Theorem sylan ≪ | index | src | ≫

theorem sylan (a b c d: wff):
  $ b /\ c -> d $ >
  $ a -> b $ >
  $ a -> c $ >
  $ a -> d $;

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

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)