YES

# Parallel rule labeling (Zankl et al. 2015).

Consider the left-linear TRS R:

  or(true(),true()) -> true()
  or(x,y) -> or(y,x)

All parallel critical peaks (except C's) are decreasing wrt rule labeling:

  phi(or(true(),true()) -> true()) = 1
  phi(or(x,y) -> or(y,x)) = 1

  psi(or(true(),true()) -> true()) = 1
  psi(or(x,y) -> or(y,x)) = 1