Browsing 1 - Oberwolfach Preprints (OWP) by Title
Now showing items 86-105 of 413
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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 ... -
Diameter and Connectivity of Finite Simple Graphs II
[OWP-2024-09] (Mathematisches Forschungsinstitut Oberwolfach, 2024-09-05)Let $G$ be a finite simple non-complete connected graph on $[n] = \{1, \ldots, n\}$ and $\kappa(G) \geq 1$ its vertex connectivity. Let $f(G)$ denote the number of free vertices of $G$ and $\mathrm{diam}(G)$ the diameter ... -
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 ... -
Domain-Scaled Regular Variation: Mathematical Foundations for a New Tail Process
[OWP-2025-02] (Mathematisches Forschungsinstitut Oberwolfach, 2025-02)Threshold exceedances of stochastic processes in space and time often appear to be more localized the more extreme they are. While classical regularly varying stochastic processes cannot model this effect, we introduce an ... -
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 ...