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