Browsing 1 - Oberwolfach Preprints (OWP) by Title
Now showing items 93-112 of 406
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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 ... -
An Explicit Formula for the Dirac Multiplicities on Lens Spaces
[OWP-2014-19] (Mathematisches Forschungsinstitut Oberwolfach, 2014)We present a new description of the spectrum of the (spin-) Dirac operator $D$ on lens spaces. Viewing a spin lens space $L$ as a locally symmetric space $\Gamma \setminus Spin(2m)/Spin(2m-1)$ and exploiting the representation ... -
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. -
Extremal configurations of polygonal linkages
[OWP-2011-24] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-22) -
Fibonacci-like unimodal inverse limit spaces
[OWP-2010-03] (Mathematisches Forschungsinstitut Oberwolfach, 2010-03-9)We study the structure of inverse limit space of so-called Fibonacci-like tent maps. The combinatorial constraints implied by the Fibonacci-like assumption allows us to introduce certain chains that enable a more detailed ... -
Finitary Proof Systems for Kozen's μ
[OWP-2016-26] (Mathematisches Forschungsinstitut Oberwolfach, 2016-12-30)We present three finitary cut-free sequent calculi for the modal $μ$-calculus. Two of these derive annotated sequents in the style of Stirling’s ‘tableau proof system with names’ (2014) and feature special inferences that ... -
The First Hochschild Cohomology as a Lie Algebra
[OWP-2019-09] (Mathematisches Forschungsinstitut Oberwolfach, 2019-04-16)In this paper we study sufficient conditions for the solvability of the first Hochschild cohomology of a finite dimensional algebra as a Lie algebra in terms of its Ext-quiver in arbitrary characteristic. In particular, ... -
Flag-Accurate Arrangements
[OWP-2023-01] (Mathematisches Forschungsinstitut Oberwolfach, 2023-02-13)In [MR21], the first two authors introduced the notion of an accurate arrangement, a particular notion of freeness. In this paper, we consider a special subclass, where the property of accuracy stems from a flag of flats ... -
Formal adjoints of linear DAE operators and their role in optimal control
[OWP-2011-15] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-16)For regular strangeness-free linear differential-algebraic equations (DAEs) the definition of an adjoint DAE is straightforward. This definition can be formally extended to general linear DAEs. In this paper, we analyze ...