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