Browsing 1  Oberwolfach Preprints (OWP) by Title
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Fibonaccilike unimodal inverse limit spaces
[OWP201003] (Mathematisches Forschungsinstitut Oberwolfach, 2010039)We study the structure of inverse limit space of socalled Fibonaccilike tent maps. The combinatorial constraints implied by the Fibonaccilike assumption allows us to introduce certain chains that enable a more detailed ... 
Finitary Proof Systems for Kozen's μ
[OWP201626] (Mathematisches Forschungsinstitut Oberwolfach, 20161230)We present three finitary cutfree sequent calculi for the modal $μ$calculus. Two of these derive annotated sequents in the style of Stirling’s ‘tableau proof system with names’ (2014) and feature special inferences that ... 
The First Hochschild Cohomology as a Lie Algebra
[OWP201909] (Mathematisches Forschungsinstitut Oberwolfach, 20190416)In this paper we study sufficient conditions for the solvability of the first Hochschild cohomology of a finite dimensional algebra as a Lie algebra in terms of its Extquiver in arbitrary characteristic. In particular, ... 
FlagAccurate Arrangements
[OWP202301] (Mathematisches Forschungsinstitut Oberwolfach, 20230213)In [MR21], the first two authors introduced the notion of an accurate arrangement, a particular notion of freeness. In this paper, we consider a special subclass, where the property of accuracy stems from a flag of flats ... 
Formal adjoints of linear DAE operators and their role in optimal control
[OWP201115] (Mathematisches Forschungsinstitut Oberwolfach, 20110516)For regular strangenessfree linear differentialalgebraic equations (DAEs) the definition of an adjoint DAE is straightforward. This definition can be formally extended to general linear DAEs. In this paper, we analyze ... 
Formal punctured ribbons and twodimensional local fields
[OWP200801] (Mathematisches Forschungsinstitut Oberwolfach, 20080305)We investigate formal ribbons on curves. Roughly speaking, formal ribbon is a family of locally linearly compact vector spaces on a curve. We establish a onetoone correspondence between formal ribbons on curves plus some ... 
The Fourier Transform on Harmonic Manifolds of Purely Exponential Volume Growth
[OWP201912] (Mathematisches Forschungsinstitut Oberwolfach, 20190508)Let $X$ be a complete, simply connected harmonic manifold of purely exponential volume growth. This class contains all nonflat harmonic manifolds of nonpositive curvature and, in particular all known examples of harmonic ... 
FourierMukai transform on Weierstrass cubics and commuting differential operators
[OWP201603] (Mathematisches Forschungsinstitut Oberwolfach, 20160510)In this article, we describe the spectral sheaves of algebras of commuting differential operators of genus one and rank two with singular spectral curve, solving a problem posed by Previato and Wilson. We also classify all ... 
Freeness of MultiReflection Arrangements via Primitive Vector Fields
[OWP201710] (Mathematisches Forschungsinstitut Oberwolfach, 20170420)In 2002, Terao showed that every reflection multiarrangement of a real reflection group with constant multiplicity is free by providing a basis of the module of derivations. We first generalize Terao's result to ... 
A Function Algebra Providing New Mergelyan Type Theorems in Several Complex Variables
[OWP201902] (Mathematisches Forschungsinstitut Oberwolfach, 20190211)For compact sets $K\subset \mathbb C^{d}$, we introduce a subalgebra $A_{D}(K)$ of $A(K)$, which allows us to obtain Mergelyan type theorems for products of planar compact sets as well as for graphs of functions. 
Fundamental Theorem of Projective Geometry over Semirings
[OWP202109] (Mathematisches Forschungsinstitut Oberwolfach, 20211011)We state the fundamental theorem of projective geometry for semimodules over semirings, which is facilitated by recent work in the study of bases in semimodules defined over semirings. In the process we explore in detail ... 
Gcomplete reducibility in nonconnected groups
[OWP201309] (Mathematisches Forschungsinstitut Oberwolfach, 20130410)In this paper we present an algorithm for determining whether a subgroup $H$ of a nonconnected reductive group $G$ is $G$completely reducible. The algorithm consists of a series of reductions; at each step, we perform ... 
GAP Functionality for Zariski Dense Groups
[OWP201722] (Mathematisches Forschungsinstitut Oberwolfach, 20170914)In this document we describe the functionality of GAP [4] routines for Zariski dense or arithmetic groups that are developed in [1, 2, 3]. The research underlying the software was supported through the programme "Research ... 
A Generalization of the Discrete Version of Minkowski’s Fundamental Theorem
[OWP201417] (Mathematisches Forschungsinstitut Oberwolfach, 2014)One of the most fruitful results from Minkowski’s geometric viewpoint on number theory is his so called 1st Fundamental Theorem. It provides an optimal upper bound for the volume of an osymmetric convex body whose only ... 
Generalized Entropy Method for the Renewal Equation with Measure Data
[OWP201607] (Mathematisches Forschungsinstitut Oberwolfach, 20160617)We study the longtime asymptotics for the socalled McKendrickVon Foerster or renewal equation, a simple model frequently considered in structured population dynamics. In contrast to previous works, we can admit a bounded ... 
Generalized Killing spinors and Lagrangian graphs
[OWP201411] (Mathematisches Forschungsinstitut Oberwolfach, 20140820)We study generalized Killing spinors on the standard sphere $\mathbb{S}^3$, which turn out to be related to Lagrangian embeddings in the nearly Kähler manifold $S^3 \times S^3$ and to great circle flows on $\mathbb{S}^3$. ... 
Generalized Vector Cross Products and Killing Forms on Negatively Curved Manifolds
[OWP201817] (Mathematisches Forschungsinstitut Oberwolfach, 20180717)Motivated by the study of Killing forms on compact Riemannian manifolds of negative sectional curvature, we introduce the notion of generalized vector cross products on $\mathbb{R}^n$ and give their classification. Using ... 
Generating Finite Coxeter Groups with Elements of the Same Order
[OWP202007] (Mathematisches Forschungsinstitut Oberwolfach, 20200316)Supposing $G$ is a group and $k$ a natural number, $d_k(G)$ is defined to be the minimal number of elements of $G$ of order $k$ which generate $G$ (setting $d_k(G) = 0$ if $G$ has no such generating sets). This paper ... 
Geometric flows and 3manifolds : Oberwolfach Lecture 2005
[OWP200701] (Mathematisches Forschungsinstitut Oberwolfach, 2007)The current article arose from a lecture1 given by the author in October 2005 on the work of R. Hamilton and G. Perelman on Ricciflow and explains central analytical ingredients in geometric parabolic evolution equations ... 
Geometric quantization of integrable systems with hyperbolic singularities
[OWP200901] (Mathematisches Forschungsinstitut Oberwolfach, 2009)We construct the geometric quantization of a compact surface using a singular real polarization coming from an integrable system. Such a polarization always has singularities, which we assume to be of nondegenerate type. ...