KAT-ML: an interactive theorem prover for Kleene algebra with tests

We describe KAT-ML, an implementation of an interactive theorem prover for Kleene algebra with tests (KAT). The system is designed to reflect the natural style of reasoning with KAT that one finds in the literature. One can also use the system to reason about properties of simple imperative programs using schematic KAT (SKAT). We explain how the system works and illustrate its use with some examples, including an extensive scheme equivalence proof.