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Deformations and desingularizations of conically singular associative submanifolds

Gorapada Bera

Geometry & Topology 30 (2026) 1371–1449
DOI: 10.2140/gt.2026.30.1371
Abstract

The proposals of Joyce (2018) and Doan and Walpuski (2019) on counting closed associative submanifolds of G2-manifolds depend on various conjectural transitions. This article contributes to the study of transitions arising from the degenerations of associative submanifolds into conically singular (CS) associative submanifolds. First, we study the moduli space of CS associative submanifolds with isolated singularities modeled on associative cones in 7, establishing transversality results in both fixed and one-parameter families of coclosed G2-structures. We prove that for a generic coclosed G2-structure (or a generic path thereof) there are no CS associative submanifolds having singularities modeled on cones with stability index greater than 0 (or 1, respectively). We establish that associative cones whose links are null-torsion holomorphic curves in S6 have stability index greater than 4, and all special Lagrangian cones in 3 have stability index greater than or equal to 1 with equality only for the Harvey–Lawson T2-cone and a transverse pair of planes. Next, we study the desingularizations of CS associative submanifolds in a one-parameter family of coclosed G2-structures. Consequently, we derive desingularization results relating the above transitions for CS associative submanifolds with a Harvey–Lawson T2-cone singularity and for associative submanifolds with a transverse self-intersection.

Keywords
conically singular associative, desingularization, deformation, G2 manifolds, counting associative
Mathematical Subject Classification
Primary: 32Q65, 53C25, 53C29, 53C38, 53C40
Secondary: 32Q60, 58C15, 58K60, 58K65
References
Publication
Received: 15 November 2023
Revised: 1 August 2025
Accepted: 15 October 2025
Published: 9 July 2026
Proposed: Simon Donaldson
Seconded: Mark Gross, Jianfeng Lin
Authors
Gorapada Bera
Simons Center for Geometry and Physics
Stony Brook University
Stony Brook, NY
United States

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