0000000000427174
AUTHOR
Christoph Sorger
La singularité de O’Grady
Let M 2 v M_{2v} be the moduli space of semistable sheaves with Mukai vector 2 v 2v on an abelian or K 3 K3 surface where v v is primitive such that ⟨ v , v ⟩ = 2 \langle v,v \rangle =2 . We show that the blow-up of the reduced singular locus of M 2 v M_{2v} provides a symplectic resolution of singularities. This provides a direct description of O’Grady’s resolutions of M K 3 ( 2 , 0 , 4 ) M_{K3}(2,0,4) and M A b ( 2 , 0 , 2 ) M_{Ab}(2,0,2) . Résumé. Soit M 2 v M_{2v} l’espace de modules des faisceaux semi-stables de vecteur de Mukai 2 v 2v sur une surface K 3 K3 ou abélienne où v v est primitif tel que ⟨ v , v ⟩ = 2 \langle v,v \rangle =2 . Nous montrons que l’éclatement de M 2 v M_{2v} le…
The cup product of Hilbert schemes for K3 surfaces
To any graded Frobenius algebra A we associate a sequence of graded Frobenius algebras A [n] so that there is canonical isomorphism of rings (H *(X;ℚ)[2]) [n] ≅H *(X [n] ;ℚ)[2n] for the Hilbert scheme X [n] of generalised n-tuples of any smooth projective surface X with numerically trivial canonical bundle.