Theorem syld | index | src |

theorem syld (a b c d: wff):
  $ a -> b -> c $ >
  $ a -> c -> d $ >
  $ a -> b -> d $;
StepHypRefExpression
1 hyp h1
a -> b -> c
2 hyp h2
a -> c -> d
3 2 a1d
a -> b -> c -> d
4 3 a2d
a -> (b -> c) -> b -> d
5 1, 4 mpd
a -> b -> d

Axiom use

axs_prop_calc (ax_1, ax_2, ax_mp)