theorem ibida (a b c: wff):
$ a /\ b -> c $ >
$ a /\ c -> b $ >
$ a -> (b <-> c) $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
hyp h1 |
a /\ b -> c |
| 2 |
1 |
exp |
a -> b -> c |
| 3 |
|
hyp h2 |
a /\ c -> b |
| 4 |
3 |
exp |
a -> c -> b |
| 5 |
2, 4 |
ibid |
a -> (b <-> c) |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp)