| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | bren 8996 | . . 3
⊢ (𝐴 ≈ 𝐵 ↔ ∃𝑓 𝑓:𝐴–1-1-onto→𝐵) | 
| 2 |  | f1odm 6851 | . . . . . . 7
⊢ (𝑓:𝐴–1-1-onto→𝐵 → dom 𝑓 = 𝐴) | 
| 3 |  | vex 3483 | . . . . . . . 8
⊢ 𝑓 ∈ V | 
| 4 | 3 | dmex 7932 | . . . . . . 7
⊢ dom 𝑓 ∈ V | 
| 5 | 2, 4 | eqeltrrdi 2849 | . . . . . 6
⊢ (𝑓:𝐴–1-1-onto→𝐵 → 𝐴 ∈ V) | 
| 6 |  | pwexg 5377 | . . . . . 6
⊢ (𝐴 ∈ V → 𝒫 𝐴 ∈ V) | 
| 7 |  | inex1g 5318 | . . . . . 6
⊢
(𝒫 𝐴 ∈
V → (𝒫 𝐴 ∩
{𝑥 ∣ 𝑥 ≈ 𝐶}) ∈ V) | 
| 8 | 5, 6, 7 | 3syl 18 | . . . . 5
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ∈ V) | 
| 9 |  | f1ofo 6854 | . . . . . . . 8
⊢ (𝑓:𝐴–1-1-onto→𝐵 → 𝑓:𝐴–onto→𝐵) | 
| 10 |  | forn 6822 | . . . . . . . 8
⊢ (𝑓:𝐴–onto→𝐵 → ran 𝑓 = 𝐵) | 
| 11 | 9, 10 | syl 17 | . . . . . . 7
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ran 𝑓 = 𝐵) | 
| 12 | 3 | rnex 7933 | . . . . . . 7
⊢ ran 𝑓 ∈ V | 
| 13 | 11, 12 | eqeltrrdi 2849 | . . . . . 6
⊢ (𝑓:𝐴–1-1-onto→𝐵 → 𝐵 ∈ V) | 
| 14 |  | pwexg 5377 | . . . . . 6
⊢ (𝐵 ∈ V → 𝒫 𝐵 ∈ V) | 
| 15 |  | inex1g 5318 | . . . . . 6
⊢
(𝒫 𝐵 ∈
V → (𝒫 𝐵 ∩
{𝑥 ∣ 𝑥 ≈ 𝐶}) ∈ V) | 
| 16 | 13, 14, 15 | 3syl 18 | . . . . 5
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ∈ V) | 
| 17 |  | f1of1 6846 | . . . . . . . . . . 11
⊢ (𝑓:𝐴–1-1-onto→𝐵 → 𝑓:𝐴–1-1→𝐵) | 
| 18 | 17 | adantr 480 | . . . . . . . . . 10
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → 𝑓:𝐴–1-1→𝐵) | 
| 19 | 13 | adantr 480 | . . . . . . . . . 10
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → 𝐵 ∈ V) | 
| 20 |  | simpr 484 | . . . . . . . . . 10
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → 𝑦 ⊆ 𝐴) | 
| 21 |  | vex 3483 | . . . . . . . . . . 11
⊢ 𝑦 ∈ V | 
| 22 | 21 | a1i 11 | . . . . . . . . . 10
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → 𝑦 ∈ V) | 
| 23 |  | f1imaen2g 9056 | . . . . . . . . . 10
⊢ (((𝑓:𝐴–1-1→𝐵 ∧ 𝐵 ∈ V) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑦 ∈ V)) → (𝑓 “ 𝑦) ≈ 𝑦) | 
| 24 | 18, 19, 20, 22, 23 | syl22anc 838 | . . . . . . . . 9
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → (𝑓 “ 𝑦) ≈ 𝑦) | 
| 25 |  | entr 9047 | . . . . . . . . 9
⊢ (((𝑓 “ 𝑦) ≈ 𝑦 ∧ 𝑦 ≈ 𝐶) → (𝑓 “ 𝑦) ≈ 𝐶) | 
| 26 | 24, 25 | sylan 580 | . . . . . . . 8
⊢ (((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) ∧ 𝑦 ≈ 𝐶) → (𝑓 “ 𝑦) ≈ 𝐶) | 
| 27 | 26 | expl 457 | . . . . . . 7
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ((𝑦 ⊆ 𝐴 ∧ 𝑦 ≈ 𝐶) → (𝑓 “ 𝑦) ≈ 𝐶)) | 
| 28 |  | imassrn 6088 | . . . . . . . . 9
⊢ (𝑓 “ 𝑦) ⊆ ran 𝑓 | 
| 29 | 28, 10 | sseqtrid 4025 | . . . . . . . 8
⊢ (𝑓:𝐴–onto→𝐵 → (𝑓 “ 𝑦) ⊆ 𝐵) | 
| 30 | 9, 29 | syl 17 | . . . . . . 7
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (𝑓 “ 𝑦) ⊆ 𝐵) | 
| 31 | 27, 30 | jctild 525 | . . . . . 6
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ((𝑦 ⊆ 𝐴 ∧ 𝑦 ≈ 𝐶) → ((𝑓 “ 𝑦) ⊆ 𝐵 ∧ (𝑓 “ 𝑦) ≈ 𝐶))) | 
| 32 |  | elin 3966 | . . . . . . 7
⊢ (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ (𝑦 ∈ 𝒫 𝐴 ∧ 𝑦 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 33 | 21 | elpw 4603 | . . . . . . . 8
⊢ (𝑦 ∈ 𝒫 𝐴 ↔ 𝑦 ⊆ 𝐴) | 
| 34 |  | breq1 5145 | . . . . . . . . 9
⊢ (𝑥 = 𝑦 → (𝑥 ≈ 𝐶 ↔ 𝑦 ≈ 𝐶)) | 
| 35 | 21, 34 | elab 3678 | . . . . . . . 8
⊢ (𝑦 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶} ↔ 𝑦 ≈ 𝐶) | 
| 36 | 33, 35 | anbi12i 628 | . . . . . . 7
⊢ ((𝑦 ∈ 𝒫 𝐴 ∧ 𝑦 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ (𝑦 ⊆ 𝐴 ∧ 𝑦 ≈ 𝐶)) | 
| 37 | 32, 36 | bitri 275 | . . . . . 6
⊢ (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ (𝑦 ⊆ 𝐴 ∧ 𝑦 ≈ 𝐶)) | 
| 38 |  | elin 3966 | . . . . . . 7
⊢ ((𝑓 “ 𝑦) ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ ((𝑓 “ 𝑦) ∈ 𝒫 𝐵 ∧ (𝑓 “ 𝑦) ∈ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 39 | 3 | imaex 7937 | . . . . . . . . 9
⊢ (𝑓 “ 𝑦) ∈ V | 
| 40 | 39 | elpw 4603 | . . . . . . . 8
⊢ ((𝑓 “ 𝑦) ∈ 𝒫 𝐵 ↔ (𝑓 “ 𝑦) ⊆ 𝐵) | 
| 41 |  | breq1 5145 | . . . . . . . . 9
⊢ (𝑥 = (𝑓 “ 𝑦) → (𝑥 ≈ 𝐶 ↔ (𝑓 “ 𝑦) ≈ 𝐶)) | 
| 42 | 39, 41 | elab 3678 | . . . . . . . 8
⊢ ((𝑓 “ 𝑦) ∈ {𝑥 ∣ 𝑥 ≈ 𝐶} ↔ (𝑓 “ 𝑦) ≈ 𝐶) | 
| 43 | 40, 42 | anbi12i 628 | . . . . . . 7
⊢ (((𝑓 “ 𝑦) ∈ 𝒫 𝐵 ∧ (𝑓 “ 𝑦) ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ ((𝑓 “ 𝑦) ⊆ 𝐵 ∧ (𝑓 “ 𝑦) ≈ 𝐶)) | 
| 44 | 38, 43 | bitri 275 | . . . . . 6
⊢ ((𝑓 “ 𝑦) ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ ((𝑓 “ 𝑦) ⊆ 𝐵 ∧ (𝑓 “ 𝑦) ≈ 𝐶)) | 
| 45 | 31, 37, 44 | 3imtr4g 296 | . . . . 5
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) → (𝑓 “ 𝑦) ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}))) | 
| 46 |  | f1ocnv 6859 | . . . . . . 7
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ◡𝑓:𝐵–1-1-onto→𝐴) | 
| 47 |  | f1of1 6846 | . . . . . . . . . . . 12
⊢ (◡𝑓:𝐵–1-1-onto→𝐴 → ◡𝑓:𝐵–1-1→𝐴) | 
| 48 |  | f1f1orn 6858 | . . . . . . . . . . . 12
⊢ (◡𝑓:𝐵–1-1→𝐴 → ◡𝑓:𝐵–1-1-onto→ran
◡𝑓) | 
| 49 |  | f1of1 6846 | . . . . . . . . . . . 12
⊢ (◡𝑓:𝐵–1-1-onto→ran
◡𝑓 → ◡𝑓:𝐵–1-1→ran ◡𝑓) | 
| 50 | 47, 48, 49 | 3syl 18 | . . . . . . . . . . 11
⊢ (◡𝑓:𝐵–1-1-onto→𝐴 → ◡𝑓:𝐵–1-1→ran ◡𝑓) | 
| 51 |  | vex 3483 | . . . . . . . . . . . 12
⊢ 𝑧 ∈ V | 
| 52 | 51 | f1imaen 9058 | . . . . . . . . . . 11
⊢ ((◡𝑓:𝐵–1-1→ran ◡𝑓 ∧ 𝑧 ⊆ 𝐵) → (◡𝑓 “ 𝑧) ≈ 𝑧) | 
| 53 | 50, 52 | sylan 580 | . . . . . . . . . 10
⊢ ((◡𝑓:𝐵–1-1-onto→𝐴 ∧ 𝑧 ⊆ 𝐵) → (◡𝑓 “ 𝑧) ≈ 𝑧) | 
| 54 |  | entr 9047 | . . . . . . . . . 10
⊢ (((◡𝑓 “ 𝑧) ≈ 𝑧 ∧ 𝑧 ≈ 𝐶) → (◡𝑓 “ 𝑧) ≈ 𝐶) | 
| 55 | 53, 54 | sylan 580 | . . . . . . . . 9
⊢ (((◡𝑓:𝐵–1-1-onto→𝐴 ∧ 𝑧 ⊆ 𝐵) ∧ 𝑧 ≈ 𝐶) → (◡𝑓 “ 𝑧) ≈ 𝐶) | 
| 56 | 55 | expl 457 | . . . . . . . 8
⊢ (◡𝑓:𝐵–1-1-onto→𝐴 → ((𝑧 ⊆ 𝐵 ∧ 𝑧 ≈ 𝐶) → (◡𝑓 “ 𝑧) ≈ 𝐶)) | 
| 57 |  | f1ofo 6854 | . . . . . . . . 9
⊢ (◡𝑓:𝐵–1-1-onto→𝐴 → ◡𝑓:𝐵–onto→𝐴) | 
| 58 |  | imassrn 6088 | . . . . . . . . . 10
⊢ (◡𝑓 “ 𝑧) ⊆ ran ◡𝑓 | 
| 59 |  | forn 6822 | . . . . . . . . . 10
⊢ (◡𝑓:𝐵–onto→𝐴 → ran ◡𝑓 = 𝐴) | 
| 60 | 58, 59 | sseqtrid 4025 | . . . . . . . . 9
⊢ (◡𝑓:𝐵–onto→𝐴 → (◡𝑓 “ 𝑧) ⊆ 𝐴) | 
| 61 | 57, 60 | syl 17 | . . . . . . . 8
⊢ (◡𝑓:𝐵–1-1-onto→𝐴 → (◡𝑓 “ 𝑧) ⊆ 𝐴) | 
| 62 | 56, 61 | jctild 525 | . . . . . . 7
⊢ (◡𝑓:𝐵–1-1-onto→𝐴 → ((𝑧 ⊆ 𝐵 ∧ 𝑧 ≈ 𝐶) → ((◡𝑓 “ 𝑧) ⊆ 𝐴 ∧ (◡𝑓 “ 𝑧) ≈ 𝐶))) | 
| 63 | 46, 62 | syl 17 | . . . . . 6
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ((𝑧 ⊆ 𝐵 ∧ 𝑧 ≈ 𝐶) → ((◡𝑓 “ 𝑧) ⊆ 𝐴 ∧ (◡𝑓 “ 𝑧) ≈ 𝐶))) | 
| 64 |  | elin 3966 | . . . . . . 7
⊢ (𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ (𝑧 ∈ 𝒫 𝐵 ∧ 𝑧 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 65 | 51 | elpw 4603 | . . . . . . . 8
⊢ (𝑧 ∈ 𝒫 𝐵 ↔ 𝑧 ⊆ 𝐵) | 
| 66 |  | breq1 5145 | . . . . . . . . 9
⊢ (𝑥 = 𝑧 → (𝑥 ≈ 𝐶 ↔ 𝑧 ≈ 𝐶)) | 
| 67 | 51, 66 | elab 3678 | . . . . . . . 8
⊢ (𝑧 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶} ↔ 𝑧 ≈ 𝐶) | 
| 68 | 65, 67 | anbi12i 628 | . . . . . . 7
⊢ ((𝑧 ∈ 𝒫 𝐵 ∧ 𝑧 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ (𝑧 ⊆ 𝐵 ∧ 𝑧 ≈ 𝐶)) | 
| 69 | 64, 68 | bitri 275 | . . . . . 6
⊢ (𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ (𝑧 ⊆ 𝐵 ∧ 𝑧 ≈ 𝐶)) | 
| 70 |  | elin 3966 | . . . . . . 7
⊢ ((◡𝑓 “ 𝑧) ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ ((◡𝑓 “ 𝑧) ∈ 𝒫 𝐴 ∧ (◡𝑓 “ 𝑧) ∈ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 71 | 3 | cnvex 7948 | . . . . . . . . . 10
⊢ ◡𝑓 ∈ V | 
| 72 | 71 | imaex 7937 | . . . . . . . . 9
⊢ (◡𝑓 “ 𝑧) ∈ V | 
| 73 | 72 | elpw 4603 | . . . . . . . 8
⊢ ((◡𝑓 “ 𝑧) ∈ 𝒫 𝐴 ↔ (◡𝑓 “ 𝑧) ⊆ 𝐴) | 
| 74 |  | breq1 5145 | . . . . . . . . 9
⊢ (𝑥 = (◡𝑓 “ 𝑧) → (𝑥 ≈ 𝐶 ↔ (◡𝑓 “ 𝑧) ≈ 𝐶)) | 
| 75 | 72, 74 | elab 3678 | . . . . . . . 8
⊢ ((◡𝑓 “ 𝑧) ∈ {𝑥 ∣ 𝑥 ≈ 𝐶} ↔ (◡𝑓 “ 𝑧) ≈ 𝐶) | 
| 76 | 73, 75 | anbi12i 628 | . . . . . . 7
⊢ (((◡𝑓 “ 𝑧) ∈ 𝒫 𝐴 ∧ (◡𝑓 “ 𝑧) ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ ((◡𝑓 “ 𝑧) ⊆ 𝐴 ∧ (◡𝑓 “ 𝑧) ≈ 𝐶)) | 
| 77 | 70, 76 | bitri 275 | . . . . . 6
⊢ ((◡𝑓 “ 𝑧) ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ↔ ((◡𝑓 “ 𝑧) ⊆ 𝐴 ∧ (◡𝑓 “ 𝑧) ≈ 𝐶)) | 
| 78 | 63, 69, 77 | 3imtr4g 296 | . . . . 5
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) → (◡𝑓 “ 𝑧) ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}))) | 
| 79 |  | simpl 482 | . . . . . . . . . . 11
⊢ ((𝑧 ∈ 𝒫 𝐵 ∧ 𝑧 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) → 𝑧 ∈ 𝒫 𝐵) | 
| 80 | 79 | elpwid 4608 | . . . . . . . . . 10
⊢ ((𝑧 ∈ 𝒫 𝐵 ∧ 𝑧 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) → 𝑧 ⊆ 𝐵) | 
| 81 | 64, 80 | sylbi 217 | . . . . . . . . 9
⊢ (𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) → 𝑧 ⊆ 𝐵) | 
| 82 |  | imaeq2 6073 | . . . . . . . . . . . 12
⊢ (𝑦 = (◡𝑓 “ 𝑧) → (𝑓 “ 𝑦) = (𝑓 “ (◡𝑓 “ 𝑧))) | 
| 83 |  | f1orel 6850 | . . . . . . . . . . . . . . . 16
⊢ (𝑓:𝐴–1-1-onto→𝐵 → Rel 𝑓) | 
| 84 |  | dfrel2 6208 | . . . . . . . . . . . . . . . 16
⊢ (Rel
𝑓 ↔ ◡◡𝑓 = 𝑓) | 
| 85 | 83, 84 | sylib 218 | . . . . . . . . . . . . . . 15
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ◡◡𝑓 = 𝑓) | 
| 86 | 85 | imaeq1d 6076 | . . . . . . . . . . . . . 14
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (◡◡𝑓 “ (◡𝑓 “ 𝑧)) = (𝑓 “ (◡𝑓 “ 𝑧))) | 
| 87 | 86 | adantr 480 | . . . . . . . . . . . . 13
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ⊆ 𝐵) → (◡◡𝑓 “ (◡𝑓 “ 𝑧)) = (𝑓 “ (◡𝑓 “ 𝑧))) | 
| 88 | 46, 47 | syl 17 | . . . . . . . . . . . . . 14
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ◡𝑓:𝐵–1-1→𝐴) | 
| 89 |  | f1imacnv 6863 | . . . . . . . . . . . . . 14
⊢ ((◡𝑓:𝐵–1-1→𝐴 ∧ 𝑧 ⊆ 𝐵) → (◡◡𝑓 “ (◡𝑓 “ 𝑧)) = 𝑧) | 
| 90 | 88, 89 | sylan 580 | . . . . . . . . . . . . 13
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ⊆ 𝐵) → (◡◡𝑓 “ (◡𝑓 “ 𝑧)) = 𝑧) | 
| 91 | 87, 90 | eqtr3d 2778 | . . . . . . . . . . . 12
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ⊆ 𝐵) → (𝑓 “ (◡𝑓 “ 𝑧)) = 𝑧) | 
| 92 | 82, 91 | sylan9eqr 2798 | . . . . . . . . . . 11
⊢ (((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ⊆ 𝐵) ∧ 𝑦 = (◡𝑓 “ 𝑧)) → (𝑓 “ 𝑦) = 𝑧) | 
| 93 | 92 | eqcomd 2742 | . . . . . . . . . 10
⊢ (((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ⊆ 𝐵) ∧ 𝑦 = (◡𝑓 “ 𝑧)) → 𝑧 = (𝑓 “ 𝑦)) | 
| 94 | 93 | ex 412 | . . . . . . . . 9
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ⊆ 𝐵) → (𝑦 = (◡𝑓 “ 𝑧) → 𝑧 = (𝑓 “ 𝑦))) | 
| 95 | 81, 94 | sylan2 593 | . . . . . . . 8
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶})) → (𝑦 = (◡𝑓 “ 𝑧) → 𝑧 = (𝑓 “ 𝑦))) | 
| 96 | 95 | adantrl 716 | . . . . . . 7
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ∧ 𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}))) → (𝑦 = (◡𝑓 “ 𝑧) → 𝑧 = (𝑓 “ 𝑦))) | 
| 97 |  | simpl 482 | . . . . . . . . . . 11
⊢ ((𝑦 ∈ 𝒫 𝐴 ∧ 𝑦 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) → 𝑦 ∈ 𝒫 𝐴) | 
| 98 | 97 | elpwid 4608 | . . . . . . . . . 10
⊢ ((𝑦 ∈ 𝒫 𝐴 ∧ 𝑦 ∈ {𝑥 ∣ 𝑥 ≈ 𝐶}) → 𝑦 ⊆ 𝐴) | 
| 99 | 32, 98 | sylbi 217 | . . . . . . . . 9
⊢ (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) → 𝑦 ⊆ 𝐴) | 
| 100 |  | imaeq2 6073 | . . . . . . . . . . . 12
⊢ (𝑧 = (𝑓 “ 𝑦) → (◡𝑓 “ 𝑧) = (◡𝑓 “ (𝑓 “ 𝑦))) | 
| 101 |  | f1imacnv 6863 | . . . . . . . . . . . . 13
⊢ ((𝑓:𝐴–1-1→𝐵 ∧ 𝑦 ⊆ 𝐴) → (◡𝑓 “ (𝑓 “ 𝑦)) = 𝑦) | 
| 102 | 17, 101 | sylan 580 | . . . . . . . . . . . 12
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → (◡𝑓 “ (𝑓 “ 𝑦)) = 𝑦) | 
| 103 | 100, 102 | sylan9eqr 2798 | . . . . . . . . . . 11
⊢ (((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) ∧ 𝑧 = (𝑓 “ 𝑦)) → (◡𝑓 “ 𝑧) = 𝑦) | 
| 104 | 103 | eqcomd 2742 | . . . . . . . . . 10
⊢ (((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) ∧ 𝑧 = (𝑓 “ 𝑦)) → 𝑦 = (◡𝑓 “ 𝑧)) | 
| 105 | 104 | ex 412 | . . . . . . . . 9
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ⊆ 𝐴) → (𝑧 = (𝑓 “ 𝑦) → 𝑦 = (◡𝑓 “ 𝑧))) | 
| 106 | 99, 105 | sylan2 593 | . . . . . . . 8
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ 𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶})) → (𝑧 = (𝑓 “ 𝑦) → 𝑦 = (◡𝑓 “ 𝑧))) | 
| 107 | 106 | adantrr 717 | . . . . . . 7
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ∧ 𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}))) → (𝑧 = (𝑓 “ 𝑦) → 𝑦 = (◡𝑓 “ 𝑧))) | 
| 108 | 96, 107 | impbid 212 | . . . . . 6
⊢ ((𝑓:𝐴–1-1-onto→𝐵 ∧ (𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ∧ 𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}))) → (𝑦 = (◡𝑓 “ 𝑧) ↔ 𝑧 = (𝑓 “ 𝑦))) | 
| 109 | 108 | ex 412 | . . . . 5
⊢ (𝑓:𝐴–1-1-onto→𝐵 → ((𝑦 ∈ (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ∧ 𝑧 ∈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶})) → (𝑦 = (◡𝑓 “ 𝑧) ↔ 𝑧 = (𝑓 “ 𝑦)))) | 
| 110 | 8, 16, 45, 78, 109 | en3d 9030 | . . . 4
⊢ (𝑓:𝐴–1-1-onto→𝐵 → (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ≈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 111 | 110 | exlimiv 1929 | . . 3
⊢
(∃𝑓 𝑓:𝐴–1-1-onto→𝐵 → (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ≈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 112 | 1, 111 | sylbi 217 | . 2
⊢ (𝐴 ≈ 𝐵 → (𝒫 𝐴 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) ≈ (𝒫 𝐵 ∩ {𝑥 ∣ 𝑥 ≈ 𝐶})) | 
| 113 |  | df-pw 4601 | . . . 4
⊢ 𝒫
𝐴 = {𝑥 ∣ 𝑥 ⊆ 𝐴} | 
| 114 | 113 | ineq1i 4215 | . . 3
⊢
(𝒫 𝐴 ∩
{𝑥 ∣ 𝑥 ≈ 𝐶}) = ({𝑥 ∣ 𝑥 ⊆ 𝐴} ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) | 
| 115 |  | inab 4308 | . . 3
⊢ ({𝑥 ∣ 𝑥 ⊆ 𝐴} ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) = {𝑥 ∣ (𝑥 ⊆ 𝐴 ∧ 𝑥 ≈ 𝐶)} | 
| 116 | 114, 115 | eqtri 2764 | . 2
⊢
(𝒫 𝐴 ∩
{𝑥 ∣ 𝑥 ≈ 𝐶}) = {𝑥 ∣ (𝑥 ⊆ 𝐴 ∧ 𝑥 ≈ 𝐶)} | 
| 117 |  | df-pw 4601 | . . . 4
⊢ 𝒫
𝐵 = {𝑥 ∣ 𝑥 ⊆ 𝐵} | 
| 118 | 117 | ineq1i 4215 | . . 3
⊢
(𝒫 𝐵 ∩
{𝑥 ∣ 𝑥 ≈ 𝐶}) = ({𝑥 ∣ 𝑥 ⊆ 𝐵} ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) | 
| 119 |  | inab 4308 | . . 3
⊢ ({𝑥 ∣ 𝑥 ⊆ 𝐵} ∩ {𝑥 ∣ 𝑥 ≈ 𝐶}) = {𝑥 ∣ (𝑥 ⊆ 𝐵 ∧ 𝑥 ≈ 𝐶)} | 
| 120 | 118, 119 | eqtri 2764 | . 2
⊢
(𝒫 𝐵 ∩
{𝑥 ∣ 𝑥 ≈ 𝐶}) = {𝑥 ∣ (𝑥 ⊆ 𝐵 ∧ 𝑥 ≈ 𝐶)} | 
| 121 | 112, 116,
120 | 3brtr3g 5175 | 1
⊢ (𝐴 ≈ 𝐵 → {𝑥 ∣ (𝑥 ⊆ 𝐴 ∧ 𝑥 ≈ 𝐶)} ≈ {𝑥 ∣ (𝑥 ⊆ 𝐵 ∧ 𝑥 ≈ 𝐶)}) |