theorem subid (a: nat): $ a - a = 0 $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
eqsub1 |
0 + a = a -> a - a = 0 |
| 2 |
|
add01 |
0 + a = a |
| 3 |
1, 2 |
ax_mp |
a - a = 0 |
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),
axs_peano
(peano2,
peano5,
addeq,
add0,
addS)