YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: -(+(x,y)) -> +(-(x),-(y)) +(-(x),-(y)) -> -(+(x,y)) CP(R): +(+(-(___y5),-(___y6)),-(___y8)) -> -(+(+(___y5,___y6),___y8)) +(-(___y7),+(-(___y5),-(___y6))) -> -(+(___y7,+(___y5,___y6))) -(-(+(___y9,___y10))) -> +(-(-(___y9)),-(-(___y10))) critical-pair-closing system C: -(+(x,y)) -> +(-(x),-(y)) CR(C): see below. ---- CR(R) ---- R : linear and strongly closed [Huet, 1980] R: -(+(x,y)) -> +(-(x),-(y)) CP(R):