Theorem sylibrd | index | src |

theorem sylibrd (a b c d: wff):
  $ a -> b -> c $ >
  $ a -> (d <-> c) $ >
  $ a -> b -> d $;
StepHypRefExpression
1 hyp h1
a -> b -> c
2 hyp h2
a -> (d <-> c)
3 2 bi2d
a -> c -> d
4 1, 3 syld
a -> b -> d

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)