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Theorem cmphmph 21961
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 21949 . 2 (𝐽𝐾 ↔ (𝐽Homeo𝐾) ≠ ∅)
2 n0 4159 . . 3 ((𝐽Homeo𝐾) ≠ ∅ ↔ ∃𝑓 𝑓 ∈ (𝐽Homeo𝐾))
3 eqid 2824 . . . . . . 7 𝐽 = 𝐽
4 eqid 2824 . . . . . . 7 𝐾 = 𝐾
53, 4hmeof1o 21937 . . . . . 6 (𝑓 ∈ (𝐽Homeo𝐾) → 𝑓: 𝐽1-1-onto 𝐾)
6 f1ofo 6384 . . . . . 6 (𝑓: 𝐽1-1-onto 𝐾𝑓: 𝐽onto 𝐾)
75, 6syl 17 . . . . 5 (𝑓 ∈ (𝐽Homeo𝐾) → 𝑓: 𝐽onto 𝐾)
8 hmeocn 21933 . . . . 5 (𝑓 ∈ (𝐽Homeo𝐾) → 𝑓 ∈ (𝐽 Cn 𝐾))
94cncmp 21565 . . . . . . 7 ((𝐽 ∈ Comp ∧ 𝑓: 𝐽onto 𝐾𝑓 ∈ (𝐽 Cn 𝐾)) → 𝐾 ∈ Comp)
1093expb 1155 . . . . . 6 ((𝐽 ∈ Comp ∧ (𝑓: 𝐽onto 𝐾𝑓 ∈ (𝐽 Cn 𝐾))) → 𝐾 ∈ Comp)
1110expcom 404 . . . . 5 ((𝑓: 𝐽onto 𝐾𝑓 ∈ (𝐽 Cn 𝐾)) → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
127, 8, 11syl2anc 581 . . . 4 (𝑓 ∈ (𝐽Homeo𝐾) → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
1312exlimiv 2031 . . 3 (∃𝑓 𝑓 ∈ (𝐽Homeo𝐾) → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
142, 13sylbi 209 . 2 ((𝐽Homeo𝐾) ≠ ∅ → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
151, 14sylbi 209 1 (𝐽𝐾 → (𝐽 ∈ Comp → 𝐾 ∈ Comp))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 386  wex 1880  wcel 2166  wne 2998  c0 4143   cuni 4657   class class class wbr 4872  ontowfo 6120  1-1-ontowf1o 6121  (class class class)co 6904   Cn ccn 21398  Compccmp 21559  Homeochmeo 21926  chmph 21927
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1896  ax-4 1910  ax-5 2011  ax-6 2077  ax-7 2114  ax-8 2168  ax-9 2175  ax-10 2194  ax-11 2209  ax-12 2222  ax-13 2390  ax-ext 2802  ax-sep 5004  ax-nul 5012  ax-pow 5064  ax-pr 5126  ax-un 7208
This theorem depends on definitions:  df-bi 199  df-an 387  df-or 881  df-3or 1114  df-3an 1115  df-tru 1662  df-ex 1881  df-nf 1885  df-sb 2070  df-mo 2604  df-eu 2639  df-clab 2811  df-cleq 2817  df-clel 2820  df-nfc 2957  df-ne 2999  df-ral 3121  df-rex 3122  df-reu 3123  df-rab 3125  df-v 3415  df-sbc 3662  df-csb 3757  df-dif 3800  df-un 3802  df-in 3804  df-ss 3811  df-pss 3813  df-nul 4144  df-if 4306  df-pw 4379  df-sn 4397  df-pr 4399  df-tp 4401  df-op 4403  df-uni 4658  df-int 4697  df-iun 4741  df-br 4873  df-opab 4935  df-mpt 4952  df-tr 4975  df-id 5249  df-eprel 5254  df-po 5262  df-so 5263  df-fr 5300  df-we 5302  df-xp 5347  df-rel 5348  df-cnv 5349  df-co 5350  df-dm 5351  df-rn 5352  df-res 5353  df-ima 5354  df-pred 5919  df-ord 5965  df-on 5966  df-lim 5967  df-suc 5968  df-iota 6085  df-fun 6124  df-fn 6125  df-f 6126  df-f1 6127  df-fo 6128  df-f1o 6129  df-fv 6130  df-ov 6907  df-oprab 6908  df-mpt2 6909  df-om 7326  df-1st 7427  df-2nd 7428  df-wrecs 7671  df-recs 7733  df-rdg 7771  df-1o 7825  df-oadd 7829  df-er 8008  df-map 8123  df-en 8222  df-dom 8223  df-fin 8225  df-top 21068  df-topon 21085  df-cn 21401  df-cmp 21560  df-hmeo 21928  df-hmph 21929
This theorem is referenced by:  ptcmpfi  21986  xrcmp  23116  reheibor  34179
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