fact: Definition fhrel_rdv (e1 : {fhrel B & A}) (e2 : {fhrel C & A}) : {fhrel C & B} := fun j i => [forall k, e1 i k ==> e2 j k].
imports: Setoid Morphisms kat normalisation rewriting kat_tac comparisons rel relalg boolean mathcomp(all_ssreflect)