Browsing 2020 by Title

Now showing items 8-22 of 22

    • l-Torsion Bounds for the Class Group of Number Fields with an l -Group as Galois Group 

      [OWP-2020-11] Klüners, Jürgen; Wang, Jiuya (Mathematisches Forschungsinstitut Oberwolfach, 2020-05-04)
      We describe the relations among the $\ell$-torsion conjecture for $\ell$-extensions, the discriminant multiplicity conjecture for nilpotent extensions and a conjecture of Malle giving an upper bound for the number of ...

    • Maximal Quaternion Orders in Quadratic Extensions - in Hurwitz’s Diaries 

      [OWP-2020-16] Oswald, Nicola; Steuding, Jörn (Mathematisches Forschungsinstitut Oberwolfach, 2020-08-03)
      We present and comment on some unpublished work of Adolf Hurwitz on quaternion arithmetic from his diaries.

    • Multivariate Hybrid Orthogonal Functions 

      [OWP-2020-04] Bracciali, Cleonice F.; Pérez, Teresa E. (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-12)
      We consider multivariate orthogonal functions satisfying hybrid orthogonality conditions with respect to a moment functional. This kind of orthogonality means that the product of functions of different parity order ...

    • Nondegenerate Invariant Symmetric Bilinear Forms on Simple Lie Superalgebras in Characteristic 2 

      [OWP-2020-02] Krutov, Andrey; Lebedev, Alexei; Leites, Dimitry; Shchepochkina, Irina (Mathematisches Forschungsinstitut Oberwolfach, 2020-02-04)
      As is well-known, the dimension of the space of non-degenerate invariant symmetric bilinear forms (NISes) on any simple finite-dimensional Lie algebra or Lie superalgebra is equal to at most 1 if the characteristic of the ...

    • Nonexistence of Subcritical Solitary Waves 

      [OWP-2020-06] Kozlov, Vladimir; Lokharu, Evgeniy; Wheeler, Miles H. (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-15)
      We prove the nonexistence of two-dimensional solitary gravity water waves with subcritical wave speeds and an arbitrary distribution of vorticity. This is a longstanding open problem, and even in the irrotational case there ...

    • Octonion Polynomials with Values in a Subalgebra 

      [OWP-2020-21] Chapman, Adam (Mathematisches Forschungsinstitut Oberwolfach, 2020-10-22)
      In this paper, we prove that given an octonion algebra $A$ over a field $F$, a subring $E \subseteq F$ and an octonion $E$-algebra $R$ inside $A$, the set $S$ of polynomials $f(x) \in A[x]$ satisfying $f(R) \subseteq R$ ...

    • On Weakly Complete Universal Enveloping Algebras of pro-Lie Algebras 

      [OWP-2020-10] Hofmann, Karl Heinrich; Kramer, Linus (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-27)

    • The Pelletier-Ressayre Hidden Symmetry for Littlewood-Richardson Coefficients 

      [OWP-2020-18] Grinberg, Darij (Mathematisches Forschungsinstitut Oberwolfach, 2020-09-08)
      We prove an identity for Littlewood–Richardson coefficients conjectured by Pelletier and Ressayre. The proof relies on a novel birational involution defined over any semifield.

    • Positive Line Bundles Over the Irreducible Quantum Flag Manifolds 

      [OWP-2020-01] Díaz García, Fredy; Krutov, Andrey; Ó Buachalla, Réamonn; Somberg, Petr; Strung, Karen R. (Mathematisches Forschungsinstitut Oberwolfach, 2020-02-03)
      Noncommutative Kähler structures were recently introduced by the third author as a framework for studying noncommutative Kähler geometry on quantum homogeneous spaces. It was subsequently observed that the notion of a ...

    • Rational Functions with Small Value Set 

      [OWP-2020-05] Bartoli, Daniele; Borges, Herivelto; Quoos, Luciane (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-14)
      In connection with Galois Theory and Algebraic Curves, this paper investigates rational functions $h(x) = f(x)/g(x) \in \mathbb{F}_q(x)$ for which the value set $V_h = {\{h(α) | α \in \mathbb{F}_q \cup\{\infty\}}\}$ is ...

    • Singularities and Bifurcations of Pseudospherical Surfaces 

      [OWP-2020-08] Brander, David; Tari, Farid (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-17)
      We study singularities and bifurcations of constant negative curvature surfaces in Euclidean 3-space via their association with Lorentzian harmonic maps. This preprint presents the basic results on this, the full proofs ...

    • Space-Time Euler Discretization Schemes for the Stochastic 2D Navier-Stokes Equations 

      [OWP-2020-12] Bessaih, Hakima; Millet, Annie (Mathematisches Forschungsinstitut Oberwolfach, 2020-05-06)
      We prove that the implicit time Euler scheme coupled with finite elements space discretization for the 2D Navier-Stokes equations on the torus subject to a random perturbation converges in $L^2(\Omega)$, and describe the ...

    • Splitting Necklaces, with Constraints 

      [OWP-2020-03] Jojic, Dusko; Panina, Gaiane; Zivaljevic, Rade (Mathematisches Forschungsinstitut Oberwolfach, 2020-02-11)
      We prove several versions of Alon's "necklace-splitting theorem", subject to additional constraints, as illustrated by the following results. (1) The "almost equicardinal necklace-splitting theorem" claims that, without ...

    • Theoretical Analysis and Simulation Methods for Hawkes Processes and their Diffusion Approximation 

      [OWP-2020-09] Chevallier, Julien; Melnykova, Anna; Tubikanec, Irene (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-30)
      Oscillatory systems of interacting Hawkes processes with Erlang memory kernels were introduced in Ditlevsen and Löcherbach (2017). They are piecewise deterministic Markov processes (PDMP) and can be approximated by a ...

    • Unexpected Properties of the Klein Configuration of 60 Points in $\mathbb{P}^3$ 

      [OWP-2020-19] Pokora, Piotr; Szemberg, Tomasz; Szpond, Justyna (Mathematisches Forschungsinstitut Oberwolfach, 2020-10-07)
      Felix Klein in course of his study of the regular and its symmetries encountered a highly symmetric configuration of 60 points in $\mathbb{P}^3$. This configuration has appeared in various guises, perhaps post notably as ...