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Mirrors > Home > ILE Home > Th. List > restdis | GIF version |
Description: A subspace of a discrete topology is discrete. (Contributed by Mario Carneiro, 19-Mar-2015.) |
Ref | Expression |
---|---|
restdis | ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝒫 𝐴 ↾t 𝐵) = 𝒫 𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | distop 12181 | . . . . 5 ⊢ (𝐴 ∈ 𝑉 → 𝒫 𝐴 ∈ Top) | |
2 | 1 | adantr 274 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → 𝒫 𝐴 ∈ Top) |
3 | elpw2g 4051 | . . . . 5 ⊢ (𝐴 ∈ 𝑉 → (𝐵 ∈ 𝒫 𝐴 ↔ 𝐵 ⊆ 𝐴)) | |
4 | 3 | biimpar 295 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → 𝐵 ∈ 𝒫 𝐴) |
5 | restopn2 12279 | . . . 4 ⊢ ((𝒫 𝐴 ∈ Top ∧ 𝐵 ∈ 𝒫 𝐴) → (𝑥 ∈ (𝒫 𝐴 ↾t 𝐵) ↔ (𝑥 ∈ 𝒫 𝐴 ∧ 𝑥 ⊆ 𝐵))) | |
6 | 2, 4, 5 | syl2anc 408 | . . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝑥 ∈ (𝒫 𝐴 ↾t 𝐵) ↔ (𝑥 ∈ 𝒫 𝐴 ∧ 𝑥 ⊆ 𝐵))) |
7 | velpw 3487 | . . . 4 ⊢ (𝑥 ∈ 𝒫 𝐵 ↔ 𝑥 ⊆ 𝐵) | |
8 | sstr 3075 | . . . . . . . 8 ⊢ ((𝑥 ⊆ 𝐵 ∧ 𝐵 ⊆ 𝐴) → 𝑥 ⊆ 𝐴) | |
9 | 8 | expcom 115 | . . . . . . 7 ⊢ (𝐵 ⊆ 𝐴 → (𝑥 ⊆ 𝐵 → 𝑥 ⊆ 𝐴)) |
10 | 9 | adantl 275 | . . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝑥 ⊆ 𝐵 → 𝑥 ⊆ 𝐴)) |
11 | velpw 3487 | . . . . . 6 ⊢ (𝑥 ∈ 𝒫 𝐴 ↔ 𝑥 ⊆ 𝐴) | |
12 | 10, 11 | syl6ibr 161 | . . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝑥 ⊆ 𝐵 → 𝑥 ∈ 𝒫 𝐴)) |
13 | 12 | pm4.71rd 391 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝑥 ⊆ 𝐵 ↔ (𝑥 ∈ 𝒫 𝐴 ∧ 𝑥 ⊆ 𝐵))) |
14 | 7, 13 | syl5bb 191 | . . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝑥 ∈ 𝒫 𝐵 ↔ (𝑥 ∈ 𝒫 𝐴 ∧ 𝑥 ⊆ 𝐵))) |
15 | 6, 14 | bitr4d 190 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝑥 ∈ (𝒫 𝐴 ↾t 𝐵) ↔ 𝑥 ∈ 𝒫 𝐵)) |
16 | 15 | eqrdv 2115 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ⊆ 𝐴) → (𝒫 𝐴 ↾t 𝐵) = 𝒫 𝐵) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 = wceq 1316 ∈ wcel 1465 ⊆ wss 3041 𝒫 cpw 3480 (class class class)co 5742 ↾t crest 12047 Topctop 12091 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 588 ax-in2 589 ax-io 683 ax-5 1408 ax-7 1409 ax-gen 1410 ax-ie1 1454 ax-ie2 1455 ax-8 1467 ax-10 1468 ax-11 1469 ax-i12 1470 ax-bndl 1471 ax-4 1472 ax-13 1476 ax-14 1477 ax-17 1491 ax-i9 1495 ax-ial 1499 ax-i5r 1500 ax-ext 2099 ax-coll 4013 ax-sep 4016 ax-pow 4068 ax-pr 4101 ax-un 4325 ax-setind 4422 |
This theorem depends on definitions: df-bi 116 df-3an 949 df-tru 1319 df-fal 1322 df-nf 1422 df-sb 1721 df-eu 1980 df-mo 1981 df-clab 2104 df-cleq 2110 df-clel 2113 df-nfc 2247 df-ne 2286 df-ral 2398 df-rex 2399 df-reu 2400 df-rab 2402 df-v 2662 df-sbc 2883 df-csb 2976 df-dif 3043 df-un 3045 df-in 3047 df-ss 3054 df-pw 3482 df-sn 3503 df-pr 3504 df-op 3506 df-uni 3707 df-iun 3785 df-br 3900 df-opab 3960 df-mpt 3961 df-id 4185 df-xp 4515 df-rel 4516 df-cnv 4517 df-co 4518 df-dm 4519 df-rn 4520 df-res 4521 df-ima 4522 df-iota 5058 df-fun 5095 df-fn 5096 df-f 5097 df-f1 5098 df-fo 5099 df-f1o 5100 df-fv 5101 df-ov 5745 df-oprab 5746 df-mpo 5747 df-1st 6006 df-2nd 6007 df-rest 12049 df-topgen 12068 df-top 12092 df-topon 12105 df-bases 12137 |
This theorem is referenced by: (None) |
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