YES # parallel critical pair closing system (Shintani and Hirokawa 2022) Consider the left-linear TRS R: +(0(),x) -> x +(s(x),y) -> s(+(x,y)) 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.