(VAR x) (RULES a(b(x)) -> a(c(x)) c(c(x)) -> c(b(x)) c(c(x)) -> c(c(x)) a(c(x)) -> c(b(x)) b(c(x)) -> a(c(x)) c(c(x)) -> c(c(x)) c(b(x)) -> a(b(x)) ) (COMMENT submitted by: Johannes Waldmann )