theorem nfal1 {x: nat} (a: wff x): $ F/ x A. x a $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
alex |
A. x a <-> ~E. x ~a |
| 2 |
|
nfex1 |
F/ x E. x ~a |
| 3 |
2 |
nfnot |
F/ x ~E. x ~a |
| 4 |
1, 3 |
nfx |
F/ x A. x a |
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_12)