Theorem sylibr ≪ | index | src | ≫

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

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

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)