| Step | Hyp | Ref
| Expression |
| 1 | | bdvsn 15520 |
. . . 4
⊢
BOUNDED 𝑧 = {𝑥} |
| 2 | | bdcpr 15517 |
. . . . . . 7
⊢
BOUNDED {𝑥, 𝑦} |
| 3 | 2 | bdss 15510 |
. . . . . 6
⊢
BOUNDED 𝑧 ⊆ {𝑥, 𝑦} |
| 4 | | ax-bdel 15467 |
. . . . . . . 8
⊢
BOUNDED 𝑥 ∈ 𝑧 |
| 5 | | ax-bdel 15467 |
. . . . . . . 8
⊢
BOUNDED 𝑦 ∈ 𝑧 |
| 6 | 4, 5 | ax-bdan 15461 |
. . . . . . 7
⊢
BOUNDED (𝑥 ∈ 𝑧 ∧ 𝑦 ∈ 𝑧) |
| 7 | | vex 2766 |
. . . . . . . . . . 11
⊢ 𝑥 ∈ V |
| 8 | 7 | prid1 3728 |
. . . . . . . . . 10
⊢ 𝑥 ∈ {𝑥, 𝑦} |
| 9 | | ssel 3177 |
. . . . . . . . . 10
⊢ ({𝑥, 𝑦} ⊆ 𝑧 → (𝑥 ∈ {𝑥, 𝑦} → 𝑥 ∈ 𝑧)) |
| 10 | 8, 9 | mpi 15 |
. . . . . . . . 9
⊢ ({𝑥, 𝑦} ⊆ 𝑧 → 𝑥 ∈ 𝑧) |
| 11 | | vex 2766 |
. . . . . . . . . . 11
⊢ 𝑦 ∈ V |
| 12 | 11 | prid2 3729 |
. . . . . . . . . 10
⊢ 𝑦 ∈ {𝑥, 𝑦} |
| 13 | | ssel 3177 |
. . . . . . . . . 10
⊢ ({𝑥, 𝑦} ⊆ 𝑧 → (𝑦 ∈ {𝑥, 𝑦} → 𝑦 ∈ 𝑧)) |
| 14 | 12, 13 | mpi 15 |
. . . . . . . . 9
⊢ ({𝑥, 𝑦} ⊆ 𝑧 → 𝑦 ∈ 𝑧) |
| 15 | 10, 14 | jca 306 |
. . . . . . . 8
⊢ ({𝑥, 𝑦} ⊆ 𝑧 → (𝑥 ∈ 𝑧 ∧ 𝑦 ∈ 𝑧)) |
| 16 | | prssi 3780 |
. . . . . . . 8
⊢ ((𝑥 ∈ 𝑧 ∧ 𝑦 ∈ 𝑧) → {𝑥, 𝑦} ⊆ 𝑧) |
| 17 | 15, 16 | impbii 126 |
. . . . . . 7
⊢ ({𝑥, 𝑦} ⊆ 𝑧 ↔ (𝑥 ∈ 𝑧 ∧ 𝑦 ∈ 𝑧)) |
| 18 | 6, 17 | bd0r 15471 |
. . . . . 6
⊢
BOUNDED {𝑥, 𝑦} ⊆ 𝑧 |
| 19 | 3, 18 | ax-bdan 15461 |
. . . . 5
⊢
BOUNDED (𝑧 ⊆ {𝑥, 𝑦} ∧ {𝑥, 𝑦} ⊆ 𝑧) |
| 20 | | eqss 3198 |
. . . . 5
⊢ (𝑧 = {𝑥, 𝑦} ↔ (𝑧 ⊆ {𝑥, 𝑦} ∧ {𝑥, 𝑦} ⊆ 𝑧)) |
| 21 | 19, 20 | bd0r 15471 |
. . . 4
⊢
BOUNDED 𝑧 = {𝑥, 𝑦} |
| 22 | 1, 21 | ax-bdor 15462 |
. . 3
⊢
BOUNDED (𝑧 = {𝑥} ∨ 𝑧 = {𝑥, 𝑦}) |
| 23 | | vex 2766 |
. . . 4
⊢ 𝑧 ∈ V |
| 24 | 23, 7, 11 | elop 4264 |
. . 3
⊢ (𝑧 ∈ 〈𝑥, 𝑦〉 ↔ (𝑧 = {𝑥} ∨ 𝑧 = {𝑥, 𝑦})) |
| 25 | 22, 24 | bd0r 15471 |
. 2
⊢
BOUNDED 𝑧 ∈ 〈𝑥, 𝑦〉 |
| 26 | 25 | bdelir 15493 |
1
⊢
BOUNDED 〈𝑥, 𝑦〉 |