Theorem bicom | index | src |

theorem bicom (a b: wff): $ (a <-> b) -> (b <-> a) $;
StepHypRefExpression
1 bi2
(a <-> b) -> b -> a
2 bi1
(a <-> b) -> a -> b
3 1, 2 ibid
(a <-> b) -> (b <-> a)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)