YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: f(a()) -> b() f(a()) -> f(c()) a() -> d() f(d()) -> b() f(c()) -> b() d() -> c() CP(R): b() -> f(c()) f(c()) -> b() f(d()) -> b() f(d()) -> f(c()) f(c()) -> b() critical-pair-closing system C: f(d()) -> b() f(c()) -> b() CR(C): see below. ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: f(d()) -> b() f(c()) -> b() CP(R): critical-pair-closing system C: CR(C): see below. ---- CR(R) ---- R is empty.