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Theorem unitg 22857
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 22854 . . . . . 6 (π‘₯ ∈ (topGenβ€˜π΅) β†’ π‘₯ βŠ† βˆͺ 𝐡)
2 velpw 4603 . . . . . 6 (π‘₯ ∈ 𝒫 βˆͺ 𝐡 ↔ π‘₯ βŠ† βˆͺ 𝐡)
31, 2sylibr 233 . . . . 5 (π‘₯ ∈ (topGenβ€˜π΅) β†’ π‘₯ ∈ 𝒫 βˆͺ 𝐡)
43ssriv 3982 . . . 4 (topGenβ€˜π΅) βŠ† 𝒫 βˆͺ 𝐡
5 sspwuni 5097 . . . 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 22856 . . 3 (𝐡 ∈ 𝑉 β†’ 𝐡 βŠ† (topGenβ€˜π΅))
98unissd 4913 . 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 1534   ∈ wcel 2099   βŠ† wss 3944  π’« cpw 4598  βˆͺ cuni 4903  β€˜cfv 6542  topGenctg 17410
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1906  ax-6 1964  ax-7 2004  ax-8 2101  ax-9 2109  ax-10 2130  ax-11 2147  ax-12 2164  ax-ext 2698  ax-sep 5293  ax-nul 5300  ax-pow 5359  ax-pr 5423  ax-un 7734
This theorem depends on definitions:  df-bi 206  df-an 396  df-or 847  df-3an 1087  df-tru 1537  df-fal 1547  df-ex 1775  df-nf 1779  df-sb 2061  df-mo 2529  df-eu 2558  df-clab 2705  df-cleq 2719  df-clel 2805  df-nfc 2880  df-ral 3057  df-rex 3066  df-rab 3428  df-v 3471  df-dif 3947  df-un 3949  df-in 3951  df-ss 3961  df-nul 4319  df-if 4525  df-pw 4600  df-sn 4625  df-pr 4627  df-op 4631  df-uni 4904  df-br 5143  df-opab 5205  df-mpt 5226  df-id 5570  df-xp 5678  df-rel 5679  df-cnv 5680  df-co 5681  df-dm 5682  df-iota 6494  df-fun 6544  df-fv 6550  df-topgen 17416
This theorem is referenced by:  tgcl  22859  tgtopon  22861  tgcmp  23292  2ndcsep  23350  txtopon  23482  ptuni  23485  xkouni  23490  prdstopn  23519  tgqtop  23603  alexsubb  23937  alexsubALTlem3  23940  alexsubALTlem4  23941  ptcmplem1  23943  uniretop  24666  fneval  35772  fnemeet1  35786  kelac2  42411
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