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Theorem ontgval 36392
Description: The topology generated from an ordinal number 𝐵 is suc 𝐵. (Contributed by Chen-Pang He, 10-Oct-2015.)
Assertion
Ref Expression
ontgval (𝐵 ∈ On → (topGen‘𝐵) = suc 𝐵)

Proof of Theorem ontgval
Dummy variable 𝑥 is distinct from all other variables.
StepHypRef Expression
1 eltg4i 22823 . . . . . 6 (𝑥 ∈ (topGen‘𝐵) → 𝑥 = (𝐵 ∩ 𝒫 𝑥))
2 inex1g 5269 . . . . . . 7 (𝐵 ∈ On → (𝐵 ∩ 𝒫 𝑥) ∈ V)
3 onss 7741 . . . . . . . 8 (𝐵 ∈ On → 𝐵 ⊆ On)
4 ssinss1 4205 . . . . . . . 8 (𝐵 ⊆ On → (𝐵 ∩ 𝒫 𝑥) ⊆ On)
53, 4syl 17 . . . . . . 7 (𝐵 ∈ On → (𝐵 ∩ 𝒫 𝑥) ⊆ On)
6 ssonuni 7736 . . . . . . 7 ((𝐵 ∩ 𝒫 𝑥) ∈ V → ((𝐵 ∩ 𝒫 𝑥) ⊆ On → (𝐵 ∩ 𝒫 𝑥) ∈ On))
72, 5, 6sylc 65 . . . . . 6 (𝐵 ∈ On → (𝐵 ∩ 𝒫 𝑥) ∈ On)
8 eleq1 2816 . . . . . . 7 (𝑥 = (𝐵 ∩ 𝒫 𝑥) → (𝑥 ∈ On ↔ (𝐵 ∩ 𝒫 𝑥) ∈ On))
98biimprd 248 . . . . . 6 (𝑥 = (𝐵 ∩ 𝒫 𝑥) → ( (𝐵 ∩ 𝒫 𝑥) ∈ On → 𝑥 ∈ On))
101, 7, 9syl2imc 41 . . . . 5 (𝐵 ∈ On → (𝑥 ∈ (topGen‘𝐵) → 𝑥 ∈ On))
11 onuni 7744 . . . . . 6 (𝐵 ∈ On → 𝐵 ∈ On)
12 onsuc 7767 . . . . . 6 ( 𝐵 ∈ On → suc 𝐵 ∈ On)
1311, 12syl 17 . . . . 5 (𝐵 ∈ On → suc 𝐵 ∈ On)
1410, 13jctird 526 . . . 4 (𝐵 ∈ On → (𝑥 ∈ (topGen‘𝐵) → (𝑥 ∈ On ∧ suc 𝐵 ∈ On)))
15 tg1 22827 . . . . . 6 (𝑥 ∈ (topGen‘𝐵) → 𝑥 𝐵)
1615a1i 11 . . . . 5 (𝐵 ∈ On → (𝑥 ∈ (topGen‘𝐵) → 𝑥 𝐵))
17 sucidg 6403 . . . . . 6 ( 𝐵 ∈ On → 𝐵 ∈ suc 𝐵)
1811, 17syl 17 . . . . 5 (𝐵 ∈ On → 𝐵 ∈ suc 𝐵)
1916, 18jctird 526 . . . 4 (𝐵 ∈ On → (𝑥 ∈ (topGen‘𝐵) → (𝑥 𝐵 𝐵 ∈ suc 𝐵)))
20 ontr2 6368 . . . 4 ((𝑥 ∈ On ∧ suc 𝐵 ∈ On) → ((𝑥 𝐵 𝐵 ∈ suc 𝐵) → 𝑥 ∈ suc 𝐵))
2114, 19, 20syl6c 70 . . 3 (𝐵 ∈ On → (𝑥 ∈ (topGen‘𝐵) → 𝑥 ∈ suc 𝐵))
22 elsuci 6389 . . . 4 (𝑥 ∈ suc 𝐵 → (𝑥 𝐵𝑥 = 𝐵))
23 eloni 6330 . . . . . . . 8 (𝐵 ∈ On → Ord 𝐵)
24 orduniss 6419 . . . . . . . 8 (Ord 𝐵 𝐵𝐵)
2523, 24syl 17 . . . . . . 7 (𝐵 ∈ On → 𝐵𝐵)
26 bastg 22829 . . . . . . 7 (𝐵 ∈ On → 𝐵 ⊆ (topGen‘𝐵))
2725, 26sstrd 3954 . . . . . 6 (𝐵 ∈ On → 𝐵 ⊆ (topGen‘𝐵))
2827sseld 3942 . . . . 5 (𝐵 ∈ On → (𝑥 𝐵𝑥 ∈ (topGen‘𝐵)))
29 ssid 3966 . . . . . . 7 𝐵𝐵
30 eltg3i 22824 . . . . . . 7 ((𝐵 ∈ On ∧ 𝐵𝐵) → 𝐵 ∈ (topGen‘𝐵))
3129, 30mpan2 691 . . . . . 6 (𝐵 ∈ On → 𝐵 ∈ (topGen‘𝐵))
32 eleq1a 2823 . . . . . 6 ( 𝐵 ∈ (topGen‘𝐵) → (𝑥 = 𝐵𝑥 ∈ (topGen‘𝐵)))
3331, 32syl 17 . . . . 5 (𝐵 ∈ On → (𝑥 = 𝐵𝑥 ∈ (topGen‘𝐵)))
3428, 33jaod 859 . . . 4 (𝐵 ∈ On → ((𝑥 𝐵𝑥 = 𝐵) → 𝑥 ∈ (topGen‘𝐵)))
3522, 34syl5 34 . . 3 (𝐵 ∈ On → (𝑥 ∈ suc 𝐵𝑥 ∈ (topGen‘𝐵)))
3621, 35impbid 212 . 2 (𝐵 ∈ On → (𝑥 ∈ (topGen‘𝐵) ↔ 𝑥 ∈ suc 𝐵))
3736eqrdv 2727 1 (𝐵 ∈ On → (topGen‘𝐵) = suc 𝐵)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 395  wo 847   = wceq 1540  wcel 2109  Vcvv 3444  cin 3910  wss 3911  𝒫 cpw 4559   cuni 4867  Ord word 6319  Oncon0 6320  suc csuc 6322  cfv 6499  topGenctg 17376
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-10 2142  ax-11 2158  ax-12 2178  ax-ext 2701  ax-sep 5246  ax-nul 5256  ax-pow 5315  ax-pr 5382  ax-un 7691
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-nf 1784  df-sb 2066  df-mo 2533  df-eu 2562  df-clab 2708  df-cleq 2721  df-clel 2803  df-nfc 2878  df-ne 2926  df-ral 3045  df-rex 3054  df-rab 3403  df-v 3446  df-dif 3914  df-un 3916  df-in 3918  df-ss 3928  df-pss 3931  df-nul 4293  df-if 4485  df-pw 4561  df-sn 4586  df-pr 4588  df-op 4592  df-uni 4868  df-br 5103  df-opab 5165  df-mpt 5184  df-tr 5210  df-id 5526  df-eprel 5531  df-po 5539  df-so 5540  df-fr 5584  df-we 5586  df-xp 5637  df-rel 5638  df-cnv 5639  df-co 5640  df-dm 5641  df-ord 6323  df-on 6324  df-suc 6326  df-iota 6452  df-fun 6501  df-fv 6507  df-topgen 17382
This theorem is referenced by:  ontgsucval  36393
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