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