Definition cntabl(U:Type)(C:Ensemble(Ensemble U)):=
exists f:nat->Ensemble U,forall c,C c->exists i:nat,f i=c.

Lemma aaron_stump_cse545(Q:nat->Prop): (forall n:nat,(forall n':nat,n'<n->Q n')->Q n)-> forall n:nat,forall n':nat,n'<=n->Q n'.