Results for "Lars Diening"

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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
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
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
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
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
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
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
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
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
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 Lipschitz truncation of functions of bounded variationAug 28 2019We construct a Lipschitz truncation which approximates functions of bounded variation in the area-strict metric. The Lipschitz truncation changes the original function only on a small set similar to Lusin's theorem. Previous results could only give estimates ... 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
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
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
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
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
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
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
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
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
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.
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
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
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
Uniquely separable extensionsAug 14 2018Aug 12 2019The separability tensor element of a separable extension of noncommutative rings is an idempotent when viewed in the correct endomorphism ring; so one speaks of a separability idempotent, as one usually does for separable algebras. It is proven that this ... 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
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
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
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
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
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
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
The two subset recurrent property of Markov chainsFeb 23 2016This paper proposes a new type of recurrence where we divide the Markov chains into intervals that start when the chain enters into a subset A, then sample another subset B far away from A and end when the chain again return to A. The length of these ... 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
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
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
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
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
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
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
Hopf subalgebras and tensor powers of generalized permutation modulesOct 11 2012Jun 12 2014By means of a certain module V and its tensor powers in a finite tensor category, we study a question of whether the depth of a Hopf subalgebra R of a finite-dimensional Hopf algebra H is finite. The module V is the counit representation induced from ... 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
Drift velocity and pressure monitoring of the CMS muon drift chambersJul 02 2011The drift velocity in drift tubes of the CMS muon chambers is a key parameter for the muon track reconstruction and trigger. It needs to be monitored precisely in order to detect any deviation from its nominal value. A change in absolute pressure, a variation ... More
The trapped regionJan 17 2009Jan 20 2009I will discuss some recent results on marginally outer trapped surfaces, apparent horizons, and the trapped region. A couple of applications of the results developed for marginally outer trapped surfaces to coalescence of black holes and to the characterization ... More
On the relation between mathematical and numerical relativityJul 17 2006The large scale binary black hole effort in numerical relativity has led to an increasing distinction between numerical and mathematical relativity. This note discusses this situation and gives some examples of succesful interactions between numerical ... More
The global existence problem in general relativityNov 09 1999Apr 28 2006We survey some known facts and open questions concerning the global properties of 3+1 dimensional spacetimes containing a compact Cauchy surface. We consider spacetimes with an $\ell$-dimensional Lie algebra of space-like Killing fields. For each $\ell ... More
Gravitational Radiation and Rotation of Accreting Neutron StarsApr 29 1998Recent discoveries by the Rossi X-Ray Timing Explorer indicate that most of the rapidly accreting and weakly magnetic neutron stars in the Galaxy are rotating at spin frequencies greater than 250 Hz. Remarkably, they all rotate in a narrow range of frequencies. ... More
The Angular Momentum of Accreting Neutron StarsJan 07 1998I review the rotation measurements of accreting neutron stars. Many of the highly magnetic accreting X-ray pulsars have been continuously observed with the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) since ... More
Thermonuclear Burning on Rapidly Accreting Neutron StarsSep 10 1997Neutron stars in mass-transferring binaries are accreting the hydrogen and helium rich matter from the surfaces of their companions. This article simply explains the physics associated with how that material eventually fuses to form heavier nuclei and ... More
Cosmological models and stabilityOct 07 2013Principles in the form of heuristic guidelines or generally accepted dogma play an important role in the development of physical theories. In particular, philosophical considerations and principles figure prominently in the work of Albert Einstein. As ... More
Dust in the early Universe: Evidence for non-stellar dust production or observational errors?Feb 02 2011Observations have revealed unexpectedly large amounts of dust in high-redshift galaxies and its origin is still much debated. Valiante et al. (2009, MNRAS, 397, 1661) suggested the net stellar dust production of the quasar host galaxy SDSS J1148+5251 ... More
Decoupling of beams previously coupled by effective stand-alone solenoid fringe fieldsMar 27 2014Oct 23 2014Beams passing through a solenoid fringe field experience x-y coupling and change of their eigen-emittances. As reported previously (C.~Xiao et al., Phys. Rev. ST Accel. Beams 044201, {\bf 16} 2013) constant settings of a subsequent decoupling section ... More
Uniquely separable extensionsAug 14 2018The separability tensor element of a separable extension of noncommutative rings is an idempotent when viewed in the correct endomorphism ring; so one speaks of a separability idempotent, as one usually does for separable algebras. It is proven that this ... More
Small-scale clustering of nano-dust grains in turbulent interstellar molecular clouds [Extended version]Nov 23 2018Clustering and dynamics of nano-sized particles (nano dust) is investigated using high-resolution ($1024^3$) simulations of compressible isothermal hydrodynamic turbulence, intended to mimic the conditions inside cold molecular clouds in the interstellar ... More
ICON Challenge on Algorithm SelectionNov 12 2015We present the results of the ICON Challenge on Algorithm Selection.
Dirichlet-to-Robin Operators via Composition SemigroupsSep 06 2017We show well-posedness for an evolution problem associated with the Dirichlet-to-Robin operator for certain Robin boundary data. Moreover, it turns out that the semigroup generated by the Dirichlet-to-Robin operator is closely related to a weighted semigroup ... More
The Picard Group of Simply Connected Regular Varieties and Stratified Line BundlesApr 12 2011We prove that the Picard group of a regular simply connected variety over an algebraically closed field of arbitrary characteristic is finitely generated. The main difficulty to overcome is the unavailability of resolution of singularities. From this ... More
A tower condition characterizing normalityOct 18 2013Jan 27 2014We define left relative H-separable tower of rings and continue a study of these begun by Sugano. It is proven that a progenerator extension has right depth two if and only if the ring extension together with its right endomorphism ring is a left relative ... More
Separable equivalence of rings and symmetric algebrasOct 25 2017Nov 04 2018We continue a study of separable equivalence from Hokkaido Mathematical Journal 24 (1995), 527-549. We prove that symmetric separable equivalent rings $A$ and $B$ are linked by a Frobenius bimodule ${}_AP_B$ such that $A$ is $P$-separable over $B$. Separably ... More
A Generic Framework for Diamond LemmasDec 07 2007This paper gives a generic form of the diamond lemma, which includes support for additive and topological structures of the base set, and which does not require any further structure (e.g. an associative multiplication operation) to be present. This result ... More
A Parameter Version of Forstnerič's Splitting LemmaFeb 05 2018We construct solution operators to the $\overline{\partial}$-equation that depend continuously on the domain. This is applied to derive a parameter version of Forstneri\v{c}'s splitting lemma: If both the maps and the domains they are defined on vary ... More
Depth three towers of rings and groupsMar 12 2007May 11 2007Depth three and finite depth are notions known for subfactors via diagrams and Frobenius extensions of rings via centralizers in endomorphism towers. From the point of view of depth two ring extensions, we provide a clear definition of depth three for ... More
A Homogeneous Function Constant along the Leaves of a FoliationJul 03 2018Given a smooth foliation by complex curves (locally around a point $x\in\mathbb{C}^2\setminus\{0\}$) which is "compatible" with the foliation by spheres centered at the origin, we construct a smooth real-valued function $g$ in a neighborhood of said point, ... More
A note on Galois theory for bialgebroidsJan 01 2005In this note we reduce certain proofs in \cite{KS, Karl, AMA} to depth two quasibases from one side only. This minimalistic approach leads to a characterization of Galois extensions for finite projective bialgebroids without the Frobenius extension property: ... More
Chern classes of tropical vector bundlesNov 15 2009We introduce tropical vector bundles, morphisms and rational sections of these bundles and define the pull-back of a tropical vector bundle and of a rational section along a morphism. Afterwards we use the bounded rational sections of a tropical vector ... 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
Construction of hyperboloidal initial dataMay 18 2002I describe the conformal method for constructing solutions of the hyperboloidal constraint equations as well as the conditions needed on the free data in order to have regularity up to boundary for the solutions to the constraint equations. A brief discussion ... More
Arresting Accretion Torques with Gravitational RadiationNov 30 2002Recent theoretical work has made it plausible for neutron stars (NSs) to lose angular momentum via gravitational radiation on long timescales (around Myrs) while actively accreting. The gravitational waves (GWs) can either be emitted via the excitation ... More
Hot White Dwarf Donors in Ultracompact X-Ray BinariesAug 07 2002The discovery of two accreting millisecond X-ray pulsars in binaries with 43 minute orbital periods allows for a new probe of the donor's structure. For XTE J1751-305, only a hot white dwarf (WD) can fill the Roche Lobe. A cold He WD is a possible solution ... More
Theory and Observations of Type I X-Ray Bursts from Neutron StarsJan 08 2000I review our understanding of the thermonuclear instabilities on accreting neutron stars that produce Type I X-Ray bursts. I emphasize those observational and theoretical aspects that should interest the broad audience of this meeting. The easily accessible ... More
Measuring NUMA effects with the STREAM benchmarkMar 16 2011Modern high-end machines feature multiple processor packages, each of which contains multiple independent cores and integrated memory controllers connected directly to dedicated physical RAM. These packages are connected via a shared bus, creating a system ... More