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.
cons(x', cons(y', z')) = cons(y', insert(z', x')) <= lte(x', y') = false, lte(x', y') = true:
For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.