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. process(app(map_f(self, nil), sndsplit(z, x')), z) = process(sndsplit(z, app(map_f(self, nil), x')), z) <= leq(z, length(x')) = false, empty(fstsplit(z, app(map_f(self, nil), x'))) = false, leq(z, length(x')) = true, empty(fstsplit(z, x')) = false: For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.