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The BerryKeating Operator on a Lattice
[OWP201623] (Mathematisches Forschungsinstitut Oberwolfach, 20161117)We construct and study a version of the BerryKeating operator with a builtin truncation of the phase space, which we choose to be a twodimensional torus. The operator is a Weyl quantisation of the classical Hamiltonian ... 
Billiards and flat surfaces
[SNAP2015001EN] (Mathematisches Forschungsinstitut Oberwolfach, 2015)[also available in German] Billiards, the study of a ball bouncing around on a table, is a rich area of current mathematical research. We discuss questions and results on billiards, and on the related topic of flat surfaces. 
Boundary Representations of Operator Spaces, and Compact Rectangular Matrix Convex Sets
[OWP201624] (Mathematisches Forschungsinstitut Oberwolfach, 20161213)We initiate the study of matrix convexity for operator spaces. We define the notion of compact rectangular matrix convex set, and prove the natural analogs of the KreinMilman and the bipolar theorems in this context. We ... 
Braid equivalences and the Lmoves
[OWP201120] (Mathematisches Forschungsinstitut Oberwolfach, 20110519)In this survey paper we present the Lmoves between braids and how they can adapt and serve for establishing and proving braid equivalence theorems for various diagrammatic settings, such as for classical knots, for knots ... 
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, ... 
Calculating conjugacy classes in Sylow psubgroups of finite Chevalley groups of rank six and seven
[OWP201310] (Mathematisches Forschungsinstitut Oberwolfach, 20130410)Let $G(q)$ be a finite Chevalley group, where $q$ is a power of a good prime $p$, and let $U(q)$ be a Sylow $p$subgroup of $G(q)$. Then a generalized version of a conjecture of Higman asserts that the number $k(U(q))$ of ... 
Categoric Aspects of Authentication
[OWP201205] (Mathematisches Forschungsinstitut Oberwolfach, 20120424) 
Categorical Linearly Ordered Structures
[OWP201808] (Mathematisches Forschungsinstitut Oberwolfach, 20180426)We prove that for every computable limit ordinal $\alpha$ there exists a computable linear ordering $\mathcal{A}$ which is $\Delta^0_\alpha$categorical and $\alpha$ is smallest such, but nonetheless for every isomorphic ... 
A categorical model for the virtual braid group
[OWP201119] (Mathematisches Forschungsinstitut Oberwolfach, 20110518) 
Central Limit Theorems for the Radial Spanning Tree
[OWP201418] (Mathematisches Forschungsinstitut Oberwolfach, 2014)Consider a homogeneous Poisson point process in a compact convex set in ddimensional Euclidean space which has interior points and contains the origin. The radial spanning tree is constructed by connecting each point of ... 
Chaos and chaotic fluid mixing
[SNAP2015005EN] (Mathematisches Forschungsinstitut Oberwolfach, 2015)Very simple mathematical equations can give rise to surprisingly complicated, chaotic dynamics, with behavior that is sensitive to small deviations in the initial conditions. We illustrate this with a single recurrence ... 
A Characterization of Semisimple Plane Polynomial Automorphisms
[OWP200808] (Mathematisches Forschungsinstitut Oberwolfach, 20080312)It is wellknown that an element of the linear group $GL_n(\mathbb{C})$ is semisimple if and only if its conjugacy class is Zariski closed. The aim of this paper is to show that the same result holds for the group of complex ... 
Classical nonintegrability, quantum chaos
[OWS27] (Birkhäuser Basel, 1997)Our DMV Seminar on 'Classical Nonintegrability, Quantum Chaos' intended to introduce students and beginning researchers to the techniques applied in nonin tegrable classical and quantum dynamics. Several of these lectures ... 
Classification of Higher Dimension Algebraic Varieties
[OWS41] (Birkhäuser Basel, 2010)This book focuses on recent advances in the classification of complex projective varieties. It is divided into two parts. The first part gives a detailed account of recent results in the minimal model program. In particular, ... 
Classification of idempotent states on the compact quantum groups Uq(2), SUq(2) and SOq(3)
[OWP200908] (Mathematisches Forschungsinstitut Oberwolfach, 20090302)We give a simple characterisation of those idempotent states on compact quantum groups which arise as Haar states on quantum subgroups, show that all idempotent states on quantum groups $U_q(2)$, $SU_q(2)$, and $SO_q(3) ... 
Classification of totally real elliptic Lefschetz fibrations via necklace diagrams
[OWP201113] (Mathematisches Forschungsinstitut Oberwolfach, 2011)We show that totally real elliptic Lefschetz brations that admit a real section are classified by their "real loci" which is nothing but an $S^1$valued Morse function on the real part of the total space. We assign to ... 
The Cleavage Operad and String Topology of Higher Dimension
[OWP201137] (Mathematisches Forschungsinstitut Oberwolfach, 2011) 
Closed geodesics on surfaces and Riemannian manifolds
[SNAP2017005EN] (Mathematisches Forschungsinstitut Oberwolfach, 20171207)Geodesics are special paths in surfaces and socalled Riemannian manifolds which connect close points in the shortest way. Closed geodesics are geodesics which go back to where they started. In this snapshot we talk ... 
Cluster structures on simple complex lie groups and the BelavinDrinfeld classification
[OWP201110] (Mathematisches Forschungsinstitut Oberwolfach, 20110512)We study natural cluster structures in the rings of regular functions on simple complex Lie groups and PoissonLie structutures compatible with these cluster structures. According to our main conjecture, each class in the ... 
Cocharacterclosure and spherical buildings
[OWP201512] (Mathematisches Forschungsinstitut Oberwolfach, 20150729)Let $k$ be a field, let $G$ be a reductive $k$group and $V$ an affine $k$variety on which $G$ acts. In this note we continue our study of the notion of cocharacterclosed $G(k)$orbits in $V$. In earlier work we used a ...