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Theorem cmphmph 21496
Description: Compactness is a topological property-that is, for any two homeomorphic topologies, either both are compact or neither is. (Contributed by Jeff Hankins, 30-Jun-2009.) (Revised by Mario Carneiro, 23-Aug-2015.)
Assertion
Ref Expression
cmphmph (𝐽𝐾 → (𝐽 ∈ Comp → 𝐾 ∈ Comp))

Proof of Theorem cmphmph
Dummy variable 𝑓 is distinct from all other variables.
StepHypRef Expression
1 hmph 21484 . 2 (𝐽𝐾 ↔ (𝐽Homeo𝐾) ≠ ∅)
2 n0 3912 . . 3 ((𝐽Homeo𝐾) ≠ ∅ ↔ ∃𝑓 𝑓 ∈ (𝐽Homeo𝐾))
3 eqid 2626 . . . . . . 7 𝐽 = 𝐽
4 eqid 2626 . . . . . . 7 𝐾 = 𝐾
53, 4hmeof1o 21472 . . . . . 6 (𝑓 ∈ (𝐽Homeo𝐾) → 𝑓: 𝐽1-1-onto 𝐾)
6 f1ofo 6103 . . . . . 6 (𝑓: 𝐽1-1-onto 𝐾𝑓: 𝐽onto 𝐾)
75, 6syl 17 . . . . 5 (𝑓 ∈ (𝐽Homeo𝐾) → 𝑓: 𝐽onto 𝐾)
8 hmeocn 21468 . . . . 5 (𝑓 ∈ (𝐽Homeo𝐾) → 𝑓 ∈ (𝐽 Cn 𝐾))
94cncmp 21100 . . . . . . 7 ((𝐽 ∈ Comp ∧ 𝑓: 𝐽onto 𝐾𝑓 ∈ (𝐽 Cn 𝐾)) → 𝐾 ∈ Comp)
1093expb 1263 . . . . . 6 ((𝐽 ∈ Comp ∧ (𝑓: 𝐽onto 𝐾𝑓 ∈ (𝐽 Cn 𝐾))) → 𝐾 ∈ Comp)
1110expcom 451 . . . . 5 ((𝑓: 𝐽onto 𝐾𝑓 ∈ (𝐽 Cn 𝐾)) → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
127, 8, 11syl2anc 692 . . . 4 (𝑓 ∈ (𝐽Homeo𝐾) → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
1312exlimiv 1860 . . 3 (∃𝑓 𝑓 ∈ (𝐽Homeo𝐾) → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
142, 13sylbi 207 . 2 ((𝐽Homeo𝐾) ≠ ∅ → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
151, 14sylbi 207 1 (𝐽𝐾 → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 384  wex 1701  wcel 1992  wne 2796  c0 3896   cuni 4407   class class class wbr 4618  ontowfo 5848  1-1-ontowf1o 5849  (class class class)co 6605   Cn ccn 20933  Compccmp 21094  Homeochmeo 21461  chmph 21462
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1841  ax-6 1890  ax-7 1937  ax-8 1994  ax-9 2001  ax-10 2021  ax-11 2036  ax-12 2049  ax-13 2250  ax-ext 2606  ax-sep 4746  ax-nul 4754  ax-pow 4808  ax-pr 4872  ax-un 6903
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1037  df-3an 1038  df-tru 1483  df-ex 1702  df-nf 1707  df-sb 1883  df-eu 2478  df-mo 2479  df-clab 2613  df-cleq 2619  df-clel 2622  df-nfc 2756  df-ne 2797  df-ral 2917  df-rex 2918  df-reu 2919  df-rab 2921  df-v 3193  df-sbc 3423  df-csb 3520  df-dif 3563  df-un 3565  df-in 3567  df-ss 3574  df-pss 3576  df-nul 3897  df-if 4064  df-pw 4137  df-sn 4154  df-pr 4156  df-tp 4158  df-op 4160  df-uni 4408  df-int 4446  df-iun 4492  df-br 4619  df-opab 4679  df-mpt 4680  df-tr 4718  df-eprel 4990  df-id 4994  df-po 5000  df-so 5001  df-fr 5038  df-we 5040  df-xp 5085  df-rel 5086  df-cnv 5087  df-co 5088  df-dm 5089  df-rn 5090  df-res 5091  df-ima 5092  df-pred 5642  df-ord 5688  df-on 5689  df-lim 5690  df-suc 5691  df-iota 5813  df-fun 5852  df-fn 5853  df-f 5854  df-f1 5855  df-fo 5856  df-f1o 5857  df-fv 5858  df-ov 6608  df-oprab 6609  df-mpt2 6610  df-om 7014  df-1st 7116  df-2nd 7117  df-wrecs 7353  df-recs 7414  df-rdg 7452  df-1o 7506  df-oadd 7510  df-er 7688  df-map 7805  df-en 7901  df-dom 7902  df-fin 7904  df-top 20616  df-topon 20618  df-cn 20936  df-cmp 21095  df-hmeo 21463  df-hmph 21464
This theorem is referenced by:  ptcmpfi  21521  xrcmp  22650  reheibor  33256
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