Browsing by MFO Scientific Program "Research in Pairs 2019"
Now showing items 115 of 15

Chirality of Real NonSingular Cubic Fourfolds and Their Pure Deformation Classification
[OWP201914] (Mathematisches Forschungsinstitut Oberwolfach, 20190515)In our previous works we have classified real nonsingular cubic hypersurfaces in the 5dimensional projective space up to equivalence that includes both real projective transformations and continuous variations of ... 
Congruences Associated with Families of Nilpotent Subgroups and a Theorem of Hirsch
[OWP201916] (Mathematisches Forschungsinstitut Oberwolfach, 20190527)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 ... 
Group Algebras of Compact Groups. A New Way of Producing Group Hopf Algebras over Real and Complex Fields: Weakly Complete Topological Vector Spaces
[OWP201906] (Mathematisches Forschungsinstitut Oberwolfach, 20190227)Weakly complete real or complex associative algebras $A$ are necessarily projective limits of finite dimensional algebras. Their group of units $A^{1}$ is a proLie group with the associated topological Lie algebra $A_{\rm ... 
lTorsion Bounds for the Class Group of Number Fields with an l Group as Galois Group
[OWP202011] (Mathematisches Forschungsinstitut Oberwolfach, 20200504)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 ... 
Matchings and Squarefree Powers of Edge Ideals
[OWP201925] (Mathematisches Forschungsinstitut Oberwolfach, 20191111)Squarefree powers of edge ideals are intimately related to matchings of the underlying graph. In this paper we give bounds for the regularity of squarefree powers of edge ideals, and we consider the question of when such ... 
Maximal Quaternion Orders in Quadratic Extensions  in Hurwitz’s Diaries
[OWP202016] (Mathematisches Forschungsinstitut Oberwolfach, 20200803)We present and comment on some unpublished work of Adolf Hurwitz on quaternion arithmetic from his diaries. 
Minimal Codimension One Foliation of a Symmetric Space by DamekRicci Spaces
[OWP201911] (Mathematisches Forschungsinstitut Oberwolfach, 20190507)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 $A$ ... 
Multivariate Hybrid Orthogonal Functions
[OWP202004] (Mathematisches Forschungsinstitut Oberwolfach, 20200312)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 ... 
Nonexistence of Subcritical Solitary Waves
[OWP202006] (Mathematisches Forschungsinstitut Oberwolfach, 20200315)We prove the nonexistence of twodimensional 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 ... 
On Residuals of Finite Groups
[OWP201917] (Mathematisches Forschungsinstitut Oberwolfach, 20190528)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 ... 
A Quantitative Analysis of the “LionMan” Game
[OWP201918] (Mathematisches Forschungsinstitut Oberwolfach, 20190708)In this paper we analyze, based on an interplay between ideas and techniques from logic and geometric analysis, a pursuitevasion game. More precisely, we focus on a discrete lion and man game with an $\varepsilon$capture ... 
Rational Functions with Small Value Set
[OWP202005] (Mathematisches Forschungsinstitut Oberwolfach, 20200314)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
[OWP202008] (Mathematisches Forschungsinstitut Oberwolfach, 20200317)We study singularities and bifurcations of constant negative curvature surfaces in Euclidean 3space via their association with Lorentzian harmonic maps. This preprint presents the basic results on this, the full proofs ... 
SpaceTime Euler Discretization Schemes for the Stochastic 2D NavierStokes Equations
[OWP202012] (Mathematisches Forschungsinstitut Oberwolfach, 20200506)We prove that the implicit time Euler scheme coupled with finite elements space discretization for the 2D NavierStokes equations on the torus subject to a random perturbation converges in $L^2(\Omega)$, and describe the ... 
Splitting Necklaces, with Constraints
[OWP202003] (Mathematisches Forschungsinstitut Oberwolfach, 20200211)We prove several versions of Alon's "necklacesplitting theorem", subject to additional constraints, as illustrated by the following results. (1) The "almost equicardinal necklacesplitting theorem" claims that, without ...