| Step | Hyp | Ref
 | Expression | 
| 1 |   | remet.1 | 
. . . . 5
⊢ 𝐷 = ((abs ∘ − )
↾ (ℝ × ℝ)) | 
| 2 | 1 | rexmet 14785 | 
. . . 4
⊢ 𝐷 ∈
(∞Met‘ℝ) | 
| 3 |   | blrn 14648 | 
. . . 4
⊢ (𝐷 ∈
(∞Met‘ℝ) → (𝑧 ∈ ran (ball‘𝐷) ↔ ∃𝑦 ∈ ℝ ∃𝑟 ∈ ℝ* 𝑧 = (𝑦(ball‘𝐷)𝑟))) | 
| 4 | 2, 3 | ax-mp 5 | 
. . 3
⊢ (𝑧 ∈ ran (ball‘𝐷) ↔ ∃𝑦 ∈ ℝ ∃𝑟 ∈ ℝ*
𝑧 = (𝑦(ball‘𝐷)𝑟)) | 
| 5 |   | elxr 9851 | 
. . . . . 6
⊢ (𝑟 ∈ ℝ*
↔ (𝑟 ∈ ℝ
∨ 𝑟 = +∞ ∨
𝑟 =
-∞)) | 
| 6 | 1 | bl2ioo 14786 | 
. . . . . . . 8
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ) → (𝑦(ball‘𝐷)𝑟) = ((𝑦 − 𝑟)(,)(𝑦 + 𝑟))) | 
| 7 |   | resubcl 8290 | 
. . . . . . . . 9
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ) → (𝑦 − 𝑟) ∈ ℝ) | 
| 8 |   | readdcl 8005 | 
. . . . . . . . 9
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ) → (𝑦 + 𝑟) ∈ ℝ) | 
| 9 |   | rexr 8072 | 
. . . . . . . . . 10
⊢ ((𝑦 − 𝑟) ∈ ℝ → (𝑦 − 𝑟) ∈
ℝ*) | 
| 10 |   | rexr 8072 | 
. . . . . . . . . 10
⊢ ((𝑦 + 𝑟) ∈ ℝ → (𝑦 + 𝑟) ∈
ℝ*) | 
| 11 |   | ioorebasg 10050 | 
. . . . . . . . . 10
⊢ (((𝑦 − 𝑟) ∈ ℝ* ∧ (𝑦 + 𝑟) ∈ ℝ*) → ((𝑦 − 𝑟)(,)(𝑦 + 𝑟)) ∈ ran (,)) | 
| 12 | 9, 10, 11 | syl2an 289 | 
. . . . . . . . 9
⊢ (((𝑦 − 𝑟) ∈ ℝ ∧ (𝑦 + 𝑟) ∈ ℝ) → ((𝑦 − 𝑟)(,)(𝑦 + 𝑟)) ∈ ran (,)) | 
| 13 | 7, 8, 12 | syl2anc 411 | 
. . . . . . . 8
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ) → ((𝑦 − 𝑟)(,)(𝑦 + 𝑟)) ∈ ran (,)) | 
| 14 | 6, 13 | eqeltrd 2273 | 
. . . . . . 7
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ) → (𝑦(ball‘𝐷)𝑟) ∈ ran (,)) | 
| 15 |   | oveq2 5930 | 
. . . . . . . . 9
⊢ (𝑟 = +∞ → (𝑦(ball‘𝐷)𝑟) = (𝑦(ball‘𝐷)+∞)) | 
| 16 | 1 | remet 14784 | 
. . . . . . . . . 10
⊢ 𝐷 ∈
(Met‘ℝ) | 
| 17 |   | blpnf 14636 | 
. . . . . . . . . 10
⊢ ((𝐷 ∈ (Met‘ℝ)
∧ 𝑦 ∈ ℝ)
→ (𝑦(ball‘𝐷)+∞) =
ℝ) | 
| 18 | 16, 17 | mpan 424 | 
. . . . . . . . 9
⊢ (𝑦 ∈ ℝ → (𝑦(ball‘𝐷)+∞) = ℝ) | 
| 19 | 15, 18 | sylan9eqr 2251 | 
. . . . . . . 8
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 = +∞) → (𝑦(ball‘𝐷)𝑟) = ℝ) | 
| 20 |   | ioomax 10023 | 
. . . . . . . . 9
⊢
(-∞(,)+∞) = ℝ | 
| 21 |   | mnfxr 8083 | 
. . . . . . . . . 10
⊢ -∞
∈ ℝ* | 
| 22 |   | pnfxr 8079 | 
. . . . . . . . . 10
⊢ +∞
∈ ℝ* | 
| 23 |   | ioorebasg 10050 | 
. . . . . . . . . 10
⊢
((-∞ ∈ ℝ* ∧ +∞ ∈
ℝ*) → (-∞(,)+∞) ∈ ran
(,)) | 
| 24 | 21, 22, 23 | mp2an 426 | 
. . . . . . . . 9
⊢
(-∞(,)+∞) ∈ ran (,) | 
| 25 | 20, 24 | eqeltrri 2270 | 
. . . . . . . 8
⊢ ℝ
∈ ran (,) | 
| 26 | 19, 25 | eqeltrdi 2287 | 
. . . . . . 7
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 = +∞) → (𝑦(ball‘𝐷)𝑟) ∈ ran (,)) | 
| 27 |   | oveq2 5930 | 
. . . . . . . . 9
⊢ (𝑟 = -∞ → (𝑦(ball‘𝐷)𝑟) = (𝑦(ball‘𝐷)-∞)) | 
| 28 |   | 0xr 8073 | 
. . . . . . . . . . . 12
⊢ 0 ∈
ℝ* | 
| 29 |   | nltmnf 9863 | 
. . . . . . . . . . . 12
⊢ (0 ∈
ℝ* → ¬ 0 < -∞) | 
| 30 | 28, 29 | ax-mp 5 | 
. . . . . . . . . . 11
⊢  ¬ 0
< -∞ | 
| 31 |   | xblm 14653 | 
. . . . . . . . . . . 12
⊢ ((𝐷 ∈
(∞Met‘ℝ) ∧ 𝑦 ∈ ℝ ∧ -∞ ∈
ℝ*) → (∃𝑤 𝑤 ∈ (𝑦(ball‘𝐷)-∞) ↔ 0 <
-∞)) | 
| 32 | 2, 21, 31 | mp3an13 1339 | 
. . . . . . . . . . 11
⊢ (𝑦 ∈ ℝ →
(∃𝑤 𝑤 ∈ (𝑦(ball‘𝐷)-∞) ↔ 0 <
-∞)) | 
| 33 | 30, 32 | mtbiri 676 | 
. . . . . . . . . 10
⊢ (𝑦 ∈ ℝ → ¬
∃𝑤 𝑤 ∈ (𝑦(ball‘𝐷)-∞)) | 
| 34 |   | notm0 3471 | 
. . . . . . . . . 10
⊢ (¬
∃𝑤 𝑤 ∈ (𝑦(ball‘𝐷)-∞) ↔ (𝑦(ball‘𝐷)-∞) = ∅) | 
| 35 | 33, 34 | sylib 122 | 
. . . . . . . . 9
⊢ (𝑦 ∈ ℝ → (𝑦(ball‘𝐷)-∞) = ∅) | 
| 36 | 27, 35 | sylan9eqr 2251 | 
. . . . . . . 8
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 = -∞) → (𝑦(ball‘𝐷)𝑟) = ∅) | 
| 37 |   | iooidg 9984 | 
. . . . . . . . . 10
⊢ (0 ∈
ℝ* → (0(,)0) = ∅) | 
| 38 | 28, 37 | ax-mp 5 | 
. . . . . . . . 9
⊢ (0(,)0) =
∅ | 
| 39 |   | ioorebasg 10050 | 
. . . . . . . . . 10
⊢ ((0
∈ ℝ* ∧ 0 ∈ ℝ*) → (0(,)0)
∈ ran (,)) | 
| 40 | 28, 28, 39 | mp2an 426 | 
. . . . . . . . 9
⊢ (0(,)0)
∈ ran (,) | 
| 41 | 38, 40 | eqeltrri 2270 | 
. . . . . . . 8
⊢ ∅
∈ ran (,) | 
| 42 | 36, 41 | eqeltrdi 2287 | 
. . . . . . 7
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 = -∞) → (𝑦(ball‘𝐷)𝑟) ∈ ran (,)) | 
| 43 | 14, 26, 42 | 3jaodan 1317 | 
. . . . . 6
⊢ ((𝑦 ∈ ℝ ∧ (𝑟 ∈ ℝ ∨ 𝑟 = +∞ ∨ 𝑟 = -∞)) → (𝑦(ball‘𝐷)𝑟) ∈ ran (,)) | 
| 44 | 5, 43 | sylan2b 287 | 
. . . . 5
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ*)
→ (𝑦(ball‘𝐷)𝑟) ∈ ran (,)) | 
| 45 |   | eleq1 2259 | 
. . . . 5
⊢ (𝑧 = (𝑦(ball‘𝐷)𝑟) → (𝑧 ∈ ran (,) ↔ (𝑦(ball‘𝐷)𝑟) ∈ ran (,))) | 
| 46 | 44, 45 | syl5ibrcom 157 | 
. . . 4
⊢ ((𝑦 ∈ ℝ ∧ 𝑟 ∈ ℝ*)
→ (𝑧 = (𝑦(ball‘𝐷)𝑟) → 𝑧 ∈ ran (,))) | 
| 47 | 46 | rexlimivv 2620 | 
. . 3
⊢
(∃𝑦 ∈
ℝ ∃𝑟 ∈
ℝ* 𝑧 =
(𝑦(ball‘𝐷)𝑟) → 𝑧 ∈ ran (,)) | 
| 48 | 4, 47 | sylbi 121 | 
. 2
⊢ (𝑧 ∈ ran (ball‘𝐷) → 𝑧 ∈ ran (,)) | 
| 49 | 48 | ssriv 3187 | 
1
⊢ ran
(ball‘𝐷) ⊆ ran
(,) |