| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | simp1 1136 | . . . . 5
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) → 𝑀 ∈ (∞Met‘𝑋)) | 
| 2 |  | rexr 11308 | . . . . . 6
⊢ (𝑅 ∈ ℝ → 𝑅 ∈
ℝ*) | 
| 3 |  | blssm 24429 | . . . . . 6
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ*) → (𝑌(ball‘𝑀)𝑅) ⊆ 𝑋) | 
| 4 | 2, 3 | syl3an3 1165 | . . . . 5
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) → (𝑌(ball‘𝑀)𝑅) ⊆ 𝑋) | 
| 5 |  | xmetres2 24372 | . . . . 5
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ (𝑌(ball‘𝑀)𝑅) ⊆ 𝑋) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (∞Met‘(𝑌(ball‘𝑀)𝑅))) | 
| 6 | 1, 4, 5 | syl2anc 584 | . . . 4
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (∞Met‘(𝑌(ball‘𝑀)𝑅))) | 
| 7 | 6 | adantr 480 | . . 3
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) = ∅) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (∞Met‘(𝑌(ball‘𝑀)𝑅))) | 
| 8 |  | rzal 4508 | . . . 4
⊢ ((𝑌(ball‘𝑀)𝑅) = ∅ → ∀𝑥 ∈ (𝑌(ball‘𝑀)𝑅)∃𝑟 ∈ ℝ+ (𝑌(ball‘𝑀)𝑅) = (𝑥(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑟)) | 
| 9 | 8 | adantl 481 | . . 3
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) = ∅) → ∀𝑥 ∈ (𝑌(ball‘𝑀)𝑅)∃𝑟 ∈ ℝ+ (𝑌(ball‘𝑀)𝑅) = (𝑥(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑟)) | 
| 10 |  | isbndx 37790 | . . 3
⊢ ((𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (Bnd‘(𝑌(ball‘𝑀)𝑅)) ↔ ((𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (∞Met‘(𝑌(ball‘𝑀)𝑅)) ∧ ∀𝑥 ∈ (𝑌(ball‘𝑀)𝑅)∃𝑟 ∈ ℝ+ (𝑌(ball‘𝑀)𝑅) = (𝑥(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑟))) | 
| 11 | 7, 9, 10 | sylanbrc 583 | . 2
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) = ∅) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (Bnd‘(𝑌(ball‘𝑀)𝑅))) | 
| 12 | 6 | adantr 480 | . . . 4
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (∞Met‘(𝑌(ball‘𝑀)𝑅))) | 
| 13 | 1 | adantr 480 | . . . . . 6
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑀 ∈ (∞Met‘𝑋)) | 
| 14 |  | simpl2 1192 | . . . . . 6
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑌 ∈ 𝑋) | 
| 15 |  | simpl3 1193 | . . . . . . 7
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑅 ∈ ℝ) | 
| 16 |  | xbln0 24425 | . . . . . . . . 9
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ*) → ((𝑌(ball‘𝑀)𝑅) ≠ ∅ ↔ 0 < 𝑅)) | 
| 17 | 2, 16 | syl3an3 1165 | . . . . . . . 8
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) → ((𝑌(ball‘𝑀)𝑅) ≠ ∅ ↔ 0 < 𝑅)) | 
| 18 | 17 | biimpa 476 | . . . . . . 7
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 0 < 𝑅) | 
| 19 | 15, 18 | elrpd 13075 | . . . . . 6
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑅 ∈
ℝ+) | 
| 20 |  | blcntr 24424 | . . . . . 6
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ+) → 𝑌 ∈ (𝑌(ball‘𝑀)𝑅)) | 
| 21 | 13, 14, 19, 20 | syl3anc 1372 | . . . . 5
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑌 ∈ (𝑌(ball‘𝑀)𝑅)) | 
| 22 | 14, 21 | elind 4199 | . . . . . . 7
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑌 ∈ (𝑋 ∩ (𝑌(ball‘𝑀)𝑅))) | 
| 23 | 15 | rexrd 11312 | . . . . . . 7
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → 𝑅 ∈
ℝ*) | 
| 24 |  | eqid 2736 | . . . . . . . 8
⊢ (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) = (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) | 
| 25 | 24 | blres 24442 | . . . . . . 7
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ (𝑋 ∩ (𝑌(ball‘𝑀)𝑅)) ∧ 𝑅 ∈ ℝ*) → (𝑌(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑅) = ((𝑌(ball‘𝑀)𝑅) ∩ (𝑌(ball‘𝑀)𝑅))) | 
| 26 | 13, 22, 23, 25 | syl3anc 1372 | . . . . . 6
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → (𝑌(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑅) = ((𝑌(ball‘𝑀)𝑅) ∩ (𝑌(ball‘𝑀)𝑅))) | 
| 27 |  | inidm 4226 | . . . . . 6
⊢ ((𝑌(ball‘𝑀)𝑅) ∩ (𝑌(ball‘𝑀)𝑅)) = (𝑌(ball‘𝑀)𝑅) | 
| 28 | 26, 27 | eqtr2di 2793 | . . . . 5
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → (𝑌(ball‘𝑀)𝑅) = (𝑌(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑅)) | 
| 29 |  | rspceov 7481 | . . . . 5
⊢ ((𝑌 ∈ (𝑌(ball‘𝑀)𝑅) ∧ 𝑅 ∈ ℝ+ ∧ (𝑌(ball‘𝑀)𝑅) = (𝑌(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑅)) → ∃𝑥 ∈ (𝑌(ball‘𝑀)𝑅)∃𝑟 ∈ ℝ+ (𝑌(ball‘𝑀)𝑅) = (𝑥(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑟)) | 
| 30 | 21, 19, 28, 29 | syl3anc 1372 | . . . 4
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → ∃𝑥 ∈ (𝑌(ball‘𝑀)𝑅)∃𝑟 ∈ ℝ+ (𝑌(ball‘𝑀)𝑅) = (𝑥(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑟)) | 
| 31 |  | isbnd2 37791 | . . . 4
⊢ (((𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (Bnd‘(𝑌(ball‘𝑀)𝑅)) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) ↔ ((𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (∞Met‘(𝑌(ball‘𝑀)𝑅)) ∧ ∃𝑥 ∈ (𝑌(ball‘𝑀)𝑅)∃𝑟 ∈ ℝ+ (𝑌(ball‘𝑀)𝑅) = (𝑥(ball‘(𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))))𝑟))) | 
| 32 | 12, 30, 31 | sylanbrc 583 | . . 3
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → ((𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (Bnd‘(𝑌(ball‘𝑀)𝑅)) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅)) | 
| 33 | 32 | simpld 494 | . 2
⊢ (((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) ∧ (𝑌(ball‘𝑀)𝑅) ≠ ∅) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (Bnd‘(𝑌(ball‘𝑀)𝑅))) | 
| 34 | 11, 33 | pm2.61dane 3028 | 1
⊢ ((𝑀 ∈ (∞Met‘𝑋) ∧ 𝑌 ∈ 𝑋 ∧ 𝑅 ∈ ℝ) → (𝑀 ↾ ((𝑌(ball‘𝑀)𝑅) × (𝑌(ball‘𝑀)𝑅))) ∈ (Bnd‘(𝑌(ball‘𝑀)𝑅))) |