Comparison theorems for deformation functors via invariant theory

Abstract

We compare deformations of algebras to deformations of schemes in the setting of invariant theory. Our results generalize comparison theorems of Schlessinger and the second author for projective schemes. We consider deformations (abstract and embedded) of a scheme $X$ which is a good quotient of a quasi-affine scheme $X^{\prime }$ by a linearly reductive group $G$ and compare them to invariant deformations of an affine $G$-scheme containing $X^{\prime }$ as an open invariant subset. The main theorems give conditions for when the comparison morphisms are smooth or isomorphisms.

Minor improvements and corrections. Improved presentation. Changed some definitions and terms

References in corpus (1)

• Deformations of Smooth Toric Surfaces

Cited by in corpus (2)

• On smooth Fano fourfolds of Picard number two
• Unobstructed Stanley-Reisner Degenerations for Dual Quotient Bundles on $G(2,n)$