Untangle is a Lean4 widget that displays string diagrams for morphisms inside categories and allows you to rewrite expressions by clicking on natural transformations and morphisms in the string diagram.
This widget currently has rewrite rules for Monads. Next, I'd like to add rules for symmetric monoidal categories and bimonoids/Hopf algebras.
Open the Example.lean file and follow the instructions
- This proof of concept is work in progress and is not yet ready for general purpose use.