YES ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: nats() -> :(0(),inc(nats())) inc(:(x,y)) -> :(s(x),inc(y)) inc(tl(nats())) -> tl(inc(nats())) hd(:(x,y)) -> x tl(:(x,y)) -> y d(:(x,y)) -> :(x,:(x,d(y))) CP(R): inc(tl(:(0(),inc(nats())))) -> tl(inc(nats())) critical-pair-closing system C: nats() -> :(0(),inc(nats())) inc(:(x,y)) -> :(s(x),inc(y)) tl(:(x,y)) -> y CR(C): see below. ---- CR(R) ---- R : left-linear, C : CR and CP-closing, and Cdup/R : SN R: nats() -> :(0(),inc(nats())) inc(:(x,y)) -> :(s(x),inc(y)) tl(:(x,y)) -> y CP(R): critical-pair-closing system C: CR(C): see below. ---- CR(R) ---- R is empty.