Theorem rexeqd ≪ | index | src | ≫

theorem rexeqd (G: wff) {x: nat} (p a b: wff x):
  $ G -> (a <-> b) $ >
  $ G -> (E. x (p /\ a) <-> E. x (p /\ b)) $;

Step	Hyp	Ref	Expression
1		hyp h	G -> (a <-> b)
2	1	aneq2d	G -> (p /\ a <-> p /\ b)
3	2	exeqd	G -> (E. x (p /\ a) <-> E. x (p /\ b))

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp), axs_pred_calc (ax_gen, ax_4, ax_5)