theorem pi21pr (a b c: nat): $ pi21 (a, b, c) = b $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
eqtr |
pi21 (a, b, c) = fst (b, c) -> fst (b, c) = b -> pi21 (a, b, c) = b |
| 2 |
|
fsteq |
snd (a, b, c) = b, c -> fst (snd (a, b, c)) = fst (b, c) |
| 3 |
2 |
conv pi21 |
snd (a, b, c) = b, c -> pi21 (a, b, c) = fst (b, c) |
| 4 |
|
sndpr |
snd (a, b, c) = b, c |
| 5 |
3, 4 |
ax_mp |
pi21 (a, b, c) = fst (b, c) |
| 6 |
1, 5 |
ax_mp |
fst (b, c) = b -> pi21 (a, b, c) = b |
| 7 |
|
fstpr |
fst (b, c) = b |
| 8 |
6, 7 |
ax_mp |
pi21 (a, b, c) = b |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp,
itru),
axs_pred_calc
(ax_gen,
ax_4,
ax_5,
ax_6,
ax_7,
ax_10,
ax_11,
ax_12),
axs_set
(elab,
ax_8),
axs_the
(theid,
the0),
axs_peano
(peano1,
peano2,
peano5,
addeq,
muleq,
add0,
addS,
mul0,
mulS)