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Theorem unitg 22461
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 22458 . . . . . 6 (π‘₯ ∈ (topGenβ€˜π΅) β†’ π‘₯ βŠ† βˆͺ 𝐡)
2 velpw 4606 . . . . . 6 (π‘₯ ∈ 𝒫 βˆͺ 𝐡 ↔ π‘₯ βŠ† βˆͺ 𝐡)
31, 2sylibr 233 . . . . 5 (π‘₯ ∈ (topGenβ€˜π΅) β†’ π‘₯ ∈ 𝒫 βˆͺ 𝐡)
43ssriv 3985 . . . 4 (topGenβ€˜π΅) βŠ† 𝒫 βˆͺ 𝐡
5 sspwuni 5102 . . . 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 22460 . . 3 (𝐡 ∈ 𝑉 β†’ 𝐡 βŠ† (topGenβ€˜π΅))
98unissd 4917 . 2 (𝐡 ∈ 𝑉 β†’ βˆͺ 𝐡 βŠ† βˆͺ (topGenβ€˜π΅))
107, 9eqssd 3998 1 (𝐡 ∈ 𝑉 β†’ βˆͺ (topGenβ€˜π΅) = βˆͺ 𝐡)
Colors of variables: wff setvar class
Syntax hints:   β†’ wi 4   = wceq 1541   ∈ wcel 2106   βŠ† wss 3947  π’« cpw 4601  βˆͺ cuni 4907  β€˜cfv 6540  topGenctg 17379
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  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 2703  ax-sep 5298  ax-nul 5305  ax-pow 5362  ax-pr 5426  ax-un 7721
This theorem depends on definitions:  df-bi 206  df-an 397  df-or 846  df-3an 1089  df-tru 1544  df-fal 1554  df-ex 1782  df-nf 1786  df-sb 2068  df-mo 2534  df-eu 2563  df-clab 2710  df-cleq 2724  df-clel 2810  df-nfc 2885  df-ral 3062  df-rex 3071  df-rab 3433  df-v 3476  df-dif 3950  df-un 3952  df-in 3954  df-ss 3964  df-nul 4322  df-if 4528  df-pw 4603  df-sn 4628  df-pr 4630  df-op 4634  df-uni 4908  df-br 5148  df-opab 5210  df-mpt 5231  df-id 5573  df-xp 5681  df-rel 5682  df-cnv 5683  df-co 5684  df-dm 5685  df-iota 6492  df-fun 6542  df-fv 6548  df-topgen 17385
This theorem is referenced by:  tgcl  22463  tgtopon  22465  tgcmp  22896  2ndcsep  22954  txtopon  23086  ptuni  23089  xkouni  23094  prdstopn  23123  tgqtop  23207  alexsubb  23541  alexsubALTlem3  23544  alexsubALTlem4  23545  ptcmplem1  23547  uniretop  24270  fneval  35225  fnemeet1  35239  kelac2  41792
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