added proof reconstructon for Z3,
added certificates for simpler re-checking of proofs (no need to invoke external solvers),
added examples and certificates for all examples,
removed Unsynchronized.ref (in smt_normalize.ML)
(benchmark Isabelle
:extrasorts ( T1)
:extrapreds (
(up_1)
(up_2)
(up_3)
)
:assumption (not (implies (or (and up_1 up_2) up_3) (or (implies up_1 (or (and up_3 up_2) (and up_1 up_3))) up_1)))
:formula true
)