A∞ Categories in Lean

Marco David, Jason Dong, Hallvard Hareide, Jasper van de Kreeke, Lillian Liu, Justin Mu, Zhan Shi, Niels Voss, Annie Yao

Repository for the formalization of category theory in Lean, a research project run at UC Berkeley.

Check out the blueprint homepage for this project.

Repository structure

The Lean sources are split into four Lake libraries. Each has a root file (Util.lean, ComputableCochainComplex.lean, AInfinity.lean, KLRW.lean) that imports every file in the corresponding folder; these root files are generated by lake exe mk_all and checked in CI, so rerun that command after adding a file.

FolderContents
Util/Contains a Texify class and the #texify command for rendering terms as LaTeX.
ComputableCochainComplex/Computable categorical constructions: explicit biproducts and zero objects, the computable additive completion CMat_, and bounded cochain complexes.
AInfinity/Gradings and their homomorphisms, graded linear maps, graded linear quivers, the Stasheff identities, A∞-categories, A∞-categories with vanishing higher operations, DG and linear categories as A∞-categories, A∞-functors.
KLRW/KLRW algebras and categories: the general quiver-parametrised KLRW algebra and its -linear category, and a computable special case with one black strand and red strands.

The blueprint sources live in blueprint/src/. The API documentation is built on CI by docgen-action, which generates a docbuild/ project depending on doc-gen4 at the tag of the current Lean toolchain; the checked-in docbuild/lakefile.toml is its local counterpart.

Project metadata and license

formalization.yaml records the project's sources, scope, status, fidelity to the literature, and how it was produced, following the community standards. Please keep it up to date (e.g. the sorry counts and scope) when making significant changes; CI validates it against the schema.

The code is released under the Apache 2.0 license; see LICENSE.