May 2025: Focused on correctness and expressiveness in the Agda categories library (agda/agda-categories). Delivered critical correctness fixes in the category theory module, including a corrected type signature for the distributive law of the product of functors, and a refactor to push-center to align with pull-center by flipping the input direction. Introduced symmetric merge combinators merge₁ʳ and merge₁ˡ, expanding reasoning capabilities and enabling more modular proofs. These changes reduce downstream maintenance risks, improve reliability of category-theory proofs, and extend the library’s compositional capabilities for future abstractions. Technologies and skills demonstrated include advanced type theory, Agda language mastery, refactoring discipline, and rigorous code reviews.

January 2025 monthly summary: Consolidated API stability in agda/agda-categories by fixing the Cocartesian module's export of natural isomorphisms and aligning type signatures with the monoidal structure. This work improves API consistency and reduces downstream type errors for users implementing category-theoretic constructs.

Month: 2024-12. Delivered API refinements in the agda-categories library, focusing on internal API clarity and pushout reasoning to improve maintainability and downstream usability. Implemented a targeted refactor of the up-to-iso signature by removing an unnecessary argument and introduced an IsPushout predicate form by extending the Pushout structure, clarifying usage in the library. These changes streamline category-theory proofs and reduce API surface, enabling safer extensions and fewer mistakes in proofs while supporting long-term contributor onboarding.