A proof of Kontsevich-Soibelman conjecture
Alexander I. Efimov
TL;DR
The paper proves the Kontsevich–Soibelman conjecture for essentially small $A_{ ablafty}$-(pre-)categories over a field, establishing a bijection between their quasi-equivalence classes and those of essentially small $A_{ ablafty}$-categories with identities. It introduces minimal models and Hochschild cohomology for graded pre-categories, proves a Main Lemma ensuring invariance of Hochschild cohomology under graded-pre-category equivalences, and develops obstruction theory to transfer $A_{ ablafty}$-structures across equivalences. A robust theory of twisted complexes over $A_{ ablafty}$-pre-categories is developed, yielding a quasi-equivalence-invariant pre-triangulated envelope and aligning with the classical twisted complexes for ordinary $A_{ ablafty}$-categories. The results justify replacing Fukaya $A_{ ablafty}$-pre-categories with quasi-equivalent actual $A_{ ablafty}$-categories, with implications for homological mirror symmetry and categorical constructions in symplectic geometry.
Abstract
It is well known that "Fukaya category" is in fact an $A_{\infty}$-pre-category in sense of Kontsevich and Soibelman \cite{KS}. The reason is that in general the morphism spaces are defined only for transversal pairs of Lagrangians, and higher products are defined only for transversal sequences of Lagrangians. In \cite{KS} it is conjectured that for any graded commutative ring $k,$ quasi-equivalence classes of $A_{\infty}$-pre-categories over $k$ are in bijection with quasi-equivalence classes of $A_{\infty}$-categories over $k$ with strict (or weak) identity morphisms. In this paper we prove this conjecture for essentially small $A_{\infty}$-(pre-)categories, in the case when $k$ is a field. In particular, it follows that we can replace Fukaya $A_{\infty}$-pre-category with a quasi-equivalent actual $A_{\infty}$-category. We also present natural construction of pre-triangulated envelope in the framework of $A_{\infty}$-pre-categories. We prove its invariance under quasi-equivalences.
