Theorem sseq2d | index | src |

theorem sseq2d (_G: wff) (A _B1 _B2: set):
  $ _G -> _B1 == _B2 $ >
  $ _G -> (A C_ _B1 <-> A C_ _B2) $;
StepHypRefExpression
1 eqsidd
_G -> A == A
2 hyp _h
_G -> _B1 == _B2
3 1, 2 sseqd
_G -> (A C_ _B1 <-> A C_ _B2)

Axiom use

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