Q. Proof that 3UNIT is P-complete:

	(a) Work out the details of the proof that
	3UNIT is in P (the CLAIM was only sketched).

	(b) We only showed that 4UNIT is P-hard.
	Show that 3UNIT is P-hard. 

Q.  Explicitly describe a specific encoding such that for each
        binary string <var>x<var>, there is a corresponding
        deterministic 1-tape TM's that uses {0,1} as input
        alphabet.  This gives rise to a list
                <var>M_0, M_1<var>, etc
        You must explicitly address the following issues:

        (1) some strings may not encode a proper TM of the above specs
        (2) the TM's may use ANY tape alphabet in \Sigma_\infty
                and ANY set of states in Q_\infty
        (3) the efficient recurrence property holds: