theorem ifpeq2 (p _a1 _a2 b: wff):
$ (_a1 <-> _a2) -> (ifp p _a1 b <-> ifp p _a2 b) $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
id |
(_a1 <-> _a2) -> (_a1 <-> _a2) |
| 2 |
1 |
ifpeq2d |
(_a1 <-> _a2) -> (ifp p _a1 b <-> ifp p _a2 b) |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp)