A twist on ring morphisms and crepant contractions

Abstract

Given a surjective ring morphism, this paper constructs the twist functor around the induced derived restriction of scalars functor. We prove that the twist around ring morphisms is a derived autoequivalence in two settings: (1) Twists for Gorenstein orders, (2) twists induced by Frobenius exact categories. As a corollary, it is shown that the noncommutative twist introduced by Donovan and Wemyss is in fact a spherical twist. We then use the technology developed in (1) and (2) to obtain new spherical twists for very singular schemes, and discuss how our result extends previous works on spherical twists induced by crepant contractions.

Theorems & Definitions (177)

• Theorem 1: \ref{['twist t res']}
• Theorem 2: \ref{['spherical condition 4']}
• Theorem 3: \ref{['summary theorem']}
• Theorem 4: \ref{['syz theorem']}
• Theorem 5: \ref{['z local tw and ctw']}
• Theorem 6: \ref{['twist geometric']}
• Definition 2.1
• Remark 2.2
• Definition 2.3: anno
• Lemma 2.4