match tty with (* some inductive type *)
(C.MutInd (turi,typeno,exp_named_subst))
| (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->
match tty with (* some inductive type *)
(C.MutInd (turi,typeno,exp_named_subst))
| (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->