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