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Theorem unitg 22470
Description: The topology generated by a basis 𝐡 is a topology on βˆͺ 𝐡. Importantly, this theorem means that we don't have to specify separately the base set for the topological space generated by a basis. In other words, any member of the class TopBases completely specifies the basis it corresponds to. (Contributed by NM, 16-Jul-2006.) (Proof shortened by OpenAI, 30-Mar-2020.)
Assertion
Ref Expression
unitg (𝐡 ∈ 𝑉 β†’ βˆͺ (topGenβ€˜π΅) = βˆͺ 𝐡)

Proof of Theorem unitg
Dummy variable π‘₯ is distinct from all other variables.
StepHypRef Expression
1 tg1 22467 . . . . . 6 (π‘₯ ∈ (topGenβ€˜π΅) β†’ π‘₯ βŠ† βˆͺ 𝐡)
2 velpw 4608 . . . . . 6 (π‘₯ ∈ 𝒫 βˆͺ 𝐡 ↔ π‘₯ βŠ† βˆͺ 𝐡)
31, 2sylibr 233 . . . . 5 (π‘₯ ∈ (topGenβ€˜π΅) β†’ π‘₯ ∈ 𝒫 βˆͺ 𝐡)
43ssriv 3987 . . . 4 (topGenβ€˜π΅) βŠ† 𝒫 βˆͺ 𝐡
5 sspwuni 5104 . . . 4 ((topGenβ€˜π΅) βŠ† 𝒫 βˆͺ 𝐡 ↔ βˆͺ (topGenβ€˜π΅) βŠ† βˆͺ 𝐡)
64, 5mpbi 229 . . 3 βˆͺ (topGenβ€˜π΅) βŠ† βˆͺ 𝐡
76a1i 11 . 2 (𝐡 ∈ 𝑉 β†’ βˆͺ (topGenβ€˜π΅) βŠ† βˆͺ 𝐡)
8 bastg 22469 . . 3 (𝐡 ∈ 𝑉 β†’ 𝐡 βŠ† (topGenβ€˜π΅))
98unissd 4919 . 2 (𝐡 ∈ 𝑉 β†’ βˆͺ 𝐡 βŠ† βˆͺ (topGenβ€˜π΅))
107, 9eqssd 4000 1 (𝐡 ∈ 𝑉 β†’ βˆͺ (topGenβ€˜π΅) = βˆͺ 𝐡)
Colors of variables: wff setvar class
Syntax hints:   β†’ wi 4   = wceq 1542   ∈ wcel 2107   βŠ† wss 3949  π’« cpw 4603  βˆͺ cuni 4909  β€˜cfv 6544  topGenctg 17383
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 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2155  ax-12 2172  ax-ext 2704  ax-sep 5300  ax-nul 5307  ax-pow 5364  ax-pr 5428  ax-un 7725
This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-nf 1787  df-sb 2069  df-mo 2535  df-eu 2564  df-clab 2711  df-cleq 2725  df-clel 2811  df-nfc 2886  df-ral 3063  df-rex 3072  df-rab 3434  df-v 3477  df-dif 3952  df-un 3954  df-in 3956  df-ss 3966  df-nul 4324  df-if 4530  df-pw 4605  df-sn 4630  df-pr 4632  df-op 4636  df-uni 4910  df-br 5150  df-opab 5212  df-mpt 5233  df-id 5575  df-xp 5683  df-rel 5684  df-cnv 5685  df-co 5686  df-dm 5687  df-iota 6496  df-fun 6546  df-fv 6552  df-topgen 17389
This theorem is referenced by:  tgcl  22472  tgtopon  22474  tgcmp  22905  2ndcsep  22963  txtopon  23095  ptuni  23098  xkouni  23103  prdstopn  23132  tgqtop  23216  alexsubb  23550  alexsubALTlem3  23553  alexsubALTlem4  23554  ptcmplem1  23556  uniretop  24279  fneval  35237  fnemeet1  35251  kelac2  41807
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