MAYBE Proof: ConCon could not decide confluence of the system. \cite{ALS94}, Theorem 4.1 does not apply. ConCon could not decide whether all critical pairs are joinable or not. pout(g(x)) = pout(f(y)) <= pin(x) = pout(g(y)): For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.