Iterate on initial states

Iterate final states

The minimization algorithms operate on a DFA plus an optional initial refinement (state that must be distinguished, because of some external properties not observable from the labelled transitions alone).

If no refinements are needed, the minimum implementation is just: let refinements ~refine:_ = ()

Otherwise, the refinements function should invoke the refine function for each set of equivalent states and call the iter for each equivalent state.

E.g if our automata has 5 states, and states 2 and 3 have tag A while states 4 and 5 have tag B, we will do:

let refinements ~refine = refine (fun ~iter -> iter 2; 3); refine (fun ~iter -> iter 4; 5)