theorem eqss (A B: set): $ A == B -> A C_ B $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
ssid |
A C_ A |
| 2 |
|
sseq2 |
A == B -> (A C_ A <-> A C_ B) |
| 3 |
1, 2 |
mpbii |
A == B -> A C_ B |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp),
axs_pred_calc
(ax_gen,
ax_4,
ax_5,
ax_6,
ax_7,
ax_10,
ax_12),
axs_set
(ax_8)