YES Problem: F(c(x)) -> G(x) G(x) -> F(x) c(x) -> x Proof: Church Rosser Transformation Processor: strict: F(c(x)) -> G(x) G(x) -> F(x) c(x) -> x weak: critical peaks: 1 F(x) <-2|0[]- F(c(x)) -0|[]-> G(x) Closedness Processor (*strongly -- <=7 steps*): strict: weak: Qed