| Step | Hyp | Ref
| Expression |
| 1 | | vsnex 5384 |
. . 3
⊢ {𝑥} ∈ V |
| 2 | | eleq1w 2811 |
. . . 4
⊢ (𝑦 = 𝑥 → (𝑦 ∈ {𝑥} ↔ 𝑥 ∈ {𝑥})) |
| 3 | | vsnid 4623 |
. . . 4
⊢ 𝑥 ∈ {𝑥} |
| 4 | 2, 3 | speivw 1973 |
. . 3
⊢
∃𝑦 𝑦 ∈ {𝑥} |
| 5 | | zfregcl 9523 |
. . 3
⊢ ({𝑥} ∈ V → (∃𝑦 𝑦 ∈ {𝑥} → ∃𝑦 ∈ {𝑥}∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥})) |
| 6 | 1, 4, 5 | mp2 9 |
. 2
⊢
∃𝑦 ∈
{𝑥}∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥} |
| 7 | | velsn 4601 |
. . . . . . 7
⊢ (𝑦 ∈ {𝑥} ↔ 𝑦 = 𝑥) |
| 8 | | ax9 2123 |
. . . . . . . . 9
⊢ (𝑥 = 𝑦 → (𝑥 ∈ 𝑥 → 𝑥 ∈ 𝑦)) |
| 9 | 8 | equcoms 2020 |
. . . . . . . 8
⊢ (𝑦 = 𝑥 → (𝑥 ∈ 𝑥 → 𝑥 ∈ 𝑦)) |
| 10 | 9 | com12 32 |
. . . . . . 7
⊢ (𝑥 ∈ 𝑥 → (𝑦 = 𝑥 → 𝑥 ∈ 𝑦)) |
| 11 | 7, 10 | biimtrid 242 |
. . . . . 6
⊢ (𝑥 ∈ 𝑥 → (𝑦 ∈ {𝑥} → 𝑥 ∈ 𝑦)) |
| 12 | | eleq1w 2811 |
. . . . . . . . 9
⊢ (𝑧 = 𝑥 → (𝑧 ∈ {𝑥} ↔ 𝑥 ∈ {𝑥})) |
| 13 | 12 | notbid 318 |
. . . . . . . 8
⊢ (𝑧 = 𝑥 → (¬ 𝑧 ∈ {𝑥} ↔ ¬ 𝑥 ∈ {𝑥})) |
| 14 | 13 | rspccv 3582 |
. . . . . . 7
⊢
(∀𝑧 ∈
𝑦 ¬ 𝑧 ∈ {𝑥} → (𝑥 ∈ 𝑦 → ¬ 𝑥 ∈ {𝑥})) |
| 15 | 3, 14 | mt2i 137 |
. . . . . 6
⊢
(∀𝑧 ∈
𝑦 ¬ 𝑧 ∈ {𝑥} → ¬ 𝑥 ∈ 𝑦) |
| 16 | 11, 15 | nsyli 157 |
. . . . 5
⊢ (𝑥 ∈ 𝑥 → (∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥} → ¬ 𝑦 ∈ {𝑥})) |
| 17 | 16 | con2d 134 |
. . . 4
⊢ (𝑥 ∈ 𝑥 → (𝑦 ∈ {𝑥} → ¬ ∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥})) |
| 18 | 17 | ralrimiv 3124 |
. . 3
⊢ (𝑥 ∈ 𝑥 → ∀𝑦 ∈ {𝑥} ¬ ∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥}) |
| 19 | | ralnex 3055 |
. . 3
⊢
(∀𝑦 ∈
{𝑥} ¬ ∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥} ↔ ¬ ∃𝑦 ∈ {𝑥}∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥}) |
| 20 | 18, 19 | sylib 218 |
. 2
⊢ (𝑥 ∈ 𝑥 → ¬ ∃𝑦 ∈ {𝑥}∀𝑧 ∈ 𝑦 ¬ 𝑧 ∈ {𝑥}) |
| 21 | 6, 20 | mt2 200 |
1
⊢ ¬
𝑥 ∈ 𝑥 |