YES # Parallel rule labeling (Zankl et al. 2015). Consider the left-linear TRS R: +(x,0()) -> x +(x,s(y)) -> s(+(x,y)) +(0(),y) -> y +(s(x),y) -> s(+(x,y)) *(x,0()) -> 0() *(x,s(y)) -> +(*(x,y),x) *(0(),y) -> 0() *(s(x),y) -> +(*(x,y),y) +(+(x,y),z) -> +(x,+(y,z)) +(x,y) -> +(y,x) All parallel critical peaks (except C's) are decreasing wrt rule labeling: phi(+(x,0()) -> x) = 2 phi(+(x,s(y)) -> s(+(x,y))) = 4 phi(+(0(),y) -> y) = 1 phi(+(s(x),y) -> s(+(x,y))) = 4 phi(*(x,0()) -> 0()) = 3 phi(*(x,s(y)) -> +(*(x,y),x)) = 9 phi(*(0(),y) -> 0()) = 3 phi(*(s(x),y) -> +(*(x,y),y)) = 9 phi(+(+(x,y),z) -> +(x,+(y,z))) = 7 phi(+(x,y) -> +(y,x)) = 7 psi(+(x,0()) -> x) = 4 psi(+(x,s(y)) -> s(+(x,y))) = 8 psi(+(0(),y) -> y) = 5 psi(+(s(x),y) -> s(+(x,y))) = 3 psi(*(x,0()) -> 0()) = 6 psi(*(x,s(y)) -> +(*(x,y),x)) = 10 psi(*(0(),y) -> 0()) = 6 psi(*(s(x),y) -> +(*(x,y),y)) = 10 psi(+(+(x,y),z) -> +(x,+(y,z))) = 6 psi(+(x,y) -> +(y,x)) = 3