Theorem writeeq1 ≪ | index | src | ≫ 

theorem writeeq1 (_F1 _F2: set) (a b: nat):
  $ _F1 == _F2 -> write _F1 a b == write _F2 a b $;
StepHypRefExpression
1 id 
_F1 == _F2 -> _F1 == _F2
2 1 writeeq1d 
_F1 == _F2 -> write _F1 a b == write _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)