theorem unieqd (_G: wff) (_A1 _A2: set):
$ _G -> _A1 == _A2 $ >
$ _G -> sUnion _A1 == sUnion _A2 $;
Step | Hyp | Ref | Expression |
1 |
|
biidd |
_G -> (x e. y <-> x e. y) |
2 |
|
eqidd |
_G -> y = y |
3 |
|
hyp _Ah |
_G -> _A1 == _A2 |
4 |
2, 3 |
eleqd |
_G -> (y e. _A1 <-> y e. _A2) |
5 |
1, 4 |
aneqd |
_G -> (x e. y /\ y e. _A1 <-> x e. y /\ y e. _A2) |
6 |
5 |
exeqd |
_G -> (E. y (x e. y /\ y e. _A1) <-> E. y (x e. y /\ y e. _A2)) |
7 |
6 |
abeqd |
_G -> {x | E. y (x e. y /\ y e. _A1)} == {x | E. y (x e. y /\ y e. _A2)} |
8 |
7 |
conv sUnion |
_G -> sUnion _A1 == sUnion _A2 |
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)