Now showing items 175-194 of 377

• #### The Magic Square of Reflections and Rotations ﻿

[OWP-2018-13] (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-01)
We show how Coxeter’s work implies a bijection between complex reflection groups of rank two and real reflection groups in 0(3). We also consider this magic square of reflections and rotations in the framework of Clifford ...
• #### The Martin Boundary of Relatively Hyperbolic Groups with Virtually Abelian Parabolic Subgroups ﻿

[OWP-2018-03] (Mathematisches Forschungsinstitut Oberwolfach, 2018-03-19)
Given a probability measure on a finitely generated group, its Martin boundary is a way to compactify the group using the Green's function of the corresponding random walk. We give a complete topological characterization ...
• #### Matchings and Squarefree Powers of Edge Ideals ﻿

[OWP-2019-25] (Mathematisches Forschungsinstitut Oberwolfach, 2019-11-11)
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 ...
• #### Matrix Elements of Irreducible Representations of SU(n+1) x SU(n+1) and Multivariable Matrix-Valued Orthogonal Polynomials ﻿

[OWP-2017-16] (Mathematisches Forschungsinstitut Oberwolfach, 2017-06-14)
In Part 1 we study the spherical functions on compact symmetric pairs of arbitrary rank under a suitable multiplicity freeness assumption and additional conditions on the branching rules. The spherical functions are ...
• #### Max-Linear Models on Infinite Graphs Generated by Bernoulli Bond Percolation ﻿

[OWP-2018-09] (Mathematisches Forschungsinstitut Oberwolfach, 2018-05-17)
We extend previous work of max-linear models on finite directed acyclic graphs to infinite graphs, and investigate their relations to classical percolation theory. We formulate results for the oriented square lattice graph ...
• #### Maximal Cohen-Macaulay modules over non-isolated surface singularities and matrix problems ﻿

[OWP-2015-06] (Mathematisches Forschungsinstitut Oberwolfach, 2015-05-13)
In this article we develop a new method to deal with maximal Cohen-Macaulay modules over non-isolated surface singularities. In particular, we give a negative answer on an old question of Schreyer about surface singularities ...
• #### 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.
• #### A McKay Correspondence for Reflection Groups ﻿

[OWP-2018-14] (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-02)
We construct a noncommutative desingularization of the discriminant of a finite reflection group $G$ as a quotient of the skew group ring $A=S*G$. If $G$ is generated by order two reflections, then this quotient identifies ...
• #### The McKay-conjecture for exceptional groups and odd primes ﻿

[OWP-2007-07] (Mathematisches Forschungsinstitut Oberwolfach, 2007)
Let $\mathbf{G}$ be a simply-connected simple algebraic group over an algebraically closed field of characteristic p with a Frobenius map $F:\mathbf{G}→\mathbf{G}$ and $\mathbf{G}:=\mathbf{G}^F$, such that the root system ...
• #### Mehler-Heine asymptotics of a class of generalized hypergeometric polynomials : ﻿

[OWP-2013-23] (Mathematisches Forschungsinstitut Oberwolfach, 2013-10-29)
We obtain a Mehler–Heine type formula for a class of generalized hypergeometric polynomials. This type of formula describes the asymptotics of polynomials scale conveniently. As a consequence of this formula, we obtain ...
• #### Mesh Ratios for Best-Packing and Limits of Minimal Energy Configurations ﻿

[OWP-2013-13] (Mathematisches Forschungsinstitut Oberwolfach, 2013-06-10)
For $N$-point best-packing configurations $\omega_N$ on a compact metric space $(A, \rho)$, we obtain estimates for the mesh-separation ratio $\gamma(\rho_N , A)$, which is the quotient of the covering radius of $\omega_N$ ...
• #### Metric Connections with Parallel Skew-Symmetric Torsion ﻿

[OWP-2018-16] (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-16)
A geometry with parallel skew-symmetric torsion is a Riemannian manifold carrying a metric connection with parallel skew-symmetric torsion. Besides the trivial case of the Levi-Civita connection, geometries with non-vanishing ...
• #### Milnor fibre homology via deformation ﻿

[OWP-2015-22] (Mathematisches Forschungsinstitut Oberwolfach, 2015)
In case of one-dimensional singular locus, we use deformations in order toget refined information about the Betti numbers of the Milnor fibre.
• #### Minimal Codimension One Foliation of a Symmetric Space by Damek-Ricci Spaces ﻿

[OWP-2019-11] (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-07)
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 $A$ ...
• #### The Minimal Resolution Conjecture on a general quartic surface in $\mathbb P^3$ ﻿

[OWP-2017-21] (Mathematisches Forschungsinstitut Oberwolfach, 2017-07-27)
Mustaţă has given a conjecture for the graded Betti numbers in the minimal free resolution of the ideal of a general set of points on an irreducible projective algebraic variety. For surfaces in $\mathbb P^3$ this conjecture ...
• #### Minimal Riesz energy on the sphere for axis-supported external fields ﻿

[OWP-2009-04] (Mathematisches Forschungsinstitut Oberwolfach, 2009)
Abstract. We investigate the minimal Riesz $s$-energy problem for positive measures on the d-dimensional unit sphere $\mathbb{S}^d$ in the presence of an external field induced by a point charge, and more generally by ...
• #### Module Categories for Group Algebras over Commutative Rings ﻿

[OWP-2012-12] (Mathematisches Forschungsinstitut Oberwolfach, 2012-10-01)
We develop a suitable version of the stable module category of a finite group $G$ over an arbitrary commutative ring $k$. The purpose of the construction is to produce a compactly generated triangulated category whose ...
• #### Monoid valuations and value ordered supervaluations ﻿

[OWP-2011-17] (Mathematisches Forschungsinstitut Oberwolfach, 2011)
We complement two papers on supertropical valuation theory ([IKR1], [IKR2]) by providing natural examples of m-valuations (= monoid valuations), after that of supervaluations and transmissions between them. The supervaluations ...
• #### MOSES: A Streaming Algorithm for Linear Dimensionality Reduction ﻿

[OWP-2018-12] (Mathematisches Forschungsinstitut Oberwolfach, 2018-06-26)
This paper introduces Memory-limited Online Subspace Estimation Scheme (MOSES) for both estimating the principal components of data and reducing its dimension. More specifically, consider a scenario where the data vectors ...
• #### Multiple Bernoulli series and volumes of moduli spaces of flat bundles over surfaces ﻿

[OWP-2013-04] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
Using Szenes formula for multiple Bernoulli series, we explain how to compute Witten series associated to classical Lie algebras. Particular instances of these series compute volumes of moduli spaces of flat bundles over ...