• The Becker-Gottlieb Transfer: a Geometric Description 

      [OWP-2019-13] Wang, Yi-Sheng (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-14)
      In this note, we examine geometric aspects of the Becker-Gottlieb transfer in terms of the Umkehr and index maps, and rework some classic index theorems, using the cohomological formulae of the Becker-Gottlieb transfer. ...
    • The Berry-Keating Operator on a Lattice 

      [OWP-2016-23] Bolte, Jens; Egger, Sebastian; Keppeler, Stefan (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 ...
    • Birational Rowmotion on a Rectangle over a Noncommutative Ring 

      [OWP-2022-17] Grinberg, Darij; Roby, Tom (Mathematisches Forschungsinstitut Oberwolfach, 2022-09-20)
      We extend the periodicity of birational rowmotion for rectangular posets to the case when the base field is replaced by a noncommutative ring (under appropriate conditions). This resolves a conjecture from 2014. The proof ...
    • Boundary Conditions for Scalar Curvature 

      [OWP-2021-01] Bär, Christian; Hanke, Bernhard (Mathematisches Forschungsinstitut Oberwolfach, 2021-01-04)
      Based on the Atiyah-Patodi-Singer index formula, we construct an obstruction to positive scalar curvature metrics with mean convex boundaries on spin manifolds of infinite $K$-area. We also characterize the extremal case. ...
    • Boundary Representations of Operator Spaces, and Compact Rectangular Matrix Convex Sets 

      [OWP-2016-24] Fuller, Adam H.; Hartz, Michael; Lupini, Martino (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 ...
    • Bounded Weight Modules for Basic Classical Lie Superalgebras at Infinity 

      [OWP-2022-09] Grantcharov, Dimitar; Penkov, Ivan; Serganova, Vera (Mathematisches Forschungsinstitut Oberwolfach, 2022-05-30)
      We classify simple bounded weight modules over the complex simple Lie superalgebras $\mathfrak{sl}(\infty |\infty)$ and $\mathfrak{osp} (m | 2n)$, when at least one of $m$ and $n$ equals $\infty$. For $\mathfrak{osp} (m | ...
    • Braid equivalences and the L-moves 

      [OWP-2011-20] Lambropoulou, Sofia (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 ...
    • Braidoids 

      [OWP-2020-17] Gügümcü, Neslihan; Lambropoulou, Sofia (Mathematisches Forschungsinstitut Oberwolfach, 2020-09-03)
      Braidoids generalize the classical braids and form a counterpart theory to the theory of planar knotoids, just as the theory of braids does for the theory of knots. In this paper, we introduce the notion of braidoids in ...
    • Bredon Cohomology and Robot Motion Planning 

      [OWP-2017-34] Farber, Michael; Grant, Mark; Lupton, Gregory; Oprea, John (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, ...
    • The C-Map as a Functor on Certain Variations of Hodge Structure 

      [OWP-2021-04] Mantegazza, Mauro; Saha, Arpan (Mathematisches Forschungsinstitut Oberwolfach, 2021-03-15)
      We give a new manifestly natural presentation of the supergravity c-map. We achieve this by giving a more explicit description of the correspondence between projective special Kähler manifolds and variations of Hodge ...
    • Calculating conjugacy classes in Sylow p-subgroups of finite Chevalley groups of rank six and seven 

      [OWP-2013-10] Goodwin, Simon M.; Mosch, Peter; Röhrle, Gerhard (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] Stump, Christian; Thomas, Hugh; Williams, Nathan (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] Schillewaert, Jeroen; Thas, Koen (Mathematisches Forschungsinstitut Oberwolfach, 2012-04-24)
    • Categorical Linearly Ordered Structures 

      [OWP-2018-08] Downey, Rod; Melnikov, Alexander; Ng, Keng Meng (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] Kauffman, Louis H.; Lambropoulou, Sofia (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-18)
    • Central Limit Theorems for the Radial Spanning Tree 

      [OWP-2014-18] Schulte, Matthias; Thäle, Christoph (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 ...
    • A Characterization of Semisimple Plane Polynomial Automorphisms 

      [OWP-2008-08] Maubach, Stefan; Furter, Jean-Philippe (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 ...
    • Characterization of Tropical Planar Curves up to Genus Six 

      [OWP-2022-06] Tewari, Ayush Kumar (Mathematisches Forschungsinstitut Oberwolfach, 2022-03-16)
      We provide new forbidden criterion for realizability of smooth tropical plane curves. This in turn provides us a complete classification of smooth tropical plane curves up to genus six.
    • A Cheeger Type Inequality in Finite Cayley Sum Graphs 

      [OWP-2019-21] Biswas, Arindam; Saha, Jyoti Prakash (Mathematisches Forschungsinstitut Oberwolfach, 2019-07-31) - (5 May - 27 July 2019)
      Let $G$ be a finite group and $S$ be a symmetric generating set of $G$ with $|S| = d$. We show that if the undirected Cayley sum graph $C_{\Sigma}(G,S)$ is an expander graph and is non-bipartite, then the spectrum of its ...
    • Chirality of Real Non-Singular Cubic Fourfolds and Their Pure Deformation Classification 

      [OWP-2019-14] Finashin, Sergey; Kharlamov, Viatcheslav (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-15)
      In our previous works we have classified real non-singular cubic hypersurfaces in the 5-dimensional projective space up to equivalence that includes both real projective transformations and continuous variations of ...