MAYBE Proof: ConCon could not decide confluence of the system. \cite{SMI95}, Corollary 4.7 or 5.3 do not apply. Some critical pairs are not trivial and ConCon could not decide whether those all are infeasible. pout(g(x)) = pout(f(y)) <= pin(x) = pout(g(y)): For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.