YES # Parallel rule labeling (Zankl et al. 2015). Consider the left-linear TRS R: c() -> b() a() -> a() b() -> b() f(f(a())) -> c() All parallel critical peaks (except C's) are decreasing wrt rule labeling: phi(c() -> b()) = 1 phi(a() -> a()) = 1 phi(b() -> b()) = 1 phi(f(f(a())) -> c()) = 1 psi(c() -> b()) = 1 psi(a() -> a()) = 1 psi(b() -> b()) = 1 psi(f(f(a())) -> c()) = 1