Theorem mpbir ≪ | index | src | ≫

theorem mpbir (a b: wff): $ b <-> a $ > $ a $ > $ b $;

Step	Hyp	Ref	Expression
1		hyp h1	b <-> a
2	1	bi2i	a -> b
3		hyp h2	a
4	2, 3	ax_mp	b

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)