Proof of Theorem opkthg
Step | Hyp | Ref
| Expression |
1 | | simp1 955 |
. . . . 5
⊢ ((A ∈ V ∧ B ∈ W ∧ D ∈ T) → A
∈ V) |
2 | | opkth1g 4131 |
. . . . 5
⊢ ((A ∈ V ∧
⟪A, B⟫ = ⟪C, D⟫)
→ A = C) |
3 | 1, 2 | sylan 457 |
. . . 4
⊢ (((A ∈ V ∧ B ∈ W ∧ D ∈ T) ∧
⟪A, B⟫ = ⟪C, D⟫)
→ A = C) |
4 | | simp2 956 |
. . . . . 6
⊢ ((A ∈ V ∧ B ∈ W ∧ D ∈ T) → B
∈ W) |
5 | | simp3 957 |
. . . . . 6
⊢ ((A ∈ V ∧ B ∈ W ∧ D ∈ T) → D
∈ T) |
6 | 4, 5 | jca 518 |
. . . . 5
⊢ ((A ∈ V ∧ B ∈ W ∧ D ∈ T) → (B
∈ W ∧ D ∈ T)) |
7 | | opkeq1 4060 |
. . . . . . . . . . 11
⊢ (A = C →
⟪A, B⟫ = ⟪C, B⟫) |
8 | 7 | eqeq1d 2361 |
. . . . . . . . . 10
⊢ (A = C →
(⟪A, B⟫ = ⟪C, D⟫
↔ ⟪C, B⟫ = ⟪C, D⟫)) |
9 | 8 | biimpd 198 |
. . . . . . . . 9
⊢ (A = C →
(⟪A, B⟫ = ⟪C, D⟫
→ ⟪C, B⟫ = ⟪C, D⟫)) |
10 | 9 | impcom 419 |
. . . . . . . 8
⊢ ((⟪A, B⟫ =
⟪C, D⟫ ∧
A = C)
→ ⟪C, B⟫ = ⟪C, D⟫) |
11 | | df-opk 4059 |
. . . . . . . . . . 11
⊢ ⟪C, B⟫ =
{{C}, {C, B}} |
12 | | df-opk 4059 |
. . . . . . . . . . 11
⊢ ⟪C, D⟫ =
{{C}, {C, D}} |
13 | 11, 12 | eqeq12i 2366 |
. . . . . . . . . 10
⊢ (⟪C, B⟫ =
⟪C, D⟫ ↔ {{C}, {C, B}} = {{C},
{C, D}}) |
14 | | prex 4113 |
. . . . . . . . . . 11
⊢ {C, B} ∈ V |
15 | | prex 4113 |
. . . . . . . . . . 11
⊢ {C, D} ∈ V |
16 | 14, 15 | preqr2 4126 |
. . . . . . . . . 10
⊢ ({{C}, {C, B}} = {{C},
{C, D}}
→ {C, B} = {C,
D}) |
17 | 13, 16 | sylbi 187 |
. . . . . . . . 9
⊢ (⟪C, B⟫ =
⟪C, D⟫ → {C, B} =
{C, D}) |
18 | | preqr2g 4127 |
. . . . . . . . 9
⊢ ((B ∈ W ∧ D ∈ T) → ({C,
B} = {C, D} →
B = D)) |
19 | 17, 18 | syl5 28 |
. . . . . . . 8
⊢ ((B ∈ W ∧ D ∈ T) → (⟪C, B⟫ =
⟪C, D⟫ → B = D)) |
20 | 10, 19 | syl5 28 |
. . . . . . 7
⊢ ((B ∈ W ∧ D ∈ T) → ((⟪A, B⟫ =
⟪C, D⟫ ∧
A = C)
→ B = D)) |
21 | 20 | exp3a 425 |
. . . . . 6
⊢ ((B ∈ W ∧ D ∈ T) → (⟪A, B⟫ =
⟪C, D⟫ → (A = C →
B = D))) |
22 | 21 | imp 418 |
. . . . 5
⊢ (((B ∈ W ∧ D ∈ T) ∧
⟪A, B⟫ = ⟪C, D⟫)
→ (A = C → B =
D)) |
23 | 6, 22 | sylan 457 |
. . . 4
⊢ (((A ∈ V ∧ B ∈ W ∧ D ∈ T) ∧
⟪A, B⟫ = ⟪C, D⟫)
→ (A = C → B =
D)) |
24 | 3, 23 | jcai 522 |
. . 3
⊢ (((A ∈ V ∧ B ∈ W ∧ D ∈ T) ∧
⟪A, B⟫ = ⟪C, D⟫)
→ (A = C ∧ B = D)) |
25 | 24 | ex 423 |
. 2
⊢ ((A ∈ V ∧ B ∈ W ∧ D ∈ T) → (⟪A, B⟫ =
⟪C, D⟫ → (A = C ∧ B = D))) |
26 | | opkeq12 4062 |
. 2
⊢ ((A = C ∧ B = D) → ⟪A, B⟫ =
⟪C, D⟫) |
27 | 25, 26 | impbid1 194 |
1
⊢ ((A ∈ V ∧ B ∈ W ∧ D ∈ T) → (⟪A, B⟫ =
⟪C, D⟫ ↔ (A = C ∧ B = D))) |