YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: or(true(),true()) -> true() or(x,y) -> or(y,x) CP(R): true() -> or(true(),true()) or(true(),true()) -> true() critical-pair-closing system C: or(true(),true()) -> true() CR(C): see below. ---- CR(R) ---- R : linear and strongly closed [Huet, 1980] R: or(true(),true()) -> true() CP(R):