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