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Mirrors > Home > MPE Home > Th. List > Mathboxes > gneispace0nelrn2 | Structured version Visualization version GIF version |
Description: A generic neighborhood space has a nonempty set of neighborhoods for every point in its domain. (Contributed by RP, 15-Apr-2021.) |
Ref | Expression |
---|---|
gneispace.a | ⊢ 𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓∀𝑛 ∈ (𝑓‘𝑝)(𝑝 ∈ 𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛 ⊆ 𝑠 → 𝑠 ∈ (𝑓‘𝑝))))} |
Ref | Expression |
---|---|
gneispace0nelrn2 | ⊢ ((𝐹 ∈ 𝐴 ∧ 𝑃 ∈ dom 𝐹) → (𝐹‘𝑃) ≠ ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | gneispace.a | . . . 4 ⊢ 𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓∀𝑛 ∈ (𝑓‘𝑝)(𝑝 ∈ 𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛 ⊆ 𝑠 → 𝑠 ∈ (𝑓‘𝑝))))} | |
2 | 1 | gneispace0nelrn 41731 | . . 3 ⊢ (𝐹 ∈ 𝐴 → ∀𝑝 ∈ dom 𝐹(𝐹‘𝑝) ≠ ∅) |
3 | fveq2 6766 | . . . . 5 ⊢ (𝑝 = 𝑃 → (𝐹‘𝑝) = (𝐹‘𝑃)) | |
4 | 3 | neeq1d 3003 | . . . 4 ⊢ (𝑝 = 𝑃 → ((𝐹‘𝑝) ≠ ∅ ↔ (𝐹‘𝑃) ≠ ∅)) |
5 | 4 | rspccv 3556 | . . 3 ⊢ (∀𝑝 ∈ dom 𝐹(𝐹‘𝑝) ≠ ∅ → (𝑃 ∈ dom 𝐹 → (𝐹‘𝑃) ≠ ∅)) |
6 | 2, 5 | syl 17 | . 2 ⊢ (𝐹 ∈ 𝐴 → (𝑃 ∈ dom 𝐹 → (𝐹‘𝑃) ≠ ∅)) |
7 | 6 | imp 407 | 1 ⊢ ((𝐹 ∈ 𝐴 ∧ 𝑃 ∈ dom 𝐹) → (𝐹‘𝑃) ≠ ∅) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 396 = wceq 1539 ∈ wcel 2106 {cab 2715 ≠ wne 2943 ∀wral 3064 ∖ cdif 3883 ⊆ wss 3886 ∅c0 4256 𝒫 cpw 4533 {csn 4561 dom cdm 5584 ⟶wf 6422 ‘cfv 6426 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2709 ax-sep 5221 ax-nul 5228 ax-pr 5350 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3an 1088 df-tru 1542 df-fal 1552 df-ex 1783 df-nf 1787 df-sb 2068 df-mo 2540 df-eu 2569 df-clab 2716 df-cleq 2730 df-clel 2816 df-nfc 2889 df-ne 2944 df-ral 3069 df-rex 3070 df-rab 3073 df-v 3431 df-dif 3889 df-un 3891 df-in 3893 df-ss 3903 df-nul 4257 df-if 4460 df-pw 4535 df-sn 4562 df-pr 4564 df-op 4568 df-uni 4840 df-br 5074 df-opab 5136 df-mpt 5157 df-id 5484 df-xp 5590 df-rel 5591 df-cnv 5592 df-co 5593 df-dm 5594 df-rn 5595 df-iota 6384 df-fun 6428 df-fn 6429 df-f 6430 df-fv 6434 |
This theorem is referenced by: (None) |
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