Theorem syl5bbr | index | src |

theorem syl5bbr (a b c d: wff):
  $ c <-> b $ >
  $ a -> (c <-> d) $ >
  $ a -> (b <-> d) $;
StepHypRefExpression
1 bicom
(c <-> b) -> (b <-> c)
2 hyp h1
c <-> b
3 1, 2 ax_mp
b <-> c
4 hyp h2
a -> (c <-> d)
5 3, 4 syl5bb
a -> (b <-> d)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)