Now showing items 21-40 of 437

• #### Aperiodic Order and Spectral Properties ﻿

[SNAP-2017-003-EN] (Mathematisches Forschungsinstitut Oberwolfach, 2017-09-14)
Periodic structures like a typical tiled kitchen floor or the arrangement of carbon atoms in a diamond crystal certainly possess a high degree of order. But what is order without periodicity? In this snapshot, we are ...
• #### Applications of BV Type Spaces ﻿

[OWP-2019-04] (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-13)
• #### Approximation of discrete functions and size of spectrum ﻿

[OWP-2009-17] (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-11)
Let $\Lambda \subset \mathbb{R}$ be a uniformly discrete sequence and $S \subset \mathbb{R}$ a compact set. We prove that if there exists a bounded sequence of functions in Paley-Wiener space $PW_s$, which approximates ...
• #### Arrangements of lines ﻿

[SNAP-2014-005-EN] (Mathematisches Forschungsinstitut Oberwolfach, 2014)
We discuss certain open problems in the context of arrangements of lines in the plane.
• #### Asymptotic behavior of the eigenvalues and eigenfunctions to a spectral problem in thick cascade junction with concentrated masses ﻿

[OWP-2011-12] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-14)
The asymptotic behavior (as $\varepsilon \to 0$) of eigenvalues and eigenfunctions of a boundaryvalue problem for the Laplace operator in a thick cascade junction with concentrated masses is investigated. This cascade ...
• #### Asymptotic statistics ﻿

(Birkhäuser Basel, 1990)
• #### Averages of Shifted Convolutions of d3(n) ﻿

[OWP-2011-11] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-13)
We investigate the first and second moments of shifted convolutions of the generalised divisor function $d_3(n)$.
• #### The Berry-Keating Operator on a Lattice ﻿

[OWP-2016-23] (Mathematisches Forschungsinstitut Oberwolfach, 2016-11-17)
We construct and study a version of the Berry-Keating operator with a built-in truncation of the phase space, which we choose to be a two-dimensional torus. The operator is a Weyl quantisation of the classical Hamiltonian ...
• #### Billiards and flat surfaces ﻿

[SNAP-2015-001-EN] (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 ﻿

[OWP-2016-24] (Mathematisches Forschungsinstitut Oberwolfach, 2016-12-13)
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 Krein-Milman and the bipolar theorems in this context. We ...
• #### Braid equivalences and the L-moves ﻿

[OWP-2011-20] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-19)
In this survey paper we present the L-moves 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 ﻿

[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, ...
• #### Calculating conjugacy classes in Sylow p-subgroups of finite Chevalley groups of rank six and seven ﻿

[OWP-2013-10] (Mathematisches Forschungsinstitut Oberwolfach, 2013-04-10)
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 ...
• #### Cataland: Why the Fuß? ﻿

[OWP-2019-01] (Mathematisches Forschungsinstitut Oberwolfach, 2019-01-21)
The three main objects in noncrossing Catalan combinatorics associated to a finite Coxeter system are noncrossing partitions, clusters, and sortable elements. The first two of these have known Fuß-Catalan generalizations. ...
• #### Categoric Aspects of Authentication ﻿

[OWP-2012-05] (Mathematisches Forschungsinstitut Oberwolfach, 2012-04-24)
• #### Categorical Linearly Ordered Structures ﻿

[OWP-2018-08] (Mathematisches Forschungsinstitut Oberwolfach, 2018-04-26)
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 ﻿

[OWP-2011-19] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-18)
• #### Central Limit Theorems for the Radial Spanning Tree ﻿

[OWP-2014-18] (Mathematisches Forschungsinstitut Oberwolfach, 2014)
Consider a homogeneous Poisson point process in a compact convex set in d-dimensional 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 ﻿

[SNAP-2015-005-EN] (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 ﻿

[OWP-2008-08] (Mathematisches Forschungsinstitut Oberwolfach, 2008-03-12)
It is well-known 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 ...