YES TRS: active(f(X)) -> mark(g(h(f(X)))) mark(f(X)) -> active(f(mark(X))) mark(g(X)) -> active(g(X)) mark(h(X)) -> active(h(mark(X))) f(mark(X)) -> f(X) f(active(X)) -> f(X) g(mark(X)) -> g(X) g(active(X)) -> g(X) h(mark(X)) -> h(X) h(active(X)) -> h(X) max/plus interpretations on N: active_A(x1) = max{0, x1} active#_A(x1) = max{8, 4 + x1} f_A(x1) = max{9, 6 + x1} f#_A(x1) = max{0, 3} mark_A(x1) = max{0, 1 + x1} mark#_A(x1) = max{7, 6 + x1} g_A(x1) = max{2, -2} g#_A(x1) = max{8, 1} h_A(x1) = max{3, x1} h#_A(x1) = max{9, 7} precedence: g > mark > active = f > h