Theorem funceq1 ≪ | index | src | ≫ 

theorem funceq1 (_F1 _F2 A B: set):
  $ _F1 == _F2 -> (func _F1 A B <-> func _F2 A B) $;
StepHypRefExpression
1 id 
_F1 == _F2 -> _F1 == _F2
2 1 funceq1d 
_F1 == _F2 -> (func _F1 A B <-> func _F2 A B)

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)