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] (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] (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We present and comment on some unpublished work of Adolf Hurwitz on quaternion arithmetic from his diaries.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] (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] (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] (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] (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] (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-27)
• The Pelletier-Ressayre Hidden Symmetry for Littlewood-Richardson Coefficients ﻿

[OWP-2020-18] (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] (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] (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] (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] (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] (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] (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] (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 ...