Recent Submissions

  • On Residuals of Finite Groups 

    [OWP-2019-17] Aivazidis, Stefanos; Müller, Thomas (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-28)
    A theorem of Dolfi, Herzog, Kaplan, and Lev [DHKL07, Thm. C] asserts that in a finite group with trivial Fitting subgroup, the size of the soluble residual of the group is bounded from below by a certain power of the group ...
  • Congruences Associated with Families of Nilpotent Subgroups and a Theorem of Hirsch 

    [OWP-2019-16] Aivazidis, Stefanos; Müller, Thomas (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-27)
    Our main result associates a family of congruences with each suitable system of nilpotent subgroups of a finite group. Using this result, we complete and correct the proof of a theorem of Hirsch concerning the class number ...
  • 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 ...
  • 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 ...
  • 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 Fourier Transform on Harmonic Manifolds of Purely Exponential Volume Growth 

    [OWP-2019-12] Biswas, Kingshook; Knieper, Gerhard; Peyerimhoff, Norbert (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-08)
    Let $X$ be a complete, simply connected harmonic manifold of purely exponential volume growth. This class contains all non-flat harmonic manifolds of non-positive curvature and, in particular all known examples of harmonic ...
  • Minimal Codimension One Foliation of a Symmetric Space by Damek-Ricci Spaces 

    [OWP-2019-11] Knieper, Gerhard; Parker, John R.; Peyerimhoff, Norbert (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-07)
    In this article we consider solvable hypersurfaces of the form $N \exp(\mathbb{R} H)$ with induced metrics in the symmetric space $M = SL(3,\mathbb{C})/SU(3)$, where $H$ a suitable unit length vector in the subgroup $A$ ...
  • On the Lie Algebra Structure of $HH^1(A)$ of a Finite-Dimensional Algebra A 

    [OWP-2019-10] Linckelmann, Markus; Rubio y Degrassi, Lleonard (Mathematisches Forschungsinstitut Oberwolfach, 2019-04-17)
    Let $A$ be a split finite-dimensional associative unital algebra over a field. The first main result of this note shows that if the Ext-quiver of $A$ is a simple directed graph, then $HH^1(A)$ is a solvable Lie algebra. ...
  • 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, ...
  • On a Group Functor Describing Invariants of Algebraic Surfaces 

    [OWP-2019-08] Dietrich, Heiko; Moravec, Primož (Mathematisches Forschungsinstitut Oberwolfach, 2019-03-01)
    Liedtke (2008) has introduced group functors $K$ and $\tilde K$, which are used in the context of describing certain invariants for complex algebraic surfaces. He proved that these functors are connected to the theory of ...
  • Weighted Surface Algebras: General Version 

    [OWP-2019-07] Erdmann, Karin; Skowroński, Andrzej (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-28)
    We introduce general weighted surface algebras of triangulated surfaces with arbitrarily oriented triangles and describe their basic properties. In particular, we prove that all these algebras, except the singular disc, ...
  • Group Algebras of Compact Groups. A New Way of Producing Group Hopf Algebras over Real and Complex Fields: Weakly Complete Topological Vector Spaces 

    [OWP-2019-06] Hofmann, Karl Heinrich; Kramer, Linus (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-27)
    Weakly complete real or complex associative algebras $A$ are necessarily projective limits of finite dimensional algebras. Their group of units $A^{-1}$ is a pro-Lie group with the associated topological Lie algebra $A_{\rm ...
  • Hölder Continuity of the Spectra for Aperiodic Hamiltonians 

    [OWP-2019-05] Beckus, Siegfried; Bellissard, Jean; Cornean, Horia (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-26)
    We study the spectral location of a strongly pattern equivariant Hamiltonians arising through configurations on a colored lattice. Roughly speaking, two configurations are "close to each other" if, up to a translation, ...
  • Applications of BV Type Spaces 

    [OWP-2019-04] Appell, Jürgen; Bugajewska, Daria; Kasprzak, Piotr; Merentes, Nelson; Reinwand, Simon; Sánchez, José Luis (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-13)
  • Time Discretization Schemes for Hyperbolic Systems on Networks by ε-Expansion 

    [OWP-2019-03] Altmann, Robert; Zimmer, Christoph (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-12)
    We consider partial differential equations on networks with a small parameter $\epsilon$, which are hyperbolic for $\epsilon>0$ and parabolic for $\epsilon=0$. With a combination of an $\epsilon$-expansion and Runge-Kutta ...
  • A Function Algebra Providing New Mergelyan Type Theorems in Several Complex Variables 

    [OWP-2019-02] Falcó, Javier; Gauthier, Paul Montpetit; Manolaki, Myrto; Nestoridis, Vassili (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-11)
    For compact sets $K\subset \mathbb C^{d}$, we introduce a subalgebra $A_{D}(K)$ of $A(K)$, which allows us to obtain Mergelyan type theorems for products of planar compact sets as well as for graphs of functions.
  • 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. ...