On deformations of triangulated models

TL;DR

This paper investigates deformations of triangulated categories, focusing on dg and A-infinity models, and introduces a curvature compensating deformation framework applicable to various derived and related categories.

Contribution

It provides a new understanding of deformations of triangulated models via twisted objects and identifies conditions preserving model structures under deformation.

Findings

Describes curvature compensating deformations for Hochschild 2 cocycles.

Applies the theory to derived A-infinity and abelian categories.

Identifies a purity condition ensuring structural preservation during deformation.

Abstract

This paper is the first part of a project aimed at understanding deformations of triangulated categories, and more precisely their dg and A infinity models, and applying the resulting theory to the models occurring in the Homological Mirror Symmetry setup. In this first paper, we focus on models of derived and related categories, based upon the classical construction of twisted objects over a dg or $A_{\infty}$-algebra. For a Hochschild 2 cocycle on such a model, we describe a corresponding "curvature compensating" deformation which can be entirely understood within the framework of twisted objects. We unravel the construction in the specific cases of derived A infinity and abelian categories, homotopy categories, and categories of graded free qdg-modules. We identify a purity condition on our models which ensures that the structure of the model is preserved under deformation. This condition is typically fulfilled for homotopy categories, but not for unbounded derived categories.