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.
pair($4, cons($8, $7)) = pair(cons($8, y), $3) <= split($5, x) = pair(y, $3), le($5, $8) = false, split($5, x) = pair($4, $7), le($5, $8) = true:
For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.