Theorem bicomb | index | src |

theorem bicomb (a b: wff): $ a <-> b <-> (b <-> a) $;
StepHypRefExpression
1 bicom
(a <-> b) -> (b <-> a)
2 bicom
(b <-> a) -> (a <-> b)
3 1, 2 ibii
a <-> b <-> (b <-> a)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)