YES # parallel critical pair closing system (Shintani and Hirokawa 2022) Consider the left-linear TRS R: +(0(),y) -> y +(s(0()),y) -> s(y) +(s(s(x)),y) -> s(s(+(y,x))) Let C be the following subset of R: (empty) The TRS R is left-linear and all parallel critical pairs are joinable by C. Therefore, the confluence of R follows from that of C. # emptiness The empty TRS is confluent.