Browsing 2020 by Title
Now showing items 8-22 of 22
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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 ℓ-torsion conjecture for ℓ-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[OWP-2020-16] (Mathematisches Forschungsinstitut Oberwolfach, 2020-08-03)We present and comment on some unpublished work of Adolf Hurwitz on quaternion arithmetic from his diaries.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⊆F and an octonion E-algebra R inside A, the set S of polynomials f(x)∈A[x] satisfying f(R)⊆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)∈Fq(x) for which the value set Vh={h(α)|α∈Fq∪{∞}} 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 L2(Ω), 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 P3
[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 P3. This configuration has appeared in various guises, perhaps post notably as ...