Module Import GenHigh := GenHighImpl.Impl GenLow.

Lemma semFreq :
forall {A : Type} (ng : nat * G A) (l : seq (nat * G A)),
List.Forall (fun x => x.1 > 0) (ng :: l) ->
semGen (freq ((fst ng, snd ng) ;; l)) <-->
\bigcup_(x in (ng :: l)) semGen x.2.