| Step | Hyp | Ref
| Expression |
| 1 | | 2onn 8659 |
. . . . . . . . . 10
⊢
2o ∈ ω |
| 2 | | nnfi 9186 |
. . . . . . . . . 10
⊢
(2o ∈ ω → 2o ∈
Fin) |
| 3 | 1, 2 | ax-mp 5 |
. . . . . . . . 9
⊢
2o ∈ Fin |
| 4 | | enfi 9206 |
. . . . . . . . 9
⊢ (𝑃 ≈ 2o →
(𝑃 ∈ Fin ↔
2o ∈ Fin)) |
| 5 | 3, 4 | mpbiri 258 |
. . . . . . . 8
⊢ (𝑃 ≈ 2o →
𝑃 ∈
Fin) |
| 6 | 5 | adantl 481 |
. . . . . . 7
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → 𝑃 ∈ Fin) |
| 7 | | diffi 9194 |
. . . . . . 7
⊢ (𝑃 ∈ Fin → (𝑃 ∖ {𝑋}) ∈ Fin) |
| 8 | 6, 7 | syl 17 |
. . . . . 6
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → (𝑃 ∖ {𝑋}) ∈ Fin) |
| 9 | 8 | cardidd 10568 |
. . . . 5
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) →
(card‘(𝑃 ∖
{𝑋})) ≈ (𝑃 ∖ {𝑋})) |
| 10 | 9 | ensymd 9024 |
. . . 4
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → (𝑃 ∖ {𝑋}) ≈ (card‘(𝑃 ∖ {𝑋}))) |
| 11 | | simpl 482 |
. . . . . . 7
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → 𝑋 ∈ 𝑃) |
| 12 | | dif1card 10029 |
. . . . . . 7
⊢ ((𝑃 ∈ Fin ∧ 𝑋 ∈ 𝑃) → (card‘𝑃) = suc (card‘(𝑃 ∖ {𝑋}))) |
| 13 | 6, 11, 12 | syl2anc 584 |
. . . . . 6
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) →
(card‘𝑃) = suc
(card‘(𝑃 ∖
{𝑋}))) |
| 14 | | cardennn 10002 |
. . . . . . . . 9
⊢ ((𝑃 ≈ 2o ∧
2o ∈ ω) → (card‘𝑃) = 2o) |
| 15 | 1, 14 | mpan2 691 |
. . . . . . . 8
⊢ (𝑃 ≈ 2o →
(card‘𝑃) =
2o) |
| 16 | | df-2o 8486 |
. . . . . . . 8
⊢
2o = suc 1o |
| 17 | 15, 16 | eqtrdi 2787 |
. . . . . . 7
⊢ (𝑃 ≈ 2o →
(card‘𝑃) = suc
1o) |
| 18 | 17 | adantl 481 |
. . . . . 6
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) →
(card‘𝑃) = suc
1o) |
| 19 | 13, 18 | eqtr3d 2773 |
. . . . 5
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → suc
(card‘(𝑃 ∖
{𝑋})) = suc
1o) |
| 20 | | suc11reg 9638 |
. . . . 5
⊢ (suc
(card‘(𝑃 ∖
{𝑋})) = suc 1o
↔ (card‘(𝑃
∖ {𝑋})) =
1o) |
| 21 | 19, 20 | sylib 218 |
. . . 4
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) →
(card‘(𝑃 ∖
{𝑋})) =
1o) |
| 22 | 10, 21 | breqtrd 5150 |
. . 3
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → (𝑃 ∖ {𝑋}) ≈ 1o) |
| 23 | | en1 9043 |
. . 3
⊢ ((𝑃 ∖ {𝑋}) ≈ 1o ↔ ∃𝑥(𝑃 ∖ {𝑋}) = {𝑥}) |
| 24 | 22, 23 | sylib 218 |
. 2
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → ∃𝑥(𝑃 ∖ {𝑋}) = {𝑥}) |
| 25 | | simplll 774 |
. . . . . . 7
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → 𝑋 ∈ 𝑃) |
| 26 | 25 | elexd 3488 |
. . . . . 6
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → 𝑋 ∈ V) |
| 27 | | simplr 768 |
. . . . . . . . . . 11
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → (𝑃 ∖ {𝑋}) = {𝑥}) |
| 28 | | sneqbg 4824 |
. . . . . . . . . . . . 13
⊢ (𝑋 ∈ 𝑃 → ({𝑋} = {𝑥} ↔ 𝑋 = 𝑥)) |
| 29 | 28 | biimpar 477 |
. . . . . . . . . . . 12
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑋 = 𝑥) → {𝑋} = {𝑥}) |
| 30 | 29 | ad4ant14 752 |
. . . . . . . . . . 11
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → {𝑋} = {𝑥}) |
| 31 | 27, 30 | eqtr4d 2774 |
. . . . . . . . . 10
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → (𝑃 ∖ {𝑋}) = {𝑋}) |
| 32 | 31 | ineq2d 4200 |
. . . . . . . . 9
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → ({𝑋} ∩ (𝑃 ∖ {𝑋})) = ({𝑋} ∩ {𝑋})) |
| 33 | | disjdif 4452 |
. . . . . . . . 9
⊢ ({𝑋} ∩ (𝑃 ∖ {𝑋})) = ∅ |
| 34 | | inidm 4207 |
. . . . . . . . 9
⊢ ({𝑋} ∩ {𝑋}) = {𝑋} |
| 35 | 32, 33, 34 | 3eqtr3g 2794 |
. . . . . . . 8
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → ∅ = {𝑋}) |
| 36 | 35 | eqcomd 2742 |
. . . . . . 7
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → {𝑋} = ∅) |
| 37 | | snprc 4698 |
. . . . . . 7
⊢ (¬
𝑋 ∈ V ↔ {𝑋} = ∅) |
| 38 | 36, 37 | sylibr 234 |
. . . . . 6
⊢ ((((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) ∧ 𝑋 = 𝑥) → ¬ 𝑋 ∈ V) |
| 39 | 26, 38 | pm2.65da 816 |
. . . . 5
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → ¬ 𝑋 = 𝑥) |
| 40 | 39 | neqned 2940 |
. . . 4
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → 𝑋 ≠ 𝑥) |
| 41 | | simpr 484 |
. . . . . 6
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → (𝑃 ∖ {𝑋}) = {𝑥}) |
| 42 | 41 | unieqd 4901 |
. . . . 5
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → ∪ (𝑃 ∖ {𝑋}) = ∪ {𝑥}) |
| 43 | | unisnv 4908 |
. . . . 5
⊢ ∪ {𝑥}
= 𝑥 |
| 44 | 42, 43 | eqtrdi 2787 |
. . . 4
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → ∪ (𝑃 ∖ {𝑋}) = 𝑥) |
| 45 | 40, 44 | neeqtrrd 3007 |
. . 3
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → 𝑋 ≠ ∪ (𝑃 ∖ {𝑋})) |
| 46 | 45 | necomd 2988 |
. 2
⊢ (((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) ∧ (𝑃 ∖ {𝑋}) = {𝑥}) → ∪ (𝑃 ∖ {𝑋}) ≠ 𝑋) |
| 47 | 24, 46 | exlimddv 1935 |
1
⊢ ((𝑋 ∈ 𝑃 ∧ 𝑃 ≈ 2o) → ∪ (𝑃
∖ {𝑋}) ≠ 𝑋) |