fact: Definition K3 := Conc (Star a) (Conc b (Star (Plus c (Conc d (Conc (Star a) b))))).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegexpBrzozowski(glue gfinset regexp finite_der equiv) RegexpBrzozowski(sim1 sim2)