proposition: Lemma bigcap_setI_l {U T} (s1 s2 : set U) (f : U -> set T) : bigcap (s1 :|: s2) f <--> bigcap s1 f :&: bigcap s2 f.
proof: Proof. firstorder. Qed.
imports: mathcomp.ssreflect.ssreflect Classes.RelationClasses Classes.Morphisms List Tactics mathcomp(ssrfun ssrbool ssrnat seq)