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Theorem cfle 10248
Description: Cofinality is bounded by its argument. Exercise 1 of [TakeutiZaring] p. 102. (Contributed by NM, 26-Apr-2004.) (Revised by Mario Carneiro, 15-Sep-2013.)
Assertion
Ref Expression
cfle (cfβ€˜π΄) βŠ† 𝐴

Proof of Theorem cfle
StepHypRef Expression
1 cflecard 10247 . . 3 (cfβ€˜π΄) βŠ† (cardβ€˜π΄)
2 cardonle 9951 . . 3 (𝐴 ∈ On β†’ (cardβ€˜π΄) βŠ† 𝐴)
31, 2sstrid 3993 . 2 (𝐴 ∈ On β†’ (cfβ€˜π΄) βŠ† 𝐴)
4 cff 10242 . . . . . 6 cf:On⟢On
54fdmi 6729 . . . . 5 dom cf = On
65eleq2i 2825 . . . 4 (𝐴 ∈ dom cf ↔ 𝐴 ∈ On)
7 ndmfv 6926 . . . 4 (Β¬ 𝐴 ∈ dom cf β†’ (cfβ€˜π΄) = βˆ…)
86, 7sylnbir 330 . . 3 (Β¬ 𝐴 ∈ On β†’ (cfβ€˜π΄) = βˆ…)
9 0ss 4396 . . 3 βˆ… βŠ† 𝐴
108, 9eqsstrdi 4036 . 2 (Β¬ 𝐴 ∈ On β†’ (cfβ€˜π΄) βŠ† 𝐴)
113, 10pm2.61i 182 1 (cfβ€˜π΄) βŠ† 𝐴
Colors of variables: wff setvar class
Syntax hints:  Β¬ wn 3   = wceq 1541   ∈ wcel 2106   βŠ† wss 3948  βˆ…c0 4322  dom cdm 5676  Oncon0 6364  β€˜cfv 6543  cardccrd 9929  cfccf 9931
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1913  ax-6 1971  ax-7 2011  ax-8 2108  ax-9 2116  ax-10 2137  ax-11 2154  ax-12 2171  ax-ext 2703  ax-sep 5299  ax-nul 5306  ax-pow 5363  ax-pr 5427  ax-un 7724
This theorem depends on definitions:  df-bi 206  df-an 397  df-or 846  df-3or 1088  df-3an 1089  df-tru 1544  df-fal 1554  df-ex 1782  df-nf 1786  df-sb 2068  df-mo 2534  df-eu 2563  df-clab 2710  df-cleq 2724  df-clel 2810  df-nfc 2885  df-ne 2941  df-ral 3062  df-rex 3071  df-rab 3433  df-v 3476  df-dif 3951  df-un 3953  df-in 3955  df-ss 3965  df-pss 3967  df-nul 4323  df-if 4529  df-pw 4604  df-sn 4629  df-pr 4631  df-op 4635  df-uni 4909  df-int 4951  df-br 5149  df-opab 5211  df-mpt 5232  df-tr 5266  df-id 5574  df-eprel 5580  df-po 5588  df-so 5589  df-fr 5631  df-we 5633  df-xp 5682  df-rel 5683  df-cnv 5684  df-co 5685  df-dm 5686  df-rn 5687  df-res 5688  df-ima 5689  df-ord 6367  df-on 6368  df-iota 6495  df-fun 6545  df-fn 6546  df-f 6547  df-f1 6548  df-fo 6549  df-f1o 6550  df-fv 6551  df-en 8939  df-card 9933  df-cf 9935
This theorem is referenced by:  cfom  10258  cfidm  10269  alephreg  10576  winafp  10691  tskcard  10775  gruina  10812
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