Proof of Theorem occont
| Step | Hyp | Ref
| Expression |
| 1 | | ssel 1502 |
. . . . . . . . . 10
⊢ (A
⊆ B → (y ∈ A
→ y ∈ B)) |
| 2 | 1 | syl4d 28 |
. . . . . . . . 9
⊢ (A
⊆ B → ((y ∈ B
→ (x
·i y) = 0)
→ (y ∈ A → (x
·i y) =
0))) |
| 3 | 2 | 19.20dv 946 |
. . . . . . . 8
⊢ (A
⊆ B → (∀y(y ∈
B → (x ·i y) = 0) → ∀y(y ∈
A → (x ·i y) = 0))) |
| 4 | | df-ral 1205 |
. . . . . . . 8
⊢ (∀y ∈ B
(x ·i
y) = 0 ↔ ∀y(y ∈
B → (x ·i y) = 0)) |
| 5 | | df-ral 1205 |
. . . . . . . 8
⊢ (∀y ∈ A
(x ·i
y) = 0 ↔ ∀y(y ∈
A → (x ·i y) = 0)) |
| 6 | 3, 4, 5 | 3imtr4g 426 |
. . . . . . 7
⊢ (A
⊆ B → (∀y ∈ B
(x ·i
y) = 0 → ∀y ∈ A
(x ·i
y) = 0)) |
| 7 | 6 | a1d 14 |
. . . . . 6
⊢ (A
⊆ B → (x ∈ ℋ → (∀y ∈ B
(x ·i
y) = 0 → ∀y ∈ A
(x ·i
y) = 0))) |
| 8 | 7 | r19.21aiv 1259 |
. . . . 5
⊢ (A
⊆ B → ∀x ∈ ℋ (∀y ∈ B
(x ·i
y) = 0 → ∀y ∈ A
(x ·i
y) = 0)) |
| 9 | | ss2rab 1553 |
. . . . 5
⊢ ({x
∈ ℋ ∣∀y ∈
B (x
·i y) = 0}
⊆ {x ∈ ℋ
∣∀y ∈ A (x
·i y) = 0}
↔ ∀x ∈ ℋ
(∀y ∈ B (x
·i y) = 0
→ ∀y ∈ A (x
·i y) =
0)) |
| 10 | 8, 9 | sylibr 175 |
. . . 4
⊢ (A
⊆ B → {x ∈ ℋ ∣∀y ∈ B
(x ·i
y) = 0} ⊆ {x ∈ ℋ ∣∀y ∈ A
(x ·i
y) = 0}) |
| 11 | 10 | adantl 305 |
. . 3
⊢ (((A
⊆ ℋ ∧ B ⊆ ℋ )
∧ A ⊆ B) → {x
∈ ℋ ∣∀y ∈
B (x
·i y) = 0}
⊆ {x ∈ ℋ
∣∀y ∈ A (x
·i y) =
0}) |
| 12 | | ocvalt 5161 |
. . . 4
⊢ (B
⊆ ℋ → (⊥ ‘B) =
{x ∈ ℋ ∣∀y ∈ B
(x ·i
y) = 0}) |
| 13 | 12 | ad2antlr 321 |
. . 3
⊢ (((A
⊆ ℋ ∧ B ⊆ ℋ )
∧ A ⊆ B) → (⊥ ‘B) = {x ∈
ℋ ∣∀y ∈ B (x
·i y) =
0}) |
| 14 | | ocvalt 5161 |
. . . 4
⊢ (A
⊆ ℋ → (⊥ ‘A) =
{x ∈ ℋ ∣∀y ∈ A
(x ·i
y) = 0}) |
| 15 | 14 | ad2antll 320 |
. . 3
⊢ (((A
⊆ ℋ ∧ B ⊆ ℋ )
∧ A ⊆ B) → (⊥ ‘A) = {x ∈
ℋ ∣∀y ∈ A (x
·i y) =
0}) |
| 16 | 11, 13, 15 | 3sstr4d 1543 |
. 2
⊢ (((A
⊆ ℋ ∧ B ⊆ ℋ )
∧ A ⊆ B) → (⊥ ‘B) ⊆ (⊥ ‘A)) |
| 17 | 16 | exp 291 |
1
⊢ ((A
⊆ ℋ ∧ B ⊆ ℋ )
→ (A ⊆ B → (⊥ ‘B) ⊆ (⊥ ‘A))) |