merge Cons x xs Nil Cons x xs merge Cons x' xs' Cons x xs merge[Ite] <= x' x Cons x' xs' Cons x xs merge Nil ys ys goal xs ys merge xs ys <= S x S y <= x y <= 0 y True <= S x 0 False merge[Ite] False xs' Cons x xs Cons x merge xs' xs merge[Ite] True Cons x xs ys Cons x merge xs ys <= 2 merge[Ite] 3 True 0 S 1 Cons 2 Nil 0 0 0 merge 2 goal 2 False 0 INNERMOST Frederiksen_Glenstrup/mergelists.tml.trs