YES TRS: U11(tt(),M,N) -> U12(tt(),activate(M),activate(N)) U12(tt(),M,N) -> s(plus(activate(N),activate(M))) plus(N,0()) -> N plus(N,s(M)) -> U11(tt(),M,N) activate(X) -> X linear polynomial interpretations on N: U11_A(x1,x2,x3) = x2 + x3 + 3 U11#_A(x1,x2,x3) = x2 + 3 tt_A = 1 tt#_A = 0 U12_A(x1,x2,x3) = x1 + x2 + x3 + 2 U12#_A(x1,x2,x3) = x2 + 2 activate_A(x1) = x1 activate#_A(x1) = 0 s_A(x1) = x1 + 3 s#_A(x1) = 1 plus_A(x1,x2) = x1 + x2 plus#_A(x1,x2) = x2 + 1 0_A = 1 0#_A = 0 precedence: plus > U11 = 0 > U12 > activate = s > tt