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Mirrors > Home > ILE Home > Th. List > tpnei | GIF version |
Description: The underlying set of a topology is a neighborhood of any of its subsets. Special case of opnneiss 13819. (Contributed by FL, 2-Oct-2006.) |
Ref | Expression |
---|---|
tpnei.1 | ⊢ 𝑋 = ∪ 𝐽 |
Ref | Expression |
---|---|
tpnei | ⊢ (𝐽 ∈ Top → (𝑆 ⊆ 𝑋 ↔ 𝑋 ∈ ((nei‘𝐽)‘𝑆))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tpnei.1 | . . . 4 ⊢ 𝑋 = ∪ 𝐽 | |
2 | 1 | topopn 13669 | . . 3 ⊢ (𝐽 ∈ Top → 𝑋 ∈ 𝐽) |
3 | opnneiss 13819 | . . . 4 ⊢ ((𝐽 ∈ Top ∧ 𝑋 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑋) → 𝑋 ∈ ((nei‘𝐽)‘𝑆)) | |
4 | 3 | 3exp 1202 | . . 3 ⊢ (𝐽 ∈ Top → (𝑋 ∈ 𝐽 → (𝑆 ⊆ 𝑋 → 𝑋 ∈ ((nei‘𝐽)‘𝑆)))) |
5 | 2, 4 | mpd 13 | . 2 ⊢ (𝐽 ∈ Top → (𝑆 ⊆ 𝑋 → 𝑋 ∈ ((nei‘𝐽)‘𝑆))) |
6 | ssnei 13812 | . . 3 ⊢ ((𝐽 ∈ Top ∧ 𝑋 ∈ ((nei‘𝐽)‘𝑆)) → 𝑆 ⊆ 𝑋) | |
7 | 6 | ex 115 | . 2 ⊢ (𝐽 ∈ Top → (𝑋 ∈ ((nei‘𝐽)‘𝑆) → 𝑆 ⊆ 𝑋)) |
8 | 5, 7 | impbid 129 | 1 ⊢ (𝐽 ∈ Top → (𝑆 ⊆ 𝑋 ↔ 𝑋 ∈ ((nei‘𝐽)‘𝑆))) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 105 = wceq 1353 ∈ wcel 2148 ⊆ wss 3131 ∪ cuni 3811 ‘cfv 5218 Topctop 13658 neicnei 13799 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 709 ax-5 1447 ax-7 1448 ax-gen 1449 ax-ie1 1493 ax-ie2 1494 ax-8 1504 ax-10 1505 ax-11 1506 ax-i12 1507 ax-bndl 1509 ax-4 1510 ax-17 1526 ax-i9 1530 ax-ial 1534 ax-i5r 1535 ax-14 2151 ax-ext 2159 ax-coll 4120 ax-sep 4123 ax-pow 4176 ax-pr 4211 |
This theorem depends on definitions: df-bi 117 df-3an 980 df-tru 1356 df-nf 1461 df-sb 1763 df-eu 2029 df-mo 2030 df-clab 2164 df-cleq 2170 df-clel 2173 df-nfc 2308 df-ral 2460 df-rex 2461 df-reu 2462 df-rab 2464 df-v 2741 df-sbc 2965 df-csb 3060 df-un 3135 df-in 3137 df-ss 3144 df-pw 3579 df-sn 3600 df-pr 3601 df-op 3603 df-uni 3812 df-iun 3890 df-br 4006 df-opab 4067 df-mpt 4068 df-id 4295 df-xp 4634 df-rel 4635 df-cnv 4636 df-co 4637 df-dm 4638 df-rn 4639 df-res 4640 df-ima 4641 df-iota 5180 df-fun 5220 df-fn 5221 df-f 5222 df-f1 5223 df-fo 5224 df-f1o 5225 df-fv 5226 df-top 13659 df-nei 13800 |
This theorem is referenced by: neiuni 13822 |
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