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.
tp2(y, cons(x', y')) = tp2(x', z') <= get(z') = tp2(y, y'):
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.
Some critical pairs are not trivial and ConCon could not decide whether those all are infeasible.
tp2(y, cons(x', y')) = tp2(x', z') <= get(z') = tp2(y, y'):
For all conditions c 'tcap(c.lhs)' is unifiable with c.rhs.