fact: Definition insert n1 h1 := let fix insert_aux l2 := match l2 with | nil (h2,n2) => match compare h1 h2 with | Eq => nil (h1,Pplus n1 n2) | Lt => (h1,n1):: nil (h2,n2) | Gt => (h2,n2):: nil (h1,n1) end | (h2,n2)::t2 => match compare h1 h2 with | Eq => (h1,Pplus n1 n2):: t2 | Lt => (h1,n1)::l2 | Gt => (h2,n2)::insert_aux t2 end end in insert_aux.
imports: Coq(Arith NArith List RelationClasses)