Module OrderedTypeLists (O:OrderedType).
Local Notation In:=(InA O.eq).
Local Notation Inf:=(lelistA O.lt).
Local Notation Sort:=(sort O.lt).
Local Notation NoDup:=(NoDupA O.eq).
Notation Sort := (sort ltk).
Notation Inf := (lelistA ltk).

Lemma Inf_eq l x x' : eqk x x' -> Inf x' l -> Inf x l.