• Edifices: Building-like Spaces Associated to Linear Algebraic Groups; In memory of Jacques Tits 

      [OWP-2023-04] Bate, Michael; Martin, Benjamin; Röhrle, Gerhard (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] Grinberg, Darij (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] Boyd, Rachael; Bregman, Corey (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] Čečkin, Grigorij A.; Mel'nyk, Taras A. (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] Badea, Catalin; Grivaux, Sophie; Müller, Valdimir (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] Petersen, Kathleen L.; Sinclair, Christopher D. (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] Thuong, Lê Quy; Nguyen, Hong Duc (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] Vishnyakova, E. G. (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] Györfi, László; Döring, Maik; Walk, Harro (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] Geiges, Hansjörg; Onaran, Sinem (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] Detinko, Alla; Flannery, Dane; Hulpke, Alexander (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] Detinko, Alla; Flannery, Dane; Hulpke, Alexander (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] Boldt, Sebastian; Lauret, Emilio A. (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] Roncal, Luz; Thangavelu, Sundaram (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] Khimshiashvili, Giorgi; Panina, Gaiane; Siersma, Dirk; Zhukova, Alena (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-22)
    • Fibonacci-like unimodal inverse limit spaces 

      [OWP-2010-03] Bruin, H.; Štimac, S. (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] Afshari, Bahareh; Leigh, Graham E. (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] Rubio y Degrassi, Lleonard; Schroll, Sibylle; Solotar, Andrea (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] Mücksch, Paul; Röhrle, Gerhard; Tran, Tan Nhat (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] Kunkel, Peter; Mehrmann, Volker (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 ...