theorem oreq1d (_G _a1 _a2 b: wff):
$ _G -> (_a1 <-> _a2) $ >
$ _G -> (_a1 \/ b <-> _a2 \/ b) $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
hyp _h |
_G -> (_a1 <-> _a2) |
| 2 |
|
biidd |
_G -> (b <-> b) |
| 3 |
1, 2 |
oreqd |
_G -> (_a1 \/ b <-> _a2 \/ b) |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp)