YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: f(f(f(b()))) -> b() h(h(a(),a()),h(f(f(a())),h(c(),b()))) -> f(c()) CP(R): critical-pair-closing system C: f(f(f(b()))) -> b() CR(C): see below. ---- CR(R) ---- R : linear and strongly closed [Huet, 1980] R: f(f(f(b()))) -> b() CP(R):