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Foundations of $(A_\infty,2)$-categories: from flow to linear

Nathaniel Bottman, Katrin Wehrheim

TL;DR

The paper develops a rigorous algebraic and topological framework for a symplectic $(A_ fty,2)$-category, termed $\oldsymbol{\mathsf{Symp}}$, by introducing $(A_ ablafty,2)$-flow categories and linear $(A_ ablafty,2)$-categories. It fixes limitations of earlier Bottman–Carmeli definitions by extending 2-associahedra to include all relevant fiber-product faces and attaching operations to cellular chains, enabling single-arity operations governed by $(A_ ablafty,2)$-equations. A key result is that any regularized $(A_ ablafty,2)$-flow category yields a linear $(A_ ablafty,2)$-category, with the motivating example $\ ext{Symp}$ built from moduli of pseudoholomorphic quilts and regularization data. The framework aims to unify symplectic field theory constructions, Fukaya-categorical functoriality, and mirror-symmetric phenomena, while accounting for figure-eight bubbling and curvature terms via Novikov counts. This provides a principled route to a full symplectic $(A_ ablafty,2)$-category and potentially higher $(A_ ablafty,n)$-categorical structures, with broad implications for Floer theory, topological invariants, and HMS proofs.

Abstract

This paper provides a blueprint for the construction of a symplectic $(A_\infty,2)$-category, $\mathsf{Symp}$. We develop two ways of encoding the information in $\mathsf{Symp}$ -- one topological, one algebraic. The topological encoding is as an $(A_\infty,2)$-flow category, which we define here. The algebraic encoding is as a linear $(A_\infty,2)$-category, which we extract from the topological encoding. In upcoming work, we plan to use the adiabatic Fredholm theory developed by us to construct $\mathsf{Symp}$ as an $(A_\infty,2)$-flow category, which thus induces a linear $(A_\infty,2)$-category. The notion of a linear $(A_\infty,2)$-category developed here goes beyond the proposal of Bottman and Carmeli. The recursive structure of the 2-associahedra identifies faces with fiber products of 2-associahedra over associahedra, which led Bottman and Carmeli to associate operations to singular chains on 2-associahedra. The innovation in our new definition of linear $(A_\infty,2)$-category is to extend the family of 2-associahedra to include all fiber products of 2-associahedra over associahedra. This allows us to associate operations to cellular chains, which in particular enables us to produce a definition that involves only one operation in each arity, governed by a collection of $(A_\infty,2)$-equations.

Foundations of $(A_\infty,2)$-categories: from flow to linear

TL;DR

The paper develops a rigorous algebraic and topological framework for a symplectic -category, termed , by introducing -flow categories and linear -categories. It fixes limitations of earlier Bottman–Carmeli definitions by extending 2-associahedra to include all relevant fiber-product faces and attaching operations to cellular chains, enabling single-arity operations governed by -equations. A key result is that any regularized -flow category yields a linear -category, with the motivating example built from moduli of pseudoholomorphic quilts and regularization data. The framework aims to unify symplectic field theory constructions, Fukaya-categorical functoriality, and mirror-symmetric phenomena, while accounting for figure-eight bubbling and curvature terms via Novikov counts. This provides a principled route to a full symplectic -category and potentially higher -categorical structures, with broad implications for Floer theory, topological invariants, and HMS proofs.

Abstract

This paper provides a blueprint for the construction of a symplectic -category, . We develop two ways of encoding the information in -- one topological, one algebraic. The topological encoding is as an -flow category, which we define here. The algebraic encoding is as a linear -category, which we extract from the topological encoding. In upcoming work, we plan to use the adiabatic Fredholm theory developed by us to construct as an -flow category, which thus induces a linear -category. The notion of a linear -category developed here goes beyond the proposal of Bottman and Carmeli. The recursive structure of the 2-associahedra identifies faces with fiber products of 2-associahedra over associahedra, which led Bottman and Carmeli to associate operations to singular chains on 2-associahedra. The innovation in our new definition of linear -category is to extend the family of 2-associahedra to include all fiber products of 2-associahedra over associahedra. This allows us to associate operations to cellular chains, which in particular enables us to produce a definition that involves only one operation in each arity, governed by a collection of -equations.

Paper Structure

This paper contains 17 sections, 6 theorems, 71 equations, 2 figures.

Key Result

Lemma 2.7

Let $Y_n$ for $1\leq n \leq N$ be $0$-dimensional $\mathcal{C}^0$-manifolds equipped with energy functions $\mathcal{E}_n: Y_n\to\mathbb{R}$ as in Definition def:Novikov count. Define an energy function $Y:=Y_1\times \ldots\times Y_N \to \mathbb{R}$ by addition $(y_1,\ldots,y_N)\mapsto \mathcal{E}_1

Figures (2)

  • Figure 1: Here we depict the codimension-1 degenerations in an element of $\mathscr{O}$ in a heuristic fashion. On the left is a representative element of a fiber product of 2-associahedra. There are three types of codimension-1 degenerations, which are depicted from left to right on the right-hand side: marked points on a single seam on a single sphere can collide; a proper subset of seams on all spheres can collide; or marked points on a single sphere can diverge to infinity -- which is equivalent to all seams on a single sphere colliding. For details see Remark \ref{['rmk:three_types_of_comp_maps']}.
  • Figure :

Theorems & Definitions (41)

  • Remark 1.1
  • Remark 1.2
  • Definition 2.1
  • Definition 2.2
  • Definition 2.3
  • Remark 2.4
  • Definition 2.5
  • Remark 2.6
  • Lemma 2.7
  • proof
  • ...and 31 more