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Mirrors > Home > MPE Home > Th. List > fibas | Structured version Visualization version GIF version |
Description: A collection of finite intersections is a basis. The initial set is a subbasis for the topology. (Contributed by Jeff Hankins, 25-Aug-2009.) (Revised by Mario Carneiro, 24-Nov-2013.) |
Ref | Expression |
---|---|
fibas | ⊢ (fi‘𝐴) ∈ TopBases |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fvex 6920 | . 2 ⊢ (fi‘𝐴) ∈ V | |
2 | fiin 9460 | . . 3 ⊢ ((𝑥 ∈ (fi‘𝐴) ∧ 𝑦 ∈ (fi‘𝐴)) → (𝑥 ∩ 𝑦) ∈ (fi‘𝐴)) | |
3 | 2 | rgen2 3197 | . 2 ⊢ ∀𝑥 ∈ (fi‘𝐴)∀𝑦 ∈ (fi‘𝐴)(𝑥 ∩ 𝑦) ∈ (fi‘𝐴) |
4 | fiinbas 22975 | . 2 ⊢ (((fi‘𝐴) ∈ V ∧ ∀𝑥 ∈ (fi‘𝐴)∀𝑦 ∈ (fi‘𝐴)(𝑥 ∩ 𝑦) ∈ (fi‘𝐴)) → (fi‘𝐴) ∈ TopBases) | |
5 | 1, 3, 4 | mp2an 692 | 1 ⊢ (fi‘𝐴) ∈ TopBases |
Colors of variables: wff setvar class |
Syntax hints: ∈ wcel 2106 ∀wral 3059 Vcvv 3478 ∩ cin 3962 ‘cfv 6563 ficfi 9448 TopBasesctb 22968 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-10 2139 ax-11 2155 ax-12 2175 ax-ext 2706 ax-sep 5302 ax-nul 5312 ax-pow 5371 ax-pr 5438 ax-un 7754 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1540 df-fal 1550 df-ex 1777 df-nf 1781 df-sb 2063 df-mo 2538 df-eu 2567 df-clab 2713 df-cleq 2727 df-clel 2814 df-nfc 2890 df-ne 2939 df-ral 3060 df-rex 3069 df-reu 3379 df-rab 3434 df-v 3480 df-sbc 3792 df-dif 3966 df-un 3968 df-in 3970 df-ss 3980 df-pss 3983 df-nul 4340 df-if 4532 df-pw 4607 df-sn 4632 df-pr 4634 df-op 4638 df-uni 4913 df-int 4952 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5583 df-eprel 5589 df-po 5597 df-so 5598 df-fr 5641 df-we 5643 df-xp 5695 df-rel 5696 df-cnv 5697 df-co 5698 df-dm 5699 df-rn 5700 df-res 5701 df-ima 5702 df-ord 6389 df-on 6390 df-lim 6391 df-suc 6392 df-iota 6516 df-fun 6565 df-fn 6566 df-f 6567 df-f1 6568 df-fo 6569 df-f1o 6570 df-fv 6571 df-om 7888 df-en 8985 df-fin 8988 df-fi 9449 df-bases 22969 |
This theorem is referenced by: restbas 23182 ordttopon 23217 ordtopn1 23218 ordtopn2 23219 ordtrest2 23228 leordtval2 23236 2ndcsb 23473 ptbas 23603 xkotop 23612 alexsublem 24068 alexsub 24069 alexsubb 24070 alexsubALTlem3 24073 alexsubALTlem4 24074 alexsubALT 24075 ptcmplem1 24076 ordtrest2NEW 33884 topjoin 36348 |
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