NO Problem: H(F(x,y)) -> F(H(R(x)),y) F(x,K(y,z)) -> G(P(y),Q(z,x)) H(Q(x,y)) -> Q(x,H(R(y))) Q(x,H(R(y))) -> H(Q(x,y)) H(G(x,y)) -> G(x,H(y)) Proof: Matrix Interpretation Processor: dimension: 1 interpretation: [G](x0, x1) = 3x0 + 4x1 + 1, [Q](x0, x1) = 2x0 + x1, [P](x0) = 2x0, [K](x0, x1) = 4x0 + 2x1 + 4, [R](x0) = x0, [H](x0) = x0, [F](x0, x1) = 4x0 + 4x1 + 1 orientation: H(F(x,y)) = 4x + 4y + 1 >= 4x + 4y + 1 = F(H(R(x)),y) F(x,K(y,z)) = 4x + 16y + 8z + 17 >= 4x + 6y + 8z + 1 = G(P(y),Q(z,x)) H(Q(x,y)) = 2x + y >= 2x + y = Q(x,H(R(y))) Q(x,H(R(y))) = 2x + y >= 2x + y = H(Q(x,y)) H(G(x,y)) = 3x + 4y + 1 >= 3x + 4y + 1 = G(x,H(y)) problem: H(F(x,y)) -> F(H(R(x)),y) H(Q(x,y)) -> Q(x,H(R(y))) Q(x,H(R(y))) -> H(Q(x,y)) H(G(x,y)) -> G(x,H(y)) Unfolding Processor: loop length: 2 terms: H(Q(x31,x32)) Q(x31,H(R(x32))) context: [] substitution: x31 -> x31 x32 -> x32 Qed