Flops of G-Hilb and equivalences of derived categories by variation of GIT quotient

Abstract

For a finite subgroup G⊂SL(3,ℂ), Bridgeland, King, and Reid [BKR] proved that the moduli space of G-clusters is a crepant resolution of the quotient ℂ³/G . This paper considers the moduli spaces $\mathcal{M}$_θ, introduced by Kronheimer and further studied by Sardo Infirri, which coincide with G-Hilb for a particular choice of geometric invariant theory (GIT) parameter θ. For G Abelian, we prove that every projective crepant resolution of ℂ³/G is isomorphic to $\mathcal{M}$_θ for some parameter θ. The key step is the description of GIT chambers in terms of the K-theory of the moduli space via the appropriate Fourier-Mukai transform. We also uncover explicit equivalences between the derived categories of moduli $\mathcal{M}$_θ for parameters lying in adjacent GIT chambers.