Browsing 1  Oberwolfach Preprints (OWP) by Title
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Supertropical Quadratic Forms I
[OWP201327] (Mathematisches Forschungsinstitut Oberwolfach, 2013)We initiate the theory of a quadratic form q over a semiring $R$. As customary, one can write $q(x+y)=q(x)+q(y)+b(x,y)$, where b is a companion bilinear form. But in contrast to the ringtheoretic case, the companion ... 
Supertropical semirings and supervaluations
[OWP201005] (Mathematisches Forschungsinstitut Oberwolfach, 2010)We interpret a valuation $\upsilon$ on a ring $R$ as a map $\upsilon:R \rightarrow M$ into a so called bipotent semiring $M$ (the usual maxplus setting), and then define a supervaluation $\varphi$ as a suitable map into ... 
Sur le Minimum de la Fonction de Brjuno
[OWP201826] (Mathematisches Forschungsinstitut Oberwolfach, 20181211)The Brjuno function attains a strict global minimum at the golden section. 
The Sylow Structure of Scalar Automorphism Groups
[OWP201805] (Mathematisches Forschungsinstitut Oberwolfach, 20180322)For any locally compact abelian periodic group A its automorphism group contains as a subgroup those automorphisms that leave invariant every closed subgroup of A, to be denoted by SAut(A). This subgroup is again a locally ... 
The TGraph of a Multigraded Hilbert Scheme
[OWP201134] (Mathematisches Forschungsinstitut Oberwolfach, 2011)The $T$graph of a multigraded Hilbert scheme records the zero and onedimensional orbits of the $T=(K^*)^n$ action on the Hilbert scheme induced from the $T$action on $\mathbb{A}^n$. It has vertices the $T$fixed points, ... 
Tensor Representations of q(∞)
[OWP201609] (Mathematisches Forschungsinstitut Oberwolfach, 20160617)We introduce a symmetric monoidal category of modules over the direct limit queer superalgebra $\mathfrak{q}(\infty)$. The category can be defined in two equivalent ways with the aid of the large annihilator condition. ... 
Theoretical Analysis and Simulation Methods for Hawkes Processes and their Diffusion Approximation
[OWP202009] (Mathematisches Forschungsinstitut Oberwolfach, 20200330)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 ... 
There is a unique real tight contact 3ball
[OWP201001] (Mathematisches Forschungsinstitut Oberwolfach, 2010)We prove that there is a unique real tight contact structure on the 3ball with convex boundary up to isotopy through real tight contact structures. We also give a partial classification of the real tight solid tori with ... 
Tilting on noncommutative rational projective curves
[OWP200914] (Mathematisches Forschungsinstitut Oberwolfach, 20090308)In this article we introduce a new class of noncommutative projective curves and show that in certain cases the derived category of coherent sheaves on them has a tilting complex. In particular, we prove that the right ... 
Time and band limiting for matrix valued functions, an example
[OWP201508] (Mathematisches Forschungsinstitut Oberwolfach, 20150729)The main purpose of this paper is to extend to a situation involving matrix valued orthogonal polynomials and spherical functions, a result that traces its origin and its importance to work of Claude Shannon in laying the ... 
Time Discretization Schemes for Hyperbolic Systems on Networks by εExpansion
[OWP201903] (Mathematisches Forschungsinstitut Oberwolfach, 20190212)We consider partial differential equations on networks with a small parameter $\epsilon$, which are hyperbolic for $\epsilon>0$ and parabolic for $\epsilon=0$. With a combination of an $\epsilon$expansion and RungeKutta ... 
Torsionfree Covers of Solvable Minimax Groups
[OWP201515] (Mathematisches Forschungsinstitut Oberwolfach, 20151118)We prove that every finitely generated solvable minimax group can be realized as a quotient of a torsionfree solvable minimax group. This result has an application to the investigation of random walks on finitely generated ... 
Totally Acyclic Complexes
[OWP201614] (Mathematisches Forschungsinstitut Oberwolfach, 20160817)We prove first (Proposition 3) that, over any ring $R$, an acyclic complex of projective modules is totally acyclic if and only if the cycles of every acyclic complex of Gorenstein projective modules are Gorenstein projective. ... 
The Tutte Polynomial of Ideal Arrangements
[OWP201828] (Mathematisches Forschungsinstitut Oberwolfach, 20181221)The Tutte polynomial is originally a bivariate polynomial enumerating the colorings of a graph and of its dual graph. But it reveals more of the internal structure of the graph like its number of forests, of spanning ... 
Unconditional Convergence of Spectral Decompositions of 1D Dirac Operators with Regular Boundary Conditions
[OWP201021] (Mathematisches Forschungsinstitut Oberwolfach, 20100319) 
A Uniform Model for KirillovReshetikhin Crystals I: Lifting the Parabolic Quantum Bruhat Graph
[OWP201218] (Mathematisches Forschungsinstitut Oberwolfach, 2012)We consider two lifts of the parabolic quantum Bruhat graph, one into the Bruhat order in the affine Weyl group and the other into a levelzero weight poset first considered by Littelmann. The lift into the affine Weyl ... 
Upper bounds for the number of solutions to quartic thue equations
[OWP201121] (Mathematisches Forschungsinstitut Oberwolfach, 2011)We will give upper bounds for the number of integral solutions to quartic Thue equations. Our main tool here is a logarithmic curve $\phi(x,y)$ that allows us to use the theory of linear forms in logarithms. This manuscript ... 
Upper tails for intersection local times of random walks in supercritical dimensions
[OWP200802] (Mathematisches Forschungsinstitut Oberwolfach, 20080306)We determine the precise asymptotics of the logarithmic upper tail probability of the total intersection local time of $p$ independent random walks in $\mathbb{Z}^d$ under the assumption $p(d2)>d$. Our approach allows a ... 
Urn Models & Operator Ordering Procedures
[OWP200806] (Mathematisches Forschungsinstitut Oberwolfach, 20080310)Ordering of operators is purely combinatorial task involving a number of commutators shuffling components of operator expression to desired form. Here we show how it can be illustrated by simple urn models in which normal ... 
The Varchenko Determinant of a Coxeter Arrangement
[OWP201733] (Mathematisches Forschungsinstitut Oberwolfach, 20171124)The Varchenko determinant is the determinant of a matrix defined from an arrangement of hyperplanes. Varchenko proved that this determinant has a beautiful factorization. It is, however, not possible to use this factorization ...