fact: Fixpoint is_can (s : skel) : Can s -> Prop := match s as s0 return (Can s0 -> Prop) with | PROP => fun X : term -> Prop => is_cand X | PROD s1 s2 => fun C : Can s1 -> Can s2 => forall X : Can s1, is_can s1 X -> eq_can s1 X X -> is_can s2 (C X) end.
imports: Termes Conv Types Class