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. lte(0, x) = T <= lte(0, p(x)) = T: For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs. \cite{GNG13}, Theorem 9 does not apply. \cite{SMI95}, Corollary 4.7 or 5.3 do not apply.