YES # Compositional parallel rule labeling (Shintani and Hirokawa 2022). Consider the left-linear TRS R: f(0(),0()) -> f(0(),1()) f(1(),0()) -> f(0(),0()) f(x,y) -> f(y,x) Let C be the following subset of R: (empty) All parallel critical peaks (except C's) are decreasing wrt rule labeling: phi(f(0(),0()) -> f(0(),1())) = 5 phi(f(1(),0()) -> f(0(),0())) = 5 phi(f(x,y) -> f(y,x)) = 4 psi(f(0(),0()) -> f(0(),1())) = 1 psi(f(1(),0()) -> f(0(),0())) = 3 psi(f(x,y) -> f(y,x)) = 2 Therefore, the confluence of R follows from that of C. # Compositional parallel critical pair system (Shintani and Hirokawa 2022). Consider the left-linear TRS R: (empty) Let C be the following subset of R: (empty) The parallel critical pair system PCPS(R,C) is: (empty) All pairs in PCP(R) are joinable and PCPS(R,C)/R is terminating. Therefore, the confluence of R follows from that of C. # emptiness The empty TRS is confluent.