YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: +(0(),y) -> y +(s(0()),y) -> s(y) s(s(x)) -> x CP(R): s(___y17) -> s(___y17) critical-pair-closing system C: CR(C): see below. ---- CR(R) ---- R is empty.