Adds PCP theorem paper to references.
Major rewrite to clarify the purpose of the work.
Cuts out a huge chunk of the paper; not enlightening.
Makes theorem more specific.
Updates to correct version of paper containing PCP Theorem.
Notes P = PCP[o(log n), o(log n)].
Noted that adapting a certain proof fails; adds PCP in NNC theorem.
Shows that polynomial time fully explicit expanders are equivalent to NC mildly explicit ones.