Theorem com12 ≪ | index | src | ≫

theorem com12 (a b c: wff): $ a -> b -> c $ > $ b -> a -> c $;

Step	Hyp	Ref	Expression
1		hyp h	a -> b -> c
2	1	a2i	(a -> b) -> a -> c
3		ax_1	b -> a -> b
4	2, 3	syl	b -> a -> c

Axiom use

axs_prop_calc (ax_1, ax_2, ax_mp)