349 citations · 541 across the 25 of their papers we have counts for
25 papers
Moduli and periods of simply connected Enriques surfaces
T. Ekedahl, J. M. E. Hyland, N. I. Shepherd-Barron
We describe a period map for those simply connected Enriques surfaces in characteristic 2 whose canonical double cover is K3. The moduli stack for these surfaces has a Deligne-Mumf…
Cycle classes on the moduli of K3 surfaces in positive characteristic
Torsten Ekedahl, Gerard van der Geer
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 i…
Approximating classifying spaces by smooth projective varieties
Torsten Ekedahl
We prove that for every reductive algebraic group with centre of positive dimension and every integer there is a smooth and projective variety and an algebraic -tors…
The Grothendieck group of algebraic stacks
Torsten Ekedahl
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 local…
A geometric invariant of a finite group
Torsten Ekedahl
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 e…
First steps towards total reality of meromorphic functions
T. Ekedahl, B. Shapiro, M. Shapiro
It was earlier conjectured by the second and the third authors that any rational curve such that the inverse images of all its flattening point…