Canonical Structure seq_ordType := Eval hnf in OrdType (seq T) seq_ordMixin.
End SeqOrd.
(* A trivial total ordering for Unit *)
Section unitOrd.
Let ordtt (x y : unit ) := false.

(* Specifications: *)
Lemma irr_tt : irreflexive ordtt.
Lemma path_last (A : ordType) (s : seq A) x :
path oleq x s -> oleq x (last x s).