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. lte(x, y) = tt <= lte(s(x), y) = tt: For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.