| Step | Hyp | Ref
 | Expression | 
| 1 |   | xmeter.1 | 
. . . . 5
⊢  ∼ =
(◡𝐷 “ ℝ) | 
| 2 |   | cnvimass 5032 | 
. . . . 5
⊢ (◡𝐷 “ ℝ) ⊆ dom 𝐷 | 
| 3 | 1, 2 | eqsstri 3215 | 
. . . 4
⊢  ∼
⊆ dom 𝐷 | 
| 4 |   | xmetf 14586 | 
. . . 4
⊢ (𝐷 ∈ (∞Met‘𝑋) → 𝐷:(𝑋 × 𝑋)⟶ℝ*) | 
| 5 | 3, 4 | fssdm 5422 | 
. . 3
⊢ (𝐷 ∈ (∞Met‘𝑋) → ∼ ⊆ (𝑋 × 𝑋)) | 
| 6 |   | relxp 4772 | 
. . 3
⊢ Rel
(𝑋 × 𝑋) | 
| 7 |   | relss 4750 | 
. . 3
⊢ ( ∼
⊆ (𝑋 × 𝑋) → (Rel (𝑋 × 𝑋) → Rel ∼ )) | 
| 8 | 5, 6, 7 | mpisyl 1457 | 
. 2
⊢ (𝐷 ∈ (∞Met‘𝑋) → Rel ∼ ) | 
| 9 | 1 | xmeterval 14671 | 
. . . . 5
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∼ 𝑦 ↔ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋 ∧ (𝑥𝐷𝑦) ∈ ℝ))) | 
| 10 | 9 | biimpa 296 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋 ∧ (𝑥𝐷𝑦) ∈ ℝ)) | 
| 11 | 10 | simp2d 1012 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → 𝑦 ∈ 𝑋) | 
| 12 | 10 | simp1d 1011 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → 𝑥 ∈ 𝑋) | 
| 13 |   | simpl 109 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → 𝐷 ∈ (∞Met‘𝑋)) | 
| 14 |   | xmetsym 14604 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝑥𝐷𝑦) = (𝑦𝐷𝑥)) | 
| 15 | 13, 12, 11, 14 | syl3anc 1249 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → (𝑥𝐷𝑦) = (𝑦𝐷𝑥)) | 
| 16 | 10 | simp3d 1013 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → (𝑥𝐷𝑦) ∈ ℝ) | 
| 17 | 15, 16 | eqeltrrd 2274 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → (𝑦𝐷𝑥) ∈ ℝ) | 
| 18 | 1 | xmeterval 14671 | 
. . . 4
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑦 ∼ 𝑥 ↔ (𝑦 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋 ∧ (𝑦𝐷𝑥) ∈ ℝ))) | 
| 19 | 18 | adantr 276 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → (𝑦 ∼ 𝑥 ↔ (𝑦 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋 ∧ (𝑦𝐷𝑥) ∈ ℝ))) | 
| 20 | 11, 12, 17, 19 | mpbir3and 1182 | 
. 2
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∼ 𝑦) → 𝑦 ∼ 𝑥) | 
| 21 | 12 | adantrr 479 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → 𝑥 ∈ 𝑋) | 
| 22 | 1 | xmeterval 14671 | 
. . . . . 6
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑦 ∼ 𝑧 ↔ (𝑦 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ (𝑦𝐷𝑧) ∈ ℝ))) | 
| 23 | 22 | biimpa 296 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑦 ∼ 𝑧) → (𝑦 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ (𝑦𝐷𝑧) ∈ ℝ)) | 
| 24 | 23 | adantrl 478 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → (𝑦 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ (𝑦𝐷𝑧) ∈ ℝ)) | 
| 25 | 24 | simp2d 1012 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → 𝑧 ∈ 𝑋) | 
| 26 |   | simpl 109 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → 𝐷 ∈ (∞Met‘𝑋)) | 
| 27 | 16 | adantrr 479 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → (𝑥𝐷𝑦) ∈ ℝ) | 
| 28 | 24 | simp3d 1013 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → (𝑦𝐷𝑧) ∈ ℝ) | 
| 29 |   | rexadd 9927 | 
. . . . . 6
⊢ (((𝑥𝐷𝑦) ∈ ℝ ∧ (𝑦𝐷𝑧) ∈ ℝ) → ((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧)) = ((𝑥𝐷𝑦) + (𝑦𝐷𝑧))) | 
| 30 |   | readdcl 8005 | 
. . . . . 6
⊢ (((𝑥𝐷𝑦) ∈ ℝ ∧ (𝑦𝐷𝑧) ∈ ℝ) → ((𝑥𝐷𝑦) + (𝑦𝐷𝑧)) ∈ ℝ) | 
| 31 | 29, 30 | eqeltrd 2273 | 
. . . . 5
⊢ (((𝑥𝐷𝑦) ∈ ℝ ∧ (𝑦𝐷𝑧) ∈ ℝ) → ((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧)) ∈ ℝ) | 
| 32 | 27, 28, 31 | syl2anc 411 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → ((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧)) ∈ ℝ) | 
| 33 | 11 | adantrr 479 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → 𝑦 ∈ 𝑋) | 
| 34 |   | xmettri 14608 | 
. . . . 5
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝑥𝐷𝑧) ≤ ((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧))) | 
| 35 | 26, 21, 25, 33, 34 | syl13anc 1251 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → (𝑥𝐷𝑧) ≤ ((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧))) | 
| 36 |   | xmetlecl 14603 | 
. . . 4
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋) ∧ (((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧)) ∈ ℝ ∧ (𝑥𝐷𝑧) ≤ ((𝑥𝐷𝑦) +𝑒 (𝑦𝐷𝑧)))) → (𝑥𝐷𝑧) ∈ ℝ) | 
| 37 | 26, 21, 25, 32, 35, 36 | syl122anc 1258 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → (𝑥𝐷𝑧) ∈ ℝ) | 
| 38 | 1 | xmeterval 14671 | 
. . . 4
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∼ 𝑧 ↔ (𝑥 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ (𝑥𝐷𝑧) ∈ ℝ))) | 
| 39 | 38 | adantr 276 | 
. . 3
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → (𝑥 ∼ 𝑧 ↔ (𝑥 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ (𝑥𝐷𝑧) ∈ ℝ))) | 
| 40 | 21, 25, 37, 39 | mpbir3and 1182 | 
. 2
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ (𝑥 ∼ 𝑦 ∧ 𝑦 ∼ 𝑧)) → 𝑥 ∼ 𝑧) | 
| 41 |   | xmet0 14599 | 
. . . . . . 7
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∈ 𝑋) → (𝑥𝐷𝑥) = 0) | 
| 42 |   | 0re 8026 | 
. . . . . . 7
⊢ 0 ∈
ℝ | 
| 43 | 41, 42 | eqeltrdi 2287 | 
. . . . . 6
⊢ ((𝐷 ∈ (∞Met‘𝑋) ∧ 𝑥 ∈ 𝑋) → (𝑥𝐷𝑥) ∈ ℝ) | 
| 44 | 43 | ex 115 | 
. . . . 5
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∈ 𝑋 → (𝑥𝐷𝑥) ∈ ℝ)) | 
| 45 | 44 | pm4.71rd 394 | 
. . . 4
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∈ 𝑋 ↔ ((𝑥𝐷𝑥) ∈ ℝ ∧ 𝑥 ∈ 𝑋))) | 
| 46 |   | df-3an 982 | 
. . . . 5
⊢ ((𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋 ∧ (𝑥𝐷𝑥) ∈ ℝ) ↔ ((𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋) ∧ (𝑥𝐷𝑥) ∈ ℝ)) | 
| 47 |   | anidm 396 | 
. . . . . 6
⊢ ((𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋) ↔ 𝑥 ∈ 𝑋) | 
| 48 | 47 | anbi2ci 459 | 
. . . . 5
⊢ (((𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋) ∧ (𝑥𝐷𝑥) ∈ ℝ) ↔ ((𝑥𝐷𝑥) ∈ ℝ ∧ 𝑥 ∈ 𝑋)) | 
| 49 | 46, 48 | bitri 184 | 
. . . 4
⊢ ((𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋 ∧ (𝑥𝐷𝑥) ∈ ℝ) ↔ ((𝑥𝐷𝑥) ∈ ℝ ∧ 𝑥 ∈ 𝑋)) | 
| 50 | 45, 49 | bitr4di 198 | 
. . 3
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∈ 𝑋 ↔ (𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋 ∧ (𝑥𝐷𝑥) ∈ ℝ))) | 
| 51 | 1 | xmeterval 14671 | 
. . 3
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∼ 𝑥 ↔ (𝑥 ∈ 𝑋 ∧ 𝑥 ∈ 𝑋 ∧ (𝑥𝐷𝑥) ∈ ℝ))) | 
| 52 | 50, 51 | bitr4d 191 | 
. 2
⊢ (𝐷 ∈ (∞Met‘𝑋) → (𝑥 ∈ 𝑋 ↔ 𝑥 ∼ 𝑥)) | 
| 53 | 8, 20, 40, 52 | iserd 6618 | 
1
⊢ (𝐷 ∈ (∞Met‘𝑋) → ∼ Er 𝑋) |