Theorem biexan2i ≪ | index | src | ≫

theorem biexan2i (a: wff) {x: nat} (b c: wff x):
  $ b <-> E. x c $ >
  $ a /\ b <-> E. x (a /\ c) $;

Step	Hyp	Ref	Expression
1		hyp h	b <-> E. x c
2	1	a1i	a -> (b <-> E. x c)
3	2	biexan2a	a /\ b <-> E. x (a /\ c)

Axiom use

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