MAYBE Problem: c(b(x)) -> a(c(x)) b(a(x)) -> c(c(x)) b(c(x)) -> c(a(x)) c(c(x)) -> a(b(x)) b(c(x)) -> a(c(x)) c(a(x)) -> b(c(x)) b(b(x)) -> c(a(x)) a(a(x)) -> a(b(x)) Proof: Open