Now showing items 37-56 of 341

• #### Cluster structures on simple complex lie groups and the Belavin-Drinfeld classification ﻿

[OWP-2011-10] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-12)
We study natural cluster structures in the rings of regular functions on simple complex Lie groups and Poisson-Lie structutures compatible with these cluster structures. According to our main conjecture, each class in the ...
• #### Cocharacter-closure and spherical buildings ﻿

[OWP-2015-12] (Mathematisches Forschungsinstitut Oberwolfach, 2015-07-29)
Let $k$ be a field, let $G$ be a reductive $k$-group and $V$ an affine $k$-variety on which $G$ acts. In this note we continue our study of the notion of cocharacter-closed $G(k)$-orbits in $V$. In earlier work we used a ...
• #### Cocharacter-Closure and the Rational Hilbert-Mumford Theorem ﻿

[OWP-2014-16] (Mathematisches Forschungsinstitut Oberwolfach, 2014-12-20)
For a field $k$, let $G$ be a reductive $k$-group and $V$ an affine $k$-variety on which $G$ acts. Using the notion of cocharacter-closed $G(k)$-orbits in $V$ , we prove a rational version of the celebrated Hilbert-Mumford ...
• #### Cocycle Superrigidity and Group Actions on Stably Finite C*-Algebras ﻿

[OWP-2017-01] (Mathematisches Forschungsinstitut Oberwolfach, 2017-01-17)
• #### Congruences Associated with Families of Nilpotent Subgroups and a Theorem of Hirsch ﻿

[OWP-2019-16] (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-27)
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 ...
• #### A construction of hyperbolic Coxeter groups ﻿

[OWP-2010-04] (Mathematisches Forschungsinstitut Oberwolfach, 2010)
We give a simple construction of Gromov hyperbolic Coxeter groups of arbitrarily large virtual cohomological dimension. Our construction provides new examples of such groups. Using this one can construct e.g. new groups ...
• #### The contact polytope of the leech lattice ﻿

[OWP-2009-18] (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-12)
The contact polytope of a lattice is the convex hull of its shortest vectors. In this paper we classify the facets of the contact polytope of the Leech lattice up to symmetry. There are 1, 197, 362, 269, 604, 214, 277, 200 ...
• #### Contractive Idempotents on Locally Compact Quantum Groups ﻿

[OWP-2012-19] (Mathematisches Forschungsinstitut Oberwolfach, 2012)
A general form of contractive idempotent functionals on coamenable locally compact quantum groups is obtained, generalising the result of Greenleaf on contractive measures on locally compact groups. The image of a convolution ...
• #### Control of Volterra systems with scalar kernels ﻿

[OWP-2009-16] (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-10)
Volterra observations systems with scalar kernels are studied. New sufficient conditions for admissibility of observation operators are developed and some examples are discussed.
• #### Counting Curves on Toric Surfaces Tropical Geometry & the Fock Space ﻿

[OWP-2017-18] (Mathematisches Forschungsinstitut Oberwolfach, 2017-07-17)
We study the stationary descendant Gromov–Witten theory of toric surfaces by combining and extending a range of techniques – tropical curves, floor diagrams, and Fock spaces. A correspondence theorem is established between ...
• #### Coxeter Arrangements and Solomon's Descent Algebra ﻿

[OWP-2011-03] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-6)
• #### Criteria for Algebraicity of Analytic Functions ﻿

[OWP-2018-25] (Mathematisches Forschungsinstitut Oberwolfach, 2018-11-12)
We consider functions defined on an open subset of a nonsingular, either real or complex, algebraic set. We give criteria for an analytic function to be a Nash (resp. regular, resp. polynomial) function. Our criteria depend ...
• #### Cryptanalysis of Public-key Cryptosystems Based on Algebraic Geometry Codes ﻿

[OWP-2012-01] (Mathematisches Forschungsinstitut Oberwolfach, 2012-03-20)
This paper addresses the question of retrieving the triple $(\mathcal{X},\mathcal{P},\mathcal{E})$ from the algebraic geometry code $\mathcal{C}_L(\mathcal{X},\mathcal{P},\mathcal{E})$, where $\mathcal{X}$ is an algebraic ...
• #### Crystal energy functions via the charge in types A and C ﻿

[OWP-2011-25] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-23)
The Ram-Yip formula for Macdonald polynomials (at $t=0$) provides a statistic which we call charge. In types $A$ and $C$ it can be defined on tensor products of Kashiwara-Nakashima single column crystals. In this ...