Browsing 2017 by Title
Now showing items 120 of 36

Abstract Bivariant Cuntz Semigroups
[OWP201704] (Mathematisches Forschungsinstitut Oberwolfach, 20170213)We show that abstract Cuntz semigroups form a closed symmetric monoidal category. Thus, given Cuntz semigroups $S$ and $T$, there is another Cuntz semigroup $((S,T))$ playing the role of morphisms from $S$ to $T$. Applied ... 
Analysis and Simulation of a New MultiComponent TwoPhase Flow Model with Phase Transitions and Chemical Reactions
[OWP201708] (Mathematisches Forschungsinstitut Oberwolfach, 20170315)A classII model for multicomponent mixtures recently introduced in D. Bothe, W. Dreyer, Continuum thermodynamics of chemically reacting fluid mixtures, Acta Mech., 226 (2015), 1757–1805 is investigated for simple mixtures. ... 
Bredon Cohomology and Robot Motion Planning
[OWP201734] (Mathematisches Forschungsinstitut Oberwolfach, 20171129)In this paper we study the topological invariant ${\sf {TC}}(X)$ reflecting the complexity of algorithms for autonomous robot motion. Here, $X$ stands for the configuration space of a system and ${\sf {TC}}(X)$ is, roughly, ... 
Cocycle Superrigidity and Group Actions on Stably Finite C*Algebras
[OWP201701] (Mathematisches Forschungsinstitut Oberwolfach, 20170117)Let $\Lambda $ be a countably infinite property (T) group, and let $D$ be UHFalgebra of infinite type. We prove that there exists a continuum of pairwise non (weakly) cocycle conjugate, strongly outer actions of $\Lambda ... 
The Colored Jones Polynomial and KontsevichZagier Series for Double Twist Knots
[OWP201729] (Mathematisches Forschungsinstitut Oberwolfach, 20171020)Using a result of Takata, we prove a formula for the colored Jones polynomial of the double twist knots $K_{(m,p)}$ and $K_{(m,p)}$ where $m$ and $p$ are positive integers. In the $(m,p)$ case, this leads to new ... 
Composition of Irreducible Morphisms in Coils
[OWP201732] (Mathematisches Forschungsinstitut Oberwolfach, 20171030)We study the nonzero composition of n irreducible morphisms between modules lying in coils in relation with the powers of the radical of their module category. 
Counting Curves on Toric Surfaces Tropical Geometry & the Fock Space
[OWP201718] (Mathematisches Forschungsinstitut Oberwolfach, 20170717)We study the stationary descendant Gromov–Witten theory of toric surfaces by combining and extending a range of techniques – tropical curves, floor diagrams, and Fock spaces. A correspondence theorem is established between ... 
Detecting Ineffective Features for Pattern Recognition
[OWP201726] (Mathematisches Forschungsinstitut Oberwolfach, 20171017)For a binary classification problem, the hypothesis testing is studied, that a component of the observation vector is not effective, i.e., that component carries no information for the classification. We introduce nearest ... 
Exact Rate of Convergence of kNearestNeighbor Classification Rule
[OWP201725] (Mathematisches Forschungsinstitut Oberwolfach, 20171016)A binary classification problem is considered. The excess error probability of the knearest neighbor classification rule according to the error probability of the Bayes decision is revisited by a decomposition of the ... 
Experimenting with Zariski Dense Subgroups
[OWP201731] (Mathematisches Forschungsinstitut Oberwolfach, 20171028)We give a method to describe all congruence images of a finitely generated Zariski dense group $H\leq SL(n, \mathbb{R})$. The method is applied to obtain efficient algorithms for solving this problem in odd prime degree ... 
An Extension Problem and Trace Hardy Inequality for the Sublaplacian on HType Groups
[OWP201720] (Mathematisches Forschungsinstitut Oberwolfach, 20170724)In this paper we study the extension problem for the sublaplacian on a Htype group and use the solutions to prove trace Hardy and Hardy inequalities for fractional powers of the sublaplacian. 
Freeness of MultiReflection Arrangements via Primitive Vector Fields
[OWP201710] (Mathematisches Forschungsinstitut Oberwolfach, 20170420)In 2002, Terao showed that every reflection multiarrangement of a real reflection group with constant multiplicity is free by providing a basis of the module of derivations. We first generalize Terao's result to ... 
GAP Functionality for Zariski Dense Groups
[OWP201722] (Mathematisches Forschungsinstitut Oberwolfach, 20170914)In this document we describe the functionality of GAP [4] routines for Zariski dense or arithmetic groups that are developed in [1, 2, 3]. The research underlying the software was supported through the programme "Research ... 
Geometry of Free Loci and Factorization of Noncommutative Polynomials
[OWP201723] (Mathematisches Forschungsinstitut Oberwolfach, 20171002)The free singularity locus of a noncommutative polynomial f is defined to be the sequence $Z_n(f)=\{X\in M_n^g : \det f(X)=0\}$ of hypersurfaces. The main theorem of this article shows that f is irreducible if and only if ... 
Gradient Canyons, Concentration of Curvature, and Lipschitz Invariants
[OWP201735] (Mathematisches Forschungsinstitut Oberwolfach, 20171213)We find new biLipschitz invariants of holomorphic functions of two variables by using the gradient canyons and by combining analytic and geometric viewpoints on the concentration of curvature. 
Holonomy Groups of $G_2^*$Manifolds
[OWP201707] (Mathematisches Forschungsinstitut Oberwolfach, 20170307)We classify the holonomy algebras of manifolds admitting an indecomposable torsion free $G_2^*$structure, i.e. for which the holonomy representation does not leave invariant any proper nondegenerate subspace. We realize ... 
The Index of Singular Zeros of Harmonic Mappings of AntiAnalytic Degree One
[OWP201703] (Mathematisches Forschungsinstitut Oberwolfach, 20170202)We study harmonic mappings of the form $f(z) = h(z)  \overline{z}$, where $h$ is an analytic function. In particular we are interested in the index (a generalized multiplicity) of the zeros of such functions. Outside the ... 
Inductive Freeness of Ziegler’s Canonical Multiderivations for Reflection Arrangements
[OWP201714] (Mathematisches Forschungsinstitut Oberwolfach, 20170430)Let $A$ be a free hyperplane arrangement. In 1989, Ziegler showed that the restriction $A''$ of $A$ to any hyperplane endowed with the natural multiplicity is then a free multiarrangement. We initiate a study of the stronger ... 
Linear Syzygies, Hyperbolic Coxeter Groups and Regularity
[OWP201715] (Mathematisches Forschungsinstitut Oberwolfach, 20170524)We build a new bridge between geometric group theory and commutative algebra by showing that the virtual cohomological dimension of a Coxeter group is essentially the regularity of the Stanley–Reisner ring of its nerve. ... 
Locally Compact Abelian pGroups Revisited
[OWP201706] (Mathematisches Forschungsinstitut Oberwolfach, 20170303)Even though the structure of locally compact abelian groups is generally considered to be rather thoroughly known through a wealth of publications, one keeps encountering corners that are not elucidated in uptodate ...