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Theorem unitg 22900
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 22897 . . . . . 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 3981 . . . 4 (topGenβ€˜π΅) βŠ† 𝒫 βˆͺ 𝐡
5 sspwuni 5103 . . . 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 22899 . . 3 (𝐡 ∈ 𝑉 β†’ 𝐡 βŠ† (topGenβ€˜π΅))
98unissd 4918 . 2 (𝐡 ∈ 𝑉 β†’ βˆͺ 𝐡 βŠ† βˆͺ (topGenβ€˜π΅))
107, 9eqssd 3995 1 (𝐡 ∈ 𝑉 β†’ βˆͺ (topGenβ€˜π΅) = βˆͺ 𝐡)
Colors of variables: wff setvar class
Syntax hints:   β†’ wi 4   = wceq 1533   ∈ wcel 2098   βŠ† wss 3945  π’« cpw 4603  βˆͺ cuni 4908  β€˜cfv 6547  topGenctg 17418
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-10 2129  ax-11 2146  ax-12 2166  ax-ext 2696  ax-sep 5299  ax-nul 5306  ax-pow 5364  ax-pr 5428  ax-un 7739
This theorem depends on definitions:  df-bi 206  df-an 395  df-or 846  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-nf 1778  df-sb 2060  df-mo 2528  df-eu 2557  df-clab 2703  df-cleq 2717  df-clel 2802  df-nfc 2877  df-ral 3052  df-rex 3061  df-rab 3420  df-v 3465  df-dif 3948  df-un 3950  df-in 3952  df-ss 3962  df-nul 4324  df-if 4530  df-pw 4605  df-sn 4630  df-pr 4632  df-op 4636  df-uni 4909  df-br 5149  df-opab 5211  df-mpt 5232  df-id 5575  df-xp 5683  df-rel 5684  df-cnv 5685  df-co 5686  df-dm 5687  df-iota 6499  df-fun 6549  df-fv 6555  df-topgen 17424
This theorem is referenced by:  tgcl  22902  tgtopon  22904  tgcmp  23335  2ndcsep  23393  txtopon  23525  ptuni  23528  xkouni  23533  prdstopn  23562  tgqtop  23646  alexsubb  23980  alexsubALTlem3  23983  alexsubALTlem4  23984  ptcmplem1  23986  uniretop  24709  fneval  35906  fnemeet1  35920  kelac2  42554
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