Theorem sylbi ≪ | index | src | ≫

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

Step	Hyp	Ref	Expression
1		hyp h2	b -> c
2		hyp h1	a <-> b
3	2	bi1i	a -> b
4	1, 3	syl	a -> c

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)