Theorem ocasepeq1 ≪ | index | src | ≫ 

theorem ocasepeq1 (_z1 _z2: wff) (S: set):
  $ (_z1 <-> _z2) -> ocasep _z1 S == ocasep _z2 S $;
StepHypRefExpression
1 id 
(_z1 <-> _z2) -> (_z1 <-> _z2)
2 1 ocasepeq1d 
(_z1 <-> _z2) -> ocasep _z1 S == ocasep _z2 S

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp, itru), axs_pred_calc (ax_gen, ax_4, ax_5, ax_6, ax_7, ax_10, ax_11, ax_12), axs_set (elab, ax_8)