YES TRS: active(f(f(a()))) -> mark(c(f(g(f(a()))))) mark(f(X)) -> active(f(mark(X))) mark(a()) -> active(a()) mark(c(X)) -> active(c(X)) mark(g(X)) -> active(g(mark(X))) f(mark(X)) -> f(X) f(active(X)) -> f(X) c(mark(X)) -> c(X) c(active(X)) -> c(X) g(mark(X)) -> g(X) g(active(X)) -> g(X) max/plus interpretations on N: active_A(x1) = max{11, x1} active#_A(x1) = max{70, 31 + x1} f_A(x1) = max{33, 10 + x1} f#_A(x1) = max{93, 33 + x1} a_A = 42 a#_A = 92 mark_A(x1) = max{1, x1} mark#_A(x1) = max{68, 61 + x1} c_A(x1) = max{6, 12} c#_A(x1) = max{0, 1 + x1} g_A(x1) = max{30, 8 + x1} g#_A(x1) = max{68, 67} precedence: mark > c > active > g > f > a