Theorem sylc ≪ | index | src | ≫

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

Step	Hyp	Ref	Expression
1		hyp h2	a -> c
2		hyp h	b -> c -> d
3		hyp h1	a -> b
4	2, 3	syl	a -> c -> d
5	1, 4	mpd	a -> d

Axiom use

axs_prop_calc (ax_1, ax_2, ax_mp)