theorem eximi {x: nat} (a b: wff x): $ a -> b $ > $ E. x a -> E. x b $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
exim |
A. x (a -> b) -> E. x a -> E. x b |
| 2 |
|
hyp h |
a -> b |
| 3 |
2 |
ax_gen |
A. x (a -> b) |
| 4 |
1, 3 |
ax_mp |
E. x a -> E. x b |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp),
axs_pred_calc
(ax_gen,
ax_4)