Zobrazeno 1 - 10
of 3 495
pro vyhledávání: '"Steirteghem, A."'
We classify the compact, connected multiplicity free Hamiltonian U(2)-manifolds with trivial principal isotropy group whose momentum polytope is a triangle.
Comment: v1: 26 pages. v2: 34 pages, added section on invariant complex structures, impr
Comment: v1: 26 pages. v2: 34 pages, added section on invariant complex structures, impr
Externí odkaz:
http://arxiv.org/abs/2208.02099
Autor:
Paulus, Kay, Van Steirteghem, Bart
Let K be a simple and simply connected compact Lie group. We call a (twisted) quasi-Hamiltonian K-manifold M a quasi-Hamiltonian model space if it is multiplicity free and its momentum map is surjective. We explicitly identify the subgroups of the Li
Externí odkaz:
http://arxiv.org/abs/1901.00634
Publikováno v:
Selecta Mathematica New Series 26, Article number: 27 (2020)
We apply the combinatorial theory of spherical varieties to characterize the momentum polytopes of polarized projective spherical varieties. This enables us to derive a classification of these varieties, without specifying the open orbit, as well as
Externí odkaz:
http://arxiv.org/abs/1809.08171
Let G be a complex connected reductive group. I. Losev has shown that a smooth affine spherical G-variety X is uniquely determined by its weight monoid, which is the set of irreducible representations of G that occur in the coordinate ring of X. In t
Externí odkaz:
http://arxiv.org/abs/1705.05357
Autor:
Pezzini, Guido, Van Steirteghem, Bart
Let G be a connected complex reductive group. A well known theorem of I. Losev's says that a smooth affine spherical G-variety X is uniquely determined by its weight monoid, which is the set of irreducible representations of G that occur in the coord
Externí odkaz:
http://arxiv.org/abs/1510.04266
We determine, under a certain assumption, the Alexeev-Brion moduli scheme M_S of affine spherical G-varieties with a prescribed weight monoid S. In [ arXiv:1008.0911 ] we showed that if G is a connected complex reductive group of type A and S is the
Externí odkaz:
http://arxiv.org/abs/1505.07446
Publikováno v:
Linear Algebra and its Applications, 546 (2018) 210-260
The Jordan type of a nilpotent matrix is the partition giving the sizes of its Jordan blocks. We study pairs of partitions $(P,Q)$, where $Q={\mathcal Q}(P)$ is the Jordan type of a generic nilpotent matrix A commuting with a nilpotent matrix B of Jo
Externí odkaz:
http://arxiv.org/abs/1409.2192
Autor:
Bravi, Paolo, Van Steirteghem, Bart
Publikováno v:
Int. Math. Res. Not. 2016 (2016), 4544-4587
We study Alexeev and Brion's moduli scheme $M_\Gamma$ of affine spherical varieties with weight monoid $\Gamma$ under the assumption that $\Gamma$ is free. We describe the tangent space to $M_\Gamma$ at its `most degenerate point' in terms of the com
Externí odkaz:
http://arxiv.org/abs/1406.6041
Autor:
Meyns, Pieter, van der Spank, Judith, Capiau, Hanne, De Cock, Lieve, Van Steirteghem, Eline, Van der Looven, Ruth, Van Waelvelde, Hilde
Publikováno v:
In International Journal of Human - Computer Studies February 2019 122:90-102
Publikováno v:
Ann. Inst. Fourier (Grenoble) 62 (2012) 1765-1809
Let G be a complex reductive algebraic group. Fix a Borel subgroup B of G, with unipotent radical U, and a maximal torus T in B with character group X(T). Let S be a submonoid of X(T) generated by finitely many dominant weights. V. Alexeev and M. Bri
Externí odkaz:
http://arxiv.org/abs/1008.0911