Theorem imeq2i | index | src |

theorem imeq2i (a b c: wff): $ b <-> c $ > $ a -> b <-> a -> c $;
StepHypRefExpression
1 id
(b <-> c) -> (b <-> c)
2 1 imeq2d
(b <-> c) -> (a -> b <-> a -> c)
3 hyp h
b <-> c
4 2, 3 ax_mp
a -> b <-> a -> c

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)