• Ghost Algebras of Double Burnside Algebras via Schur Functors 

      [OWP-2012-09] Boltje, Robert; Danz, Susanne (Mathematisches Forschungsinstitut Oberwolfach, 2012-07-03)
      For a finite group $G$, we introduce a multiplication on the $\mathbb{Q}$-vector space with basis $\mathscr{S}_{G\times G}$, the set of subgroups of ${G \times G}$. The resulting $\mathbb{Q}$-algebra $\tilde{A}$ can be ...
    • Gibbs measures associated to the integrals of motion of the periodic derivative nonlinear Schrödinger equation 

      [OWP-2015-04] Genovese, Giuseppe; Lucatti, Renato; Valeri, Daniele (Mathematisches Forschungsinstitut Oberwolfach, 2015-05-18)
      We study the one dimensional periodic derivative nonlinear Schrödinger (DNLS) equation. This is known to be a completely integrable system, in the sense that there is an infinite sequence of formal integrals of motion $\int ...
    • Global Solutions to Stochastic Wave Equations with Superlinear Coefficients 

      [OWP-2019-26] Millet, Annie; Sanz-Solé, Marta (Mathematisches Forschungsinstitut Oberwolfach, 2019-11-13)
      We prove existence and uniqueness of a random field solution $(u(t,x);(t,x)\in [0,T]\times \mathbb{R}^d)$ to a stochastic wave equation in dimensions $d=1,2,3$ with diffusion and drift coefficients of the form $|x| ...
    • Global Variants of Hartogs' Theorem 

      [OWP-2018-24] Bochnak, Jacek; Kucharz, Wojciech (Mathematisches Forschungsinstitut Oberwolfach, 2018-11-06)
      Hartogs' theorem asserts that a separately holomorphic function, defined on an open subset of $\mathbb{C}^n$, is holomorphic in all the variables. We prove a global variant of this theorem for functions defined on an open ...
    • Gradient Canyons, Concentration of Curvature, and Lipschitz Invariants 

      [OWP-2017-35] Paunescu, Laurentiu; Tibăr, Mihai-Marius (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-13)
      We find new bi-Lipschitz invariants of holomorphic functions of two variables by using the gradient canyons and by combining analytic and geometric viewpoints on the concentration of curvature.
    • Graphical constructions for the sl(3), C2 and G2 invariants for virtual knots, virtual braids and free knots 

      [OWP-2015-13] Kauffman, Louis H.; Manturov, Vassily Olegovich (Mathematisches Forschungsinstitut Oberwolfach, 2015-07-31)
      We construct graph-valued analogues of the Kuperberg sl(3) and $G_2$ invariants for virtual knots. The restriction of the sl(3) and $G_2$ invariants for classical knots coincides with the usual Homflypt sl(3) invariant and ...
    • A graphical interface for the Gromov-Witten theory of curves 

      [OWP-2016-06] Cavalieri, Renzo; Johnson, Paul; Markwig, Hannah; Ranganathan, Dhruv (Mathematisches Forschungsinstitut Oberwolfach, 2016-05-10)
      We explore the explicit relationship between the descendant Gromov–Witten theory of target curves, operators on Fock spaces, and tropical curve counting. We prove a classical/tropical correspondence theorem for descendant ...
    • Grassmannian connection between three- and four-qubit observables, mermin's contextualities and black holes 

      [OWP-2013-17] Lévay, Péter; Planat, Michel; Saniga, Metod (Mathematisches Forschungsinstitut Oberwolfach, 2013-07-23)
      We invoke some ideas from finite geometry to map bijectively 135 heptads of mutually commuting three-qubit observables into 135 symmetric four-qubit ones. After labeling the elements of the former set in terms of a ...
    • 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 ...
    • Group-Graded Rings Satisfying the Strong Rank Condition 

      [OWP-2019-22] Kropholler, Peter H.; Lorensen, Karl (Mathematisches Forschungsinstitut Oberwolfach, 2019-08-16)
      A ring $R$ satisfies the $\textit{strong rank condition}$ (SRC) if, for every natural number $n$, the free $R$-submodules of $R^n$ all have rank $\leq n$. Let $G$ be a group and $R$ a ring strongly graded by $G$ such that ...
    • Groups with Spanier-Whitehead Duality 

      [OWP-2019-23] Nishikawa, Shintaro; Proietti, Valerio (Mathematisches Forschungsinstitut Oberwolfach, 2019-09-17)
      We introduce the notion of Spanier-Whitehead $K$-duality for a discrete group $G$, defined as duality in the KK-category between two $C*$-algebras which are naturally attached to the group, namely the reduced group ...
    • Hecke duality relations of Jacobi forms 

      [OWP-2008-03] Bringmann, Kathrin; Heim, Bernhard (Mathematisches Forschungsinstitut Oberwolfach, 2008-03-07)
      In this paper we introduce a new subspace of Jacobi forms of higher degree via certain relations among Fourier coefficients. We prove that this space can also be characterized by duality properties of certain distinguished ...
    • Heisenberg-Weyl algebra revisited: combinatorics of words and paths 

      [OWP-2009-02] Blasiak, Pawel; Duchamp, Gérard H. E.; Horzela, Andrzej; Penson, Karol A.; Solomon, Allan I. (Mathematisches Forschungsinstitut Oberwolfach, 2009)
      The Heisenberg–Weyl algebra, which underlies virtually all physical representations of Quantum Theory, is considered from the combinatorial point of view. We provide a concrete model of the algebra in terms of paths on a ...
    • Herbrand’s Theorem as Higher Order Recursion 

      [OWP-2018-01] Afshari, Bahareh; Hetzl, Stefan; Leigh, Graham E. (Mathematisches Forschungsinstitut Oberwolfach, 2018-02-19)
      We provide a means to compute Herbrand disjunctions directly from sequent calculus proofs with cuts. Our approach associates to a first-order classical proof $\pi \vdash \exists v F$, where $F$ is quantifier free, an ...
    • Higher Finiteness Properties of Reductive Arithmetic Groups in Positive Characteristic: the Rank Theorem 

      [OWP-2011-05] Bux, Kai-Uwe; Köhl, Ralf; Witzel, Stefan (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-8)
      We show that the finiteness length of an $S$-arithmetic subgroup $\Gamma$ in a noncommutative isotropic absolutely almost simple group $\mathcal{G}$ over a global function field is one less than the sum of the local ranks ...
    • Hight functions on quaternionic Stiefel manifolds 

      [OWP-2015-10] Macías-Virgós, Enrique; Strom, Jeffrey; Tanré, Daniel; Oprea, John (Mathematisches Forschungsinstitut Oberwolfach, 2015-07-29)
      In this note, we study height functions on quaternionic Stiefel manifolds and prove that all these height functions are Morse-Bott. Among them, we characterize the Morse functions and give a lower bound for their number ...
    • Holomorphic automorphic forms and cohomology 

      [OWP-2014-07] Bruggeman, Roelof W.; Ch'oe, Yŏng-ju; Diamantis, Nikolaos (Mathematisches Forschungsinstitut Oberwolfach, 2014-04-25)
      We investigate the correspondence between holomorphic automorphic forms on the upper half-plane with complex weight and parabolic cocycles. For integral weights at least 2 this correspondence is given by the Eichler integral. ...
    • Holonomy Groups of $G_2^*$-Manifolds 

      [OWP-2017-07] Fino, Anna; Kath, Ines (Mathematisches Forschungsinstitut Oberwolfach, 2017-03-07)
      We classify the holonomy algebras of manifolds admitting an indecomposable torsion free $G_2^*$-structure, i.e. for which the holonomy representation does not leave invariant any proper non-degenerate subspace. We realize ...
    • Homogenization of a nonlinear monotone problem with nonlinear Signorini boundary conditions in a domain with highly rough boundary 

      [OWP-2018-06] Gaudiello, Antonio; Mel'nyk, Taras A. (Mathematisches Forschungsinstitut Oberwolfach, 2018-04-16)
      We consider a domain $\Omega_\varepsilon\subset\mathbb{R}^N$, $N\geq2$, with a very rough boundary depending on~$\varepsilon$. For instance, if $N=3$ the domain $\Omega_\varepsilon$ has the form of a brush with an ...
    • Homological properties of piecewise hereditary algebras 

      [OWP-2009-11] Happel, Dieter; Zacharia, Dan (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-05)
      Let $\Lambda$ be a finite dimensional algebra over an algebraically closed field $k$. We will investigate homological properties of piecewise hereditary algebras $\Lambda$. In particular we give lower and upper bounds of ...