Browsing 1 - Oberwolfach Preprints (OWP) by Title
Now showing items 376-392 of 392
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The Varchenko Determinant of a Coxeter Arrangement
[OWP-2017-33] (Mathematisches Forschungsinstitut Oberwolfach, 2017-11-24)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 ... -
Varieties of Invariant Subspaces Given by Littlewood-Richardson Tableaux
[OWP-2014-01] (Mathematisches Forschungsinstitut Oberwolfach, 2014-04-25)Given partitions $\alpha, \beta, \gamma$, the short exact sequences $0 \rightarrow N_\alpha \rightarrow N_\beta \rightarrow N_\gamma \rightarrow 0$ of nilpotent linear operators of Jordan types $\alpha, \beta, \gamma$, ... -
Vector bundles on degenerations of elliptic curves and Yang-Baxter equations
[OWP-2007-04] (Mathematisches Forschungsinstitut Oberwolfach, 2007-03-22)In this paper we introduce the notion of a gemetric associative r-matrix attached to a genus one fibration with a section and irreducible fibres. It allows us to study degenerations of solutions of the classical Yang-Baxter ... -
Very general monomial valuations of P2 and a Nagata type conjecture
[OWP-2013-22] (Mathematisches Forschungsinstitut Oberwolfach, 2013-10-29) -
Virtual Polytopes
[OWP-2015-02] (Mathematisches Forschungsinstitut Oberwolfach, 2015-04-10)Originating in diverse branches of mathematics, from polytope algebra and toric varieties to the theory of stressed graphs, virtual polytopes represent a natural algebraic generalization of convex polytopes. Introduced as ... -
Weak Expansiveness for Actions of Sofic Groups
[OWP-2014-05] (Mathematisches Forschungsinstitut Oberwolfach, 2014-04-25)In this paper, we shall introduce $h$-expansiveness and asymptotical $h$-expansiveness for actions of sofic groups. By the definitions, each h-expansive action of sofic groups is asymptotically $h$-expansive. We show that ... -
Weak*-Continuity of Invariant Means on Spaces of Matrix Coefficients
[OWP-2021-08] (Mathematisches Forschungsinstitut Oberwolfach, 2021-07-13)With every locally compact group $G$, one can associate several interesting bi-invariant subspaces $X(G)$ of the weakly almost periodic functions $\mathrm{WAP}(G)$ on $G$, each of which captures parts of the representation ... -
Weak-duality based adaptive finite element methods for PDE-constrained optimization with pointwise gradient state-constraints
[OWP-2010-15] (Mathematisches Forschungsinstitut Oberwolfach, 2010)Adaptive finite element methods for optimization problems for second order linear elliptic partial di erential equations subject to pointwise constraints on the $\ell^2$-norm of the gradient of the state are considered. ... -
Weakly Complex Homogeneous Spaces
[OWP-2012-04] (Mathematisches Forschungsinstitut Oberwolfach, 2012-04-24)We complete our recent classification of compact inner symmetric spaces with weakly complex tangent bundle by filling up a case which was left open, and extend this classification to the larger category of compact homogeneous ... -
Weighted Fourier inequalities for radial functions
[OWP-2009-26] (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-19)Weighted $L^p(\mathbb{R}^n) \to L^q(\mathbb{R}^n)$ Fourier inequalities are studied. We prove Pitt-Boas type results on integrability with power weights of the Fourier transform of a radial function. -
Weighted Surface Algebras: General Version
[OWP-2019-07] (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-28)We introduce general weighted surface algebras of triangulated surfaces with arbitrarily oriented triangles and describe their basic properties. In particular, we prove that all these algebras, except the singular disc, ... -
A Well-Posedness Result for Viscous Compressible Fluids with Only Bounded Density
[OWP-2018-10] (Mathematisches Forschungsinstitut Oberwolfach, 2018-05-28)We are concerned with the existence and uniqueness of solutions with only bounded density for the barotropic compressible Navier-Stokes equations. Assuming that the initial velocity has slightly sub-critical regularity and ... -
The Weyl group of the Cuntz algebra
[OWP-2011-31] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-28)The Weyl group of the Cuntz algebra $\mathcal{O}_n$ is investigated. This is (isomorphic to) the group of polynomial automorphisms $\lambda_u$ of $\mathcal{O}_n$, namely those induced by unitaries u that can be written ... -
Weyl-Titchmarsh Functions of Vector-Valued Sturm-Liouville Operators on the Unit Interval
[OWP-2008-13] (Mathematisches Forschungsinstitut Oberwolfach, 2008)The matrix-valued Weyl-Titchmarsh functions $M(\lambda)$ of vector-valued Sturm-Liouville operators on the unit interval with the Dirichlet boundary conditions are considered. The collection of the eigenvalues (i.e., poles ... -
Yet another algorithm for the symmetric eigenvalue problem
[OWP-2016-02] (Mathematisches Forschungsinstitut Oberwolfach, 2016-05-10)In this paper we present a new algorithm for solving the symmetric matrix eigenvalue problem that works by first using a Cayley transformation to convert the symmetric matrix into a unitary one and then uses Gragg’s ... -
Z2-Thurston Norm and Complexity of 3-Manifolds, II
[OWP-2017-36] (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-20)In this sequel to earlier papers by three of the authors, we obtain a new bound on the complexity of a closed 3-manifold, as well as a characterisation of manifolds realising our complexity bounds. As an application, we ... -
Zeta functions of 3-dimensional p-adic Lie algebras
[OWP-2007-10] (Mathematisches Forschungsinstitut Oberwolfach, 2007-03-26)We give an explicit formula for the subalgebra zeta function of a general 3-dimensional Lie algebra over the $p$-adic integers $\mathbb{Z}_p$. To this end, we associate to such a Lie algebra a ternary quadratic form over ...