theorem oreq2i (a b c: wff): $ b <-> c $ > $ a \/ b <-> a \/ c $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
id |
(b <-> c) -> (b <-> c) |
| 2 |
1 |
oreq2d |
(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)