theorem ifpeq3 (p a _b1 _b2: wff):
$ (_b1 <-> _b2) -> (ifp p a _b1 <-> ifp p a _b2) $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
id |
(_b1 <-> _b2) -> (_b1 <-> _b2) |
| 2 |
1 |
ifpeq3d |
(_b1 <-> _b2) -> (ifp p a _b1 <-> ifp p a _b2) |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp)