YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: f(0(),0()) -> f(0(),1()) f(1(),0()) -> f(0(),0()) f(x,y) -> f(y,x) CP(R): f(0(),1()) -> f(0(),0()) f(0(),0()) -> f(0(),1()) f(0(),0()) -> f(0(),1()) f(0(),1()) -> f(0(),0()) critical-pair-closing system C: f(0(),0()) -> f(0(),1()) f(x,y) -> f(y,x) CR(C): see below. ---- CR(R) ---- R : linear and strongly closed [Huet, 1980] R: f(0(),0()) -> f(0(),1()) f(x,y) -> f(y,x) CP(R): f(0(),1()) -> f(0(),0()) f(0(),0()) -> f(0(),1())