2017
2017
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Z2-Thurston Norm and Complexity of 3-Manifolds, II
[OWP-2017-36] (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-20)In this sequel to earlier papers by three of the authors, we obtain a new bound on the complexity of a closed 3-manifold, as well as a characterisation of manifolds realising our complexity bounds. As an application, we ... -
Gradient Canyons, Concentration of Curvature, and Lipschitz Invariants
[OWP-2017-35] (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-13)We find new bi-Lipschitz invariants of holomorphic functions of two variables by using the gradient canyons and by combining analytic and geometric viewpoints on the concentration of curvature. -
Bredon Cohomology and Robot Motion Planning
[OWP-2017-34] (Mathematisches Forschungsinstitut Oberwolfach, 2017-11-29)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, ... -
Experimenting with Zariski Dense Subgroups
[OWP-2017-31] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-28)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 ... -
The Varchenko Determinant of a Coxeter Arrangement
[OWP-2017-33] (Mathematisches Forschungsinstitut Oberwolfach, 2017-11-24)The Varchenko determinant is the determinant of a matrix defined from an arrangement of hyperplanes. Varchenko proved that this determinant has a beautiful factorization. It is, however, not possible to use this factorization ... -
Looking Back on Inverse Scattering Theory
[OWP-2017-24] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-05)We present an essay on the mathematical development of inverse scattering theory for time-harmonic waves during the past fifty years together with some personal memories of our participation in these events. -
GAP Functionality for Zariski Dense Groups
[OWP-2017-22] (Mathematisches Forschungsinstitut Oberwolfach, 2017-09-14)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
[OWP-2017-23] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-02)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 ... -
Composition of Irreducible Morphisms in Coils
[OWP-2017-32] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-30)We study the non-zero composition of n irreducible morphisms between modules lying in coils in relation with the powers of the radical of their module category. -
Non-Extendability of Holomorphic Functions with Bounded or Continuously Extendable Derivatives
[OWP-2017-30] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-21)We consider the spaces $H_{F}^{\infty}(\Omega)$ and $\mathcal{A}_{F}(\Omega)$ containing all holomorphic functions $f$ on an open set $\Omega \subseteq \mathbb{C}$, such that all derivatives $f^{(l)}$, $l\in F \subseteq ... -
The Colored Jones Polynomial and Kontsevich-Zagier Series for Double Twist Knots
[OWP-2017-29] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-20)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 ... -
On an Effective Variation of Kronecker’s Approximation Theorem Avoiding Algebraic Sets
[OWP-2017-28] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-19)Let $\Lambda \subset \mathbb R^n$ be an algebraic lattice, coming from a projective module over the ring of integers of a number field $K$. Let $\mathcal Z \subset \mathbb R^n$ be the zero locus of a finite collection of ... -
Review of the Methods of Reflections
[OWP-2017-27] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-18)The methods of reflections were invented to obtain approximate solutions of the motion of more than one particle in a given environment, provided that one can represent the solution for one particle rather easily. This ... -
Detecting Ineffective Features for Pattern Recognition
[OWP-2017-26] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-17)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 k-Nearest-Neighbor Classification Rule
[OWP-2017-25] (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-16)A binary classification problem is considered. The excess error probability of the k-nearest neighbor classification rule according to the error probability of the Bayes decision is revisited by a decomposition of the ... -
Reducing sub-modules of the Bergman module $\mathbb A^{(\lambda)}(\mathbb D^n)$ under the action of the symmetric group
[OWP-2017-19] (Mathematisches Forschungsinstitut Oberwolfach, 2017-07-20)The weighted Bergman spaces on the polydisc, $\mathbb A^{(\lambda)}(\mathbb D^n)$, $\lambda>0,$ splits into orthogonal direct sum of subspaces $\mathbb P_{\boldsymbol p}\big(\mathbb A^{(\lambda)}(\mathbb D^n)\big)$ indexed ... -
An Extension Problem and Trace Hardy Inequality for the Sublaplacian on H-Type Groups
[OWP-2017-20] (Mathematisches Forschungsinstitut Oberwolfach, 2017-07-24)In this paper we study the extension problem for the sublaplacian on a H-type group and use the solutions to prove trace Hardy and Hardy inequalities for fractional powers of the sublaplacian. -
Counting Curves on Toric Surfaces Tropical Geometry & the Fock Space
[OWP-2017-18] (Mathematisches Forschungsinstitut Oberwolfach, 2017-07-17)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 ... -
The Pseudo-Hyperresolution and Applications
[OWP-2017-17] (Mathematisches Forschungsinstitut Oberwolfach, 2017-07-04)Resolving objects in an abelian category by injective (projective) resolutions is a fundamental problem in mathematics, and this article aims at introducing a particular solution called “Pseudo-hyperresolutions”. This ... -
Matrix Elements of Irreducible Representations of SU(n+1) x SU(n+1) and Multivariable Matrix-Valued Orthogonal Polynomials
[OWP-2017-16] (Mathematisches Forschungsinstitut Oberwolfach, 2017-06-14)In Part 1 we study the spherical functions on compact symmetric pairs of arbitrary rank under a suitable multiplicity freeness assumption and additional conditions on the branching rules. The spherical functions are ...