We consider termination of the STRS with no additional rule schemes: Signature: cons :: t -> f -> f heightf :: f -> N heightt :: t -> N leaf :: t max :: N -> N -> N nil :: f node :: f -> t s :: N -> N z :: N Rules: heightf(nil) -> z heightf(cons(X, Y)) -> max(heightt(X), heightf(Y)) heightt(leaf) -> z heightt(node(U)) -> s(heightf(U)) The system is accessible function passing by a sort ordering that equates all sorts. We start by computing the initial DP problem D1 = (P1, R, f, c), where: P1. (1) heightf#(cons(X, Y)) => heightt#(X) (2) heightf#(cons(X, Y)) => heightf#(Y) (3) heightt#(node(U)) => heightf#(U) ***** We apply the Subterm Criterion Processor on D1 = (P1, R, f, c). We use the following projection function: nu(heightf#) = 1 nu(heightt#) = 1 We thus have: (1) cons(X, Y) |>| X (2) cons(X, Y) |>| Y (3) node(U) |>| U All DPs are strictly oriented, and may be removed. Hence, this DP problem is finite. Processor output: { }.