YES TRS: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) max/plus interpretations on N: f_A(x1,x2) = max{1, 4 + x1, 2 + x2} f#_A(x1,x2) = max{1, 4 + x1, 2 + x2} s_A(x1) = max{6, 6 + x1} s#_A(x1) = max{6, 6 + x1} c_A(x1) = max{3, 5 + x1} c#_A(x1) = max{3, 5 + x1} precedence: c > f > s