src/HOL/SMT/Examples/cert/z3_prop_05

slightly leaner and more direct control of worker activity etc.;

(benchmark Isabelle
:extrasorts ( T1)
:extrapreds (
  (up_1)
  (up_2)
  (up_3)
  (up_4)
 )
:assumption (or (and up_1 up_2) (and up_3 up_4))
:assumption (not (or (and up_1 up_2) (and up_3 up_4)))
:formula true
)