Theorem bian1 | index | src |

theorem bian1 (a b: wff): $ a -> (a /\ b <-> b) $;
StepHypRefExpression
1 bian1a
(b -> a) -> (a /\ b <-> b)
2 ax_1
a -> b -> a
3 1, 2 syl
a -> (a /\ b <-> b)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)