Proof of Theorem 2sb5ndVD
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | ax6e2ndeq 44579 | . 2
⊢ ((¬
∀𝑥 𝑥 = 𝑦 ∨ 𝑢 = 𝑣) ↔ ∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣)) | 
| 2 |  | anabs5 663 | . . . 4
⊢
((∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) ↔ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 3 |  | 2pm13.193 44572 | . . . . . . . . 9
⊢ (((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ ((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑)) | 
| 4 | 3 | exbii 1848 | . . . . . . . 8
⊢
(∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ ∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑)) | 
| 5 |  | hbs1 2274 | . . . . . . . . . . . . 13
⊢ ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑥[𝑢 / 𝑥][𝑣 / 𝑦]𝜑) | 
| 6 |  | idn1 44594 | . . . . . . . . . . . . . 14
⊢ (   ∀𝑥 𝑥 = 𝑦   ▶   ∀𝑥 𝑥 = 𝑦   ) | 
| 7 |  | axc11 2435 | . . . . . . . . . . . . . 14
⊢
(∀𝑥 𝑥 = 𝑦 → (∀𝑥[𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 8 | 6, 7 | e1a 44647 | . . . . . . . . . . . . 13
⊢ (   ∀𝑥 𝑥 = 𝑦   ▶   (∀𝑥[𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)   ) | 
| 9 |  | imim1 83 | . . . . . . . . . . . . 13
⊢ (([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑥[𝑢 / 𝑥][𝑣 / 𝑦]𝜑) → ((∀𝑥[𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑) → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑))) | 
| 10 | 5, 8, 9 | e01 44711 | . . . . . . . . . . . 12
⊢ (   ∀𝑥 𝑥 = 𝑦   ▶   ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)   ) | 
| 11 | 10 | in1 44591 | . . . . . . . . . . 11
⊢
(∀𝑥 𝑥 = 𝑦 → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 12 |  | hbs1 2274 | . . . . . . . . . . . . . . 15
⊢ ([𝑣 / 𝑦]𝜑 → ∀𝑦[𝑣 / 𝑦]𝜑) | 
| 13 | 12 | sbt 2066 | . . . . . . . . . . . . . 14
⊢ [𝑢 / 𝑥]([𝑣 / 𝑦]𝜑 → ∀𝑦[𝑣 / 𝑦]𝜑) | 
| 14 |  | sbi1 2071 | . . . . . . . . . . . . . 14
⊢ ([𝑢 / 𝑥]([𝑣 / 𝑦]𝜑 → ∀𝑦[𝑣 / 𝑦]𝜑) → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → [𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑)) | 
| 15 | 13, 14 | e0a 44792 | . . . . . . . . . . . . 13
⊢ ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → [𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑) | 
| 16 |  | idn1 44594 | . . . . . . . . . . . . . . 15
⊢ (    ¬ ∀𝑥 𝑥 = 𝑦   ▶    ¬
∀𝑥 𝑥 = 𝑦   ) | 
| 17 |  | axc11n 2431 | . . . . . . . . . . . . . . . 16
⊢
(∀𝑦 𝑦 = 𝑥 → ∀𝑥 𝑥 = 𝑦) | 
| 18 | 17 | con3i 154 | . . . . . . . . . . . . . . 15
⊢ (¬
∀𝑥 𝑥 = 𝑦 → ¬ ∀𝑦 𝑦 = 𝑥) | 
| 19 | 16, 18 | e1a 44647 | . . . . . . . . . . . . . 14
⊢ (    ¬ ∀𝑥 𝑥 = 𝑦   ▶    ¬
∀𝑦 𝑦 = 𝑥   ) | 
| 20 |  | sbal2 2534 | . . . . . . . . . . . . . 14
⊢ (¬
∀𝑦 𝑦 = 𝑥 → ([𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑 ↔ ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 21 | 19, 20 | e1a 44647 | . . . . . . . . . . . . 13
⊢ (    ¬ ∀𝑥 𝑥 = 𝑦   ▶   ([𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑 ↔ ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)   ) | 
| 22 |  | imbi2 348 | . . . . . . . . . . . . . 14
⊢ (([𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑 ↔ ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑) → (([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → [𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑) ↔ ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑))) | 
| 23 | 22 | biimpcd 249 | . . . . . . . . . . . . 13
⊢ (([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → [𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑) → (([𝑢 / 𝑥]∀𝑦[𝑣 / 𝑦]𝜑 ↔ ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑) → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑))) | 
| 24 | 15, 21, 23 | e01 44711 | . . . . . . . . . . . 12
⊢ (    ¬ ∀𝑥 𝑥 = 𝑦   ▶   ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)   ) | 
| 25 | 24 | in1 44591 | . . . . . . . . . . 11
⊢ (¬
∀𝑥 𝑥 = 𝑦 → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 26 | 11, 25 | pm2.61i 182 | . . . . . . . . . 10
⊢ ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 → ∀𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑) | 
| 27 | 26 | nf5i 2146 | . . . . . . . . 9
⊢
Ⅎ𝑦[𝑢 / 𝑥][𝑣 / 𝑦]𝜑 | 
| 28 | 27 | 19.41 2235 | . . . . . . . 8
⊢
(∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ (∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 29 | 4, 28 | bitr3i 277 | . . . . . . 7
⊢
(∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑) ↔ (∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 30 | 29 | exbii 1848 | . . . . . 6
⊢
(∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑) ↔ ∃𝑥(∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 31 | 5 | nf5i 2146 | . . . . . . 7
⊢
Ⅎ𝑥[𝑢 / 𝑥][𝑣 / 𝑦]𝜑 | 
| 32 | 31 | 19.41 2235 | . . . . . 6
⊢
(∃𝑥(∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) | 
| 33 | 30, 32 | bitr2i 276 | . . . . 5
⊢
((∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑)) | 
| 34 | 33 | anbi2i 623 | . . . 4
⊢
((∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑)) ↔ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑))) | 
| 35 | 2, 34 | bitr3i 277 | . . 3
⊢
((∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑))) | 
| 36 |  | pm5.32 573 | . . 3
⊢
((∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 ↔ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑))) ↔ ((∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ [𝑢 / 𝑥][𝑣 / 𝑦]𝜑) ↔ (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑)))) | 
| 37 | 35, 36 | mpbir 231 | . 2
⊢
(∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣) → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 ↔ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑))) | 
| 38 | 1, 37 | sylbi 217 | 1
⊢ ((¬
∀𝑥 𝑥 = 𝑦 ∨ 𝑢 = 𝑣) → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 ↔ ∃𝑥∃𝑦((𝑥 = 𝑢 ∧ 𝑦 = 𝑣) ∧ 𝜑))) |