma-ray spectra and detailed variability curves for a steadily increasing number of AGN. For detailed AGN studies the Fermi/LAT data have to be combined with, and accompanied by, ... More

Algorithm Selection for Combinatorial Search Problems: A SurveyOct 30 2012The Algorithm Selection Problem is concerned with selecting the best algorithm to solve a given problem on a case-by-case basis. It has become especially relevant in the last decade, as researchers are increasingly investigating how to identify the most ... More

The MSSM with large tan(beta) beyond the decoupling limitOct 02 2009For large values of tan(beta) interesting effects arise in the MSSM due to the enhancement of down-quark self-energies. These effects are well-studied within the decoupling limit, i.e. in the limit of supersymmetric masses far above the electroweak scale. ... More

Measurement of CP violation phase phi_s and charge asymmetries in B^0_(s) decays at D0Sep 23 2008Sep 25 2008The CP violation phase phi_s and charge asymmetries in B^0_s decays have been measured by the D0 experiment in Run II of the Fermilab Tevatron Collider where proton anti-proton collisions take place at a center of mass energy of sqrt{s}=1.96 TeV. The ... More

Algebraic approach to solve $t\bar{t}$ dilepton equationsOct 07 2005Jun 18 2011The set of non-linear equations describing the Standard Model kinematics of the top quark antiqark production system in the dilepton decay channel has at most a four-fold ambiguity due to two not fully reconstructed neutrinos. Its most precise solution ... More

Searches for New Phenomena at the LHCJun 26 2012Searches for physics beyond the Standard Model (SM) with the CMS and ATLAS experiments in pp collisions at a centre of mass energy of sqrt(s)=7 TeV at the LHC are presented. The discussed results are based on data taken in 2011, making use of integrated ... More

Analytical solution of ttbar dilepton equationsMar 01 2006Jun 18 2011The top quark antiquark production system in the dilepton decay channel is described by a set of equations which is nonlinear in the unknown neutrino momenta. Its most precise and least time consuming solution is of major importance for measurements of ... More

CDF and D0 top quark cross section measurementsOct 13 2004Nov 03 2004Preliminary results of ttbar cross section measurements and single top exclusion limits of the Tevatron experiments CDF and D0 are presented. The different measurements are based on a dataset between 140 and 200 inverse pb corresponding to a data taking ... More

The D0 Silicon Track TriggerSep 01 2004The Level-2 Silicon Track Trigger preprocessor (L2 STT) of the D0 detector in Run II is described. It performs a precise reconstruction of charged particle tracks in the Central Fiber Tracker (CFT) and the Silicon Microstrip Tracker (SMT). Events with ... More

Ideal depth of QF extensionsDec 08 2010A minimum depth d^I(S --> R) is assigned to a ring homomorphism S --> R and a R-R-bimodule I. The recent notion of depth of a subring d(S,R)in a paper by Boltje-Danz-Kuelshammer is recovered when I = R and S --> R is the inclusion mapping. Ideal depth ... More

An approach to quasi-Hopf algebras via Frobenius coordinatesAug 18 2004We study quasi-Hopf algebras and their subobjects over certain commutative rings from the point of view of Frobenius algebras. We introduce a type of Radford formula involving an anti-automorphism and the Nakayama automorphism of a Frobenius algebra, ... More

Skew Hopf algebras, irreducible extensions and the pi-methodJan 15 2007Dec 28 2007To a depth two extension A | B, we associate the dual bialgebroids S := \End {}_BA_B and T := (A \o_B A)^B over the centralizer R=C_A(B). In the set-up where R is a subalgebra of B, which is quite common, two nondegenerate pairings of S and T will define ... More

The big de Rham-Witt complexJun 16 2010Dec 07 2014This paper gives a new and direct construction of the multi-prime big de Rham-Witt complex which is defined for every commutative and unital ring; the original construction by the author and Madsen relied on the adjoint functor theorem and accordingly ... More

Normal Hopf subalgebras, depth two and Galois extensionsNov 06 2004Apr 06 2005Let $S$ be the left $R$-bialgebroid of a depth two extension with centralizer $R$ as defined in math.QA/0108067. We show that the left endomorphism ring of depth two extension, not necessarily balanced, is a left $S$-Galois extension of $A^{\rm op}$. ... More

On the Whitehead spectrum of the circleOct 15 2007May 22 2008The seminal work of Waldhausen, Farrell and Jones, Igusa, and Weiss and Williams shows that the homotopy groups in low degrees of the space of homeomorphisms of a closed Riemannian manifold of negative sectional curvature can be expressed as a functor ... More

Fine and coarse multifractal zeta-functions: On the multifractal formalism for multifractal zeta-functionsNov 20 2014Multifractal analysis refers to the study of the local properties of measures and functions, and consists of two parts: the fine multifractal theory and the coarse multifractal theory. The fine and the coarse theory are linked by a web of conjectures ... More

Report on GRG18, Session A3, Mathematical Studies of the Field EquationsMar 31 2008Apr 01 2008In this report I will give a summary of some of the main topics covered in Session A3, mathematical studies of the field equations, at GRG18, Sydney. Unfortunately, due to length constraints, some of the topics covered at the session will be very briefly ... More