Zobrazeno 1 - 10
of 62
pro vyhledávání: '"Ekedahl, Torsten"'
Autor:
Ekedahl, Torsten, van der Geer, Gerard
This paper provides explicit closed formulas in terms of tautological classes for the cycle classes of the height and Artin invariant strata in families of K3 surfaces. The proof is uniform for all strata and uses a flag space as the computations in
Externí odkaz:
http://arxiv.org/abs/1104.3024
Autor:
Ekedahl, Torsten
We prove that for every reductive algebraic group $H$ with centre of positive dimension and every integer $K$ there is a smooth and projective variety $X$ and an algebraic $H$-torsor $P \to X$ such that the classifying map $X \to \Bclass H$ induces a
Externí odkaz:
http://arxiv.org/abs/0905.1538
Autor:
Ekedahl, Torsten
We study the class of the classifying stack of a finite group in a Grothendieck group of algebraic stacks introduced previously. We show that this class is trivial in a number of examples most notably for all symmetric groups. We also give some examp
Externí odkaz:
http://arxiv.org/abs/0903.3148
Autor:
Ekedahl, Torsten
We introduce a Grothendieck group of algebraic stacks (with affine stabilisers) analogous to the Grothendieck group of algebraic varieties. We then identify it with a certain localisation of the Grothendieck group of algebraic varieties. Several inva
Externí odkaz:
http://arxiv.org/abs/0903.3143
Autor:
Bjorner, Anders, Ekedahl, Torsten
Let (W,S) be a crystallographic Coxeter group (this includes all finite and affine Weyl groups), and J a subset of S. Let $W^J$ denote the set of minimal coset representatives modulo the parabolic subgroup $W_J$. For w in $W^J$, let $f^{w,J}_{i}$ den
Externí odkaz:
http://arxiv.org/abs/math/0508022
Autor:
Ekedahl, Torsten
This is the written version of a talk at the conference on ``Non-commutative geometry and representation theory in mathematical physics'' held in Karlstad, Sweden, 5--10 July, 2004. In it we show that the duality formula of Rocha-Caridi and Wallach i
Externí odkaz:
http://arxiv.org/abs/math/0412286
Autor:
Ekedahl, Torsten, Salomonsson, Pelle
We prove a generalisation to any characteristic of a result of Macdonald that describes strict polynomial functors in characteristic zero in terms of representations of the groupoid of finite sets and bijections. Our result will give an analogous des
Externí odkaz:
http://arxiv.org/abs/math/0412287
Autor:
Ekedahl, Torsten, van der Geer, Gerard
We introduce a stratification on the space of symplectic flags on the de Rham bundle of the universal principally polarized abelian variety in positive characteristic and study its geometric properties like irreducibility of the strata and we calcula
Externí odkaz:
http://arxiv.org/abs/math/0412272
Autor:
Ekedahl, Torsten, Skjelnes, Roy
In the Hilbert scheme of points on a scheme X there is an open subset parameterizing distinct points. The closure of that open set is by definition the good component. When X is flat over the base, we show that a certain blow-up of the symmetric prod
Externí odkaz:
http://arxiv.org/abs/math/0405073
Cycles Representing The Top Chern Class of the Hodge Bundle on the Moduli Space of Abelian Varieties
Autor:
Ekedahl, Torsten, van der Geer, Gerard
We give a generalization to higher genera of the famous formula $12 \lambda=\delta$ for genus 1. We also compute the classes of certain strata in the Satake compactification as elements of the push down of the tautological ring.
Comment: 10 page
Comment: 10 page
Externí odkaz:
http://arxiv.org/abs/math/0402274