Proof of Theorem allbutfi
| Step | Hyp | Ref
| Expression |
| 1 | | allbutfi.a |
. . . . . 6
⊢ 𝐴 = ∪ 𝑛 ∈ 𝑍 ∩ 𝑚 ∈
(ℤ≥‘𝑛)𝐵 |
| 2 | 1 | eleq2i 2693 |
. . . . 5
⊢ (𝑋 ∈ 𝐴 ↔ 𝑋 ∈ ∪
𝑛 ∈ 𝑍 ∩ 𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 3 | 2 | biimpi 206 |
. . . 4
⊢ (𝑋 ∈ 𝐴 → 𝑋 ∈ ∪
𝑛 ∈ 𝑍 ∩ 𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 4 | | eliun 4524 |
. . . 4
⊢ (𝑋 ∈ ∪ 𝑛 ∈ 𝑍 ∩ 𝑚 ∈
(ℤ≥‘𝑛)𝐵 ↔ ∃𝑛 ∈ 𝑍 𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 5 | 3, 4 | sylib 208 |
. . 3
⊢ (𝑋 ∈ 𝐴 → ∃𝑛 ∈ 𝑍 𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 6 | | nfcv 2764 |
. . . . 5
⊢
Ⅎ𝑛𝑋 |
| 7 | | nfiu1 4550 |
. . . . . 6
⊢
Ⅎ𝑛∪ 𝑛 ∈ 𝑍 ∩ 𝑚 ∈
(ℤ≥‘𝑛)𝐵 |
| 8 | 1, 7 | nfcxfr 2762 |
. . . . 5
⊢
Ⅎ𝑛𝐴 |
| 9 | 6, 8 | nfel 2777 |
. . . 4
⊢
Ⅎ𝑛 𝑋 ∈ 𝐴 |
| 10 | | eliin 4525 |
. . . . . 6
⊢ (𝑋 ∈ 𝐴 → (𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 ↔ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵)) |
| 11 | 10 | biimpd 219 |
. . . . 5
⊢ (𝑋 ∈ 𝐴 → (𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 → ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵)) |
| 12 | 11 | a1d 25 |
. . . 4
⊢ (𝑋 ∈ 𝐴 → (𝑛 ∈ 𝑍 → (𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 → ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵))) |
| 13 | 9, 12 | reximdai 3012 |
. . 3
⊢ (𝑋 ∈ 𝐴 → (∃𝑛 ∈ 𝑍 𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 → ∃𝑛 ∈ 𝑍 ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵)) |
| 14 | 5, 13 | mpd 15 |
. 2
⊢ (𝑋 ∈ 𝐴 → ∃𝑛 ∈ 𝑍 ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵) |
| 15 | | simpr 477 |
. . . . . . 7
⊢ ((𝑛 ∈ 𝑍 ∧ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵) → ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵) |
| 16 | | allbutfi.z |
. . . . . . . . . . . . 13
⊢ 𝑍 =
(ℤ≥‘𝑀) |
| 17 | 16 | eleq2i 2693 |
. . . . . . . . . . . 12
⊢ (𝑛 ∈ 𝑍 ↔ 𝑛 ∈ (ℤ≥‘𝑀)) |
| 18 | 17 | biimpi 206 |
. . . . . . . . . . 11
⊢ (𝑛 ∈ 𝑍 → 𝑛 ∈ (ℤ≥‘𝑀)) |
| 19 | | eluzelz 11697 |
. . . . . . . . . . 11
⊢ (𝑛 ∈
(ℤ≥‘𝑀) → 𝑛 ∈ ℤ) |
| 20 | | uzid 11702 |
. . . . . . . . . . 11
⊢ (𝑛 ∈ ℤ → 𝑛 ∈
(ℤ≥‘𝑛)) |
| 21 | 18, 19, 20 | 3syl 18 |
. . . . . . . . . 10
⊢ (𝑛 ∈ 𝑍 → 𝑛 ∈ (ℤ≥‘𝑛)) |
| 22 | | ne0i 3921 |
. . . . . . . . . 10
⊢ (𝑛 ∈
(ℤ≥‘𝑛) → (ℤ≥‘𝑛) ≠ ∅) |
| 23 | 21, 22 | syl 17 |
. . . . . . . . 9
⊢ (𝑛 ∈ 𝑍 → (ℤ≥‘𝑛) ≠ ∅) |
| 24 | | eliin2 39299 |
. . . . . . . . 9
⊢
((ℤ≥‘𝑛) ≠ ∅ → (𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 ↔ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵)) |
| 25 | 23, 24 | syl 17 |
. . . . . . . 8
⊢ (𝑛 ∈ 𝑍 → (𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 ↔ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵)) |
| 26 | 25 | adantr 481 |
. . . . . . 7
⊢ ((𝑛 ∈ 𝑍 ∧ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵) → (𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵 ↔ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵)) |
| 27 | 15, 26 | mpbird 247 |
. . . . . 6
⊢ ((𝑛 ∈ 𝑍 ∧ ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵) → 𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 28 | 27 | ex 450 |
. . . . 5
⊢ (𝑛 ∈ 𝑍 → (∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵 → 𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵)) |
| 29 | 28 | reximia 3009 |
. . . 4
⊢
(∃𝑛 ∈
𝑍 ∀𝑚 ∈
(ℤ≥‘𝑛)𝑋 ∈ 𝐵 → ∃𝑛 ∈ 𝑍 𝑋 ∈ ∩
𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 30 | 29, 4 | sylibr 224 |
. . 3
⊢
(∃𝑛 ∈
𝑍 ∀𝑚 ∈
(ℤ≥‘𝑛)𝑋 ∈ 𝐵 → 𝑋 ∈ ∪
𝑛 ∈ 𝑍 ∩ 𝑚 ∈
(ℤ≥‘𝑛)𝐵) |
| 31 | 30, 1 | syl6eleqr 2712 |
. 2
⊢
(∃𝑛 ∈
𝑍 ∀𝑚 ∈
(ℤ≥‘𝑛)𝑋 ∈ 𝐵 → 𝑋 ∈ 𝐴) |
| 32 | 14, 31 | impbii 199 |
1
⊢ (𝑋 ∈ 𝐴 ↔ ∃𝑛 ∈ 𝑍 ∀𝑚 ∈ (ℤ≥‘𝑛)𝑋 ∈ 𝐵) |