Browsing 1 - Oberwolfach Preprints (OWP) by Title
Now showing items 84-103 of 403
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Diophantine Approximation in Metric Space
[OWP-2021-07] (Mathematisches Forschungsinstitut Oberwolfach, 2021-06-14)Diophantine approximation is traditionally the study of how well real numbers are approximated by rationals. We propose a model for studying Diophantine approximation in an arbitrary totally bounded metric space where the ... -
Dirichlet Approximation and Universal Dirichlet
[OWP-2016-12] (Mathematisches Forschungsinstitut Oberwolfach, 2016-08-16)We characterize the uniform limits of Dirichlet polynomials on a right half plane. We extend the approximation theorems of Runge, Mergelyan and Vitushkin to the Dirichlet setting with respect to the Euclidean distance and ... -
Discrete non-commutative integrability: the proof of a conjecture by M. Kontsevich
[OWP-2009-24] (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-17)We prove a conjecture of Kontsevich regarding the solutions of rank two recursion relations for non-commutative variables which, in the commutative case, reduce to rank two cluster algebras of affine type. The conjecture ... -
Discrete Translates in Lp (R)
[OWP-2015-09] (Mathematisches Forschungsinstitut Oberwolfach, 2015-06-18)A set $\Lambda$ is called $p$-spectral if there is a function $g \in L^p (\mathbb{R})$ such that all $\Lambda$-translates $\{g(t-\lambda),\lambda \in \Lambda\}$ span $L^p(\mathbb{R})$. We prove that exponentially small ... -
Discretization of Inherent ODEs and the Geometric Integration of DAEs with Symmetries
[OWP-2022-10] (Mathematisches Forschungsinstitut Oberwolfach, 2022-06-08)Discretization methods for differential-algebraic equations (DAEs) are considered that are based on the integration of an associated inherent ordinary differential equation (ODE). This allows to make use of any discretization ... -
Dominance and Transmissions in Supertropical Valuation Theory
[OWP-2011-07] (Mathematisches Forschungsinstitut Oberwolfach, 2011)This paper is a sequel of [IKR1], where we defined supervaluations on a commutative ring $R$ and studied a dominance relation $\Phi >= v$ between supervaluations $\varphi$ and $\upsilon$ on $R$, aiming at an enrichment of ... -
Drawing large pictures at random : Oberwolfach Lecture 2007
[OWP-2007-08] (Mathematisches Forschungsinstitut Oberwolfach, 2007)This lecture is of very introductory nature. The goal will be to describe specific concrete questions, and to use them as a tool to convey some general ideas. Let me therefore skip the general introduction and immediately ... -
Dynamics of Gravitational Collapse in the Axisymmetric Einstein-Vlasov System
[OWP-2020-22] (Mathematisches Forschungsinstitut Oberwolfach, 2020-12-15)We numerically investigate the dynamcis near black hole formation of solutions to the Einstein-Vlasov system in axisymmetry. Our results are obtained using a particle-in-cell and finite difference code based on the (2+1)+1 ... -
Edifices: Building-like Spaces Associated to Linear Algebraic Groups; In memory of Jacques Tits
[OWP-2023-04] (Mathematisches Forschungsinstitut Oberwolfach, 2023-06-19)Given a semisimple linear algebraic $k$-group $G$, one has a spherical building $Δ_G$, and one can interpret the geometric realisation $Δ_G(\mathbb R)$ of $Δ_G$ in terms of cocharacters of $G$. The aim of this paper is to ... -
The Elser Nuclei Sum Revisited
[OWP-2021-05] (Mathematisches Forschungsinstitut Oberwolfach, 2021-03-16)Fix a finite undirected graph $\Gamma$ and a vertex $v$ of $\Gamma$. Let $E$ be the set of edges of $\Gamma$. We call a subset $F$ of $E$ $\textit{pandemic}$ if each edge of $\Gamma$ has at least one endpoint that can be ... -
Embedding Spaces of Split Links
[OWP-2022-13] (Mathematisches Forschungsinstitut Oberwolfach, 2022-08-01)We study the homotopy type of the space $\mathcal{E}(L)$ of unparametrised embeddings of a split link $L=L_1\sqcup \ldots \sqcup L_n$ in $\mathbb{R}^3$. Inspired by work of Brendle and Hatcher, we introduce a semi-simplicial ... -
Enhanced Spatial Skin-Effect for Free Vibrations of a Thick Cascade Junction with "Super Heavy" Concentrated Masses
[OWP-2013-26] (Mathematisches Forschungsinstitut Oberwolfach, 2013-12-13)The asymptotic behavior (as $\varepsilon \to 0$) of eigenvalues and eigenfunctions of a boundary-value problem for the Laplace operator in a thick cascade junction with concentrated masses is studied. This cascade junction ... -
Epsilon-hypercyclic operators
[OWP-2008-19] (Mathematisches Forschungsinstitut Oberwolfach, 2008-03-19)For each fixed number $\varepsilon$ in $(0, 1)$ we construct a bounded linear operator on the Banach space $\ell_1$ having a certain orbit which intersects every cone of aperture $\varepsilon$, but with every orbit avoiding ... -
Equidistribution of Elements of Norm 1 in Cyclic Extensions
[OWP-2014-13] (Mathematisches Forschungsinstitut Oberwolfach, 2014-08-20)Upon quotienting by units, the elements of norm 1 in a number field $K$ form a countable subset of a torus of dimension $r_1+r_2-1$ where $r_1$ are the numbers of real and pairs of complex embeddings. When $K$ is Galois ... -
Euler Reflexion Formulas for Motivic Multiple Zeta Functions
[OWP-2015-17] (Mathematisches Forschungsinstitut Oberwolfach, 2015-11-18)We introduce a new notion of *-product of two integrable series with coeficients in distinct Grothendieck rings of algebraic varieties, preserving the integrability and commuting with the limit of rational series. In the ... -
Even-homogeneous supermanifolds on the complex projective line
[OWP-2013-02] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)The classification of even-homogeneous complex supermanifolds of dimension $1|m$, $m<=3$, on $\mathbb{CP}^1$ up to isomorphism is given. An explicit description of such supermanifolds in terms of local charts and coordinates ... -
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 ... -
Exceptional Legendrian Torus Knots
[OWP-2018-04] (Mathematisches Forschungsinstitut Oberwolfach, 2018-03-21)We present classification results for exceptional Legendrian realisations of torus knots. These are the first results of that kind for non-trivial topological knot types. Enumeration results of Ding-Li-Zhang concerning ... -
Experimenting with Symplectic Hypergeometric Monodromy Groups
[OWP-2019-15] (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-22)We present new computational results for symplectic monodromy groups of hypergeometric differential equations. In particular, we compute the arithmetic closure of each group, sometimes justifying arithmeticity. The results ... -
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 ...