YES # strong closedness (Huet 1980) Consider the left-linear TRS R: 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)) R is linear and every critical pair is strongly closed