Proof of Theorem shscomt
| Step | Hyp | Ref
| Expression |
| 1 | | shelt 5118 |
. . . . . . . . 9
⊢ ((A
∈ Sℋ ∧ y
∈ A) → y ∈ ℋ ) |
| 2 | | shelt 5118 |
. . . . . . . . 9
⊢ ((B
∈ Sℋ ∧ z
∈ B) → z ∈ ℋ ) |
| 3 | 1, 2 | anim12i 268 |
. . . . . . . 8
⊢ (((A
∈ Sℋ ∧ y
∈ A) ∧ (B ∈ Sℋ ∧ z ∈ B))
→ (y ∈ ℋ ∧ z ∈ ℋ )) |
| 4 | 3 | an4s 390 |
. . . . . . 7
⊢ (((A
∈ Sℋ ∧ B
∈ Sℋ ) ∧ (y ∈ A ∧
z ∈ B)) → (y
∈ ℋ ∧ z ∈ ℋ
)) |
| 5 | | ax-hvcom 4985 |
. . . . . . 7
⊢ ((y
∈ ℋ ∧ z ∈ ℋ )
→ (y +v z) = (z
+v y)) |
| 6 | 4, 5 | syl 12 |
. . . . . 6
⊢ (((A
∈ Sℋ ∧ B
∈ Sℋ ) ∧ (y ∈ A ∧
z ∈ B)) → (y
+v z) = (z +v y)) |
| 7 | 6 | cleq2d 1112 |
. . . . 5
⊢ (((A
∈ Sℋ ∧ B
∈ Sℋ ) ∧ (y ∈ A ∧
z ∈ B)) → (x =
(y +v z) ↔ x =
(z +v y))) |
| 8 | 7 | bi2rexdva 1234 |
. . . 4
⊢ ((A
∈ Sℋ ∧ B
∈ Sℋ ) → (∃y ∈ A
∃z ∈ B x = (y +v z) ↔ ∃y ∈ A
∃z ∈ B x = (z +v y))) |
| 9 | | rexcom 1313 |
. . . 4
⊢ (∃y ∈ A
∃z ∈ B x = (z +v y) ↔ ∃z ∈ B
∃y ∈ A x = (z +v y)) |
| 10 | 8, 9 | syl6bb 414 |
. . 3
⊢ ((A
∈ Sℋ ∧ B
∈ Sℋ ) → (∃y ∈ A
∃z ∈ B x = (y +v z) ↔ ∃z ∈ B
∃y ∈ A x = (z +v y))) |
| 11 | | shselt 5280 |
. . 3
⊢ ((A
∈ Sℋ ∧ B
∈ Sℋ ) → (x ∈ (A
+ℋ B) ↔
∃y ∈ A ∃z
∈ B x = (y
+v z))) |
| 12 | | shselt 5280 |
. . . 4
⊢ ((B
∈ Sℋ ∧ A
∈ Sℋ ) → (x ∈ (B
+ℋ A) ↔
∃z ∈ B ∃y
∈ A x = (z
+v y))) |
| 13 | 12 | ancoms 334 |
. . 3
⊢ ((A
∈ Sℋ ∧ B
∈ Sℋ ) → (x ∈ (B
+ℋ A) ↔
∃z ∈ B ∃y
∈ A x = (z
+v y))) |
| 14 | 10, 11, 13 | 3bitr4d 424 |
. 2
⊢ ((A
∈ Sℋ ∧ B
∈ Sℋ ) → (x ∈ (A
+ℋ B) ↔ x ∈ (B
+ℋ A))) |
| 15 | 14 | cleqrd 1100 |
1
⊢ ((A
∈ Sℋ ∧ B
∈ Sℋ ) → (A +ℋ B) = (B
+ℋ A)) |