Theorem bieq2 | index | src |

theorem bieq2 (a b c: wff): $ (b <-> c) -> (a <-> b <-> (a <-> c)) $;
StepHypRefExpression
1 id
(b <-> c) -> (b <-> c)
2 1 bieq2d
(b <-> c) -> (a <-> b <-> (a <-> c))

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)