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Theorem cardlim 9913
Description: An infinite cardinal is a limit ordinal. Equivalent to Exercise 4 of [TakeutiZaring] p. 91. (Contributed by Mario Carneiro, 13-Jan-2013.)
Assertion
Ref Expression
cardlim (Ο‰ βŠ† (cardβ€˜π΄) ↔ Lim (cardβ€˜π΄))

Proof of Theorem cardlim
Dummy variable π‘₯ is distinct from all other variables.
StepHypRef Expression
1 sseq2 3971 . . . . . . . . . . 11 ((cardβ€˜π΄) = suc π‘₯ β†’ (Ο‰ βŠ† (cardβ€˜π΄) ↔ Ο‰ βŠ† suc π‘₯))
21biimpd 228 . . . . . . . . . 10 ((cardβ€˜π΄) = suc π‘₯ β†’ (Ο‰ βŠ† (cardβ€˜π΄) β†’ Ο‰ βŠ† suc π‘₯))
3 limom 7819 . . . . . . . . . . . 12 Lim Ο‰
4 limsssuc 7787 . . . . . . . . . . . 12 (Lim Ο‰ β†’ (Ο‰ βŠ† π‘₯ ↔ Ο‰ βŠ† suc π‘₯))
53, 4ax-mp 5 . . . . . . . . . . 11 (Ο‰ βŠ† π‘₯ ↔ Ο‰ βŠ† suc π‘₯)
6 infensuc 9102 . . . . . . . . . . . 12 ((π‘₯ ∈ On ∧ Ο‰ βŠ† π‘₯) β†’ π‘₯ β‰ˆ suc π‘₯)
76ex 414 . . . . . . . . . . 11 (π‘₯ ∈ On β†’ (Ο‰ βŠ† π‘₯ β†’ π‘₯ β‰ˆ suc π‘₯))
85, 7biimtrrid 242 . . . . . . . . . 10 (π‘₯ ∈ On β†’ (Ο‰ βŠ† suc π‘₯ β†’ π‘₯ β‰ˆ suc π‘₯))
92, 8sylan9r 510 . . . . . . . . 9 ((π‘₯ ∈ On ∧ (cardβ€˜π΄) = suc π‘₯) β†’ (Ο‰ βŠ† (cardβ€˜π΄) β†’ π‘₯ β‰ˆ suc π‘₯))
10 breq2 5110 . . . . . . . . . 10 ((cardβ€˜π΄) = suc π‘₯ β†’ (π‘₯ β‰ˆ (cardβ€˜π΄) ↔ π‘₯ β‰ˆ suc π‘₯))
1110adantl 483 . . . . . . . . 9 ((π‘₯ ∈ On ∧ (cardβ€˜π΄) = suc π‘₯) β†’ (π‘₯ β‰ˆ (cardβ€˜π΄) ↔ π‘₯ β‰ˆ suc π‘₯))
129, 11sylibrd 259 . . . . . . . 8 ((π‘₯ ∈ On ∧ (cardβ€˜π΄) = suc π‘₯) β†’ (Ο‰ βŠ† (cardβ€˜π΄) β†’ π‘₯ β‰ˆ (cardβ€˜π΄)))
1312ex 414 . . . . . . 7 (π‘₯ ∈ On β†’ ((cardβ€˜π΄) = suc π‘₯ β†’ (Ο‰ βŠ† (cardβ€˜π΄) β†’ π‘₯ β‰ˆ (cardβ€˜π΄))))
1413com3r 87 . . . . . 6 (Ο‰ βŠ† (cardβ€˜π΄) β†’ (π‘₯ ∈ On β†’ ((cardβ€˜π΄) = suc π‘₯ β†’ π‘₯ β‰ˆ (cardβ€˜π΄))))
1514imp 408 . . . . 5 ((Ο‰ βŠ† (cardβ€˜π΄) ∧ π‘₯ ∈ On) β†’ ((cardβ€˜π΄) = suc π‘₯ β†’ π‘₯ β‰ˆ (cardβ€˜π΄)))
16 vex 3448 . . . . . . . . . 10 π‘₯ ∈ V
1716sucid 6400 . . . . . . . . 9 π‘₯ ∈ suc π‘₯
18 eleq2 2823 . . . . . . . . 9 ((cardβ€˜π΄) = suc π‘₯ β†’ (π‘₯ ∈ (cardβ€˜π΄) ↔ π‘₯ ∈ suc π‘₯))
1917, 18mpbiri 258 . . . . . . . 8 ((cardβ€˜π΄) = suc π‘₯ β†’ π‘₯ ∈ (cardβ€˜π΄))
20 cardidm 9900 . . . . . . . 8 (cardβ€˜(cardβ€˜π΄)) = (cardβ€˜π΄)
2119, 20eleqtrrdi 2845 . . . . . . 7 ((cardβ€˜π΄) = suc π‘₯ β†’ π‘₯ ∈ (cardβ€˜(cardβ€˜π΄)))
22 cardne 9906 . . . . . . 7 (π‘₯ ∈ (cardβ€˜(cardβ€˜π΄)) β†’ Β¬ π‘₯ β‰ˆ (cardβ€˜π΄))
2321, 22syl 17 . . . . . 6 ((cardβ€˜π΄) = suc π‘₯ β†’ Β¬ π‘₯ β‰ˆ (cardβ€˜π΄))
2423a1i 11 . . . . 5 ((Ο‰ βŠ† (cardβ€˜π΄) ∧ π‘₯ ∈ On) β†’ ((cardβ€˜π΄) = suc π‘₯ β†’ Β¬ π‘₯ β‰ˆ (cardβ€˜π΄)))
2515, 24pm2.65d 195 . . . 4 ((Ο‰ βŠ† (cardβ€˜π΄) ∧ π‘₯ ∈ On) β†’ Β¬ (cardβ€˜π΄) = suc π‘₯)
2625nrexdv 3143 . . 3 (Ο‰ βŠ† (cardβ€˜π΄) β†’ Β¬ βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯)
27 peano1 7826 . . . . . 6 βˆ… ∈ Ο‰
28 ssel 3938 . . . . . 6 (Ο‰ βŠ† (cardβ€˜π΄) β†’ (βˆ… ∈ Ο‰ β†’ βˆ… ∈ (cardβ€˜π΄)))
2927, 28mpi 20 . . . . 5 (Ο‰ βŠ† (cardβ€˜π΄) β†’ βˆ… ∈ (cardβ€˜π΄))
30 n0i 4294 . . . . 5 (βˆ… ∈ (cardβ€˜π΄) β†’ Β¬ (cardβ€˜π΄) = βˆ…)
31 cardon 9885 . . . . . . . . 9 (cardβ€˜π΄) ∈ On
3231onordi 6429 . . . . . . . 8 Ord (cardβ€˜π΄)
33 ordzsl 7782 . . . . . . . 8 (Ord (cardβ€˜π΄) ↔ ((cardβ€˜π΄) = βˆ… ∨ βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄)))
3432, 33mpbi 229 . . . . . . 7 ((cardβ€˜π΄) = βˆ… ∨ βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄))
35 3orass 1091 . . . . . . 7 (((cardβ€˜π΄) = βˆ… ∨ βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄)) ↔ ((cardβ€˜π΄) = βˆ… ∨ (βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄))))
3634, 35mpbi 229 . . . . . 6 ((cardβ€˜π΄) = βˆ… ∨ (βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄)))
3736ori 860 . . . . 5 (Β¬ (cardβ€˜π΄) = βˆ… β†’ (βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄)))
3829, 30, 373syl 18 . . . 4 (Ο‰ βŠ† (cardβ€˜π΄) β†’ (βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ ∨ Lim (cardβ€˜π΄)))
3938ord 863 . . 3 (Ο‰ βŠ† (cardβ€˜π΄) β†’ (Β¬ βˆƒπ‘₯ ∈ On (cardβ€˜π΄) = suc π‘₯ β†’ Lim (cardβ€˜π΄)))
4026, 39mpd 15 . 2 (Ο‰ βŠ† (cardβ€˜π΄) β†’ Lim (cardβ€˜π΄))
41 limomss 7808 . 2 (Lim (cardβ€˜π΄) β†’ Ο‰ βŠ† (cardβ€˜π΄))
4240, 41impbii 208 1 (Ο‰ βŠ† (cardβ€˜π΄) ↔ Lim (cardβ€˜π΄))
Colors of variables: wff setvar class
Syntax hints:  Β¬ wn 3   β†’ wi 4   ↔ wb 205   ∧ wa 397   ∨ wo 846   ∨ w3o 1087   = wceq 1542   ∈ wcel 2107  βˆƒwrex 3070   βŠ† wss 3911  βˆ…c0 4283   class class class wbr 5106  Ord word 6317  Oncon0 6318  Lim wlim 6319  suc csuc 6320  β€˜cfv 6497  Ο‰com 7803   β‰ˆ cen 8883  cardccrd 9876
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2155  ax-12 2172  ax-ext 2704  ax-sep 5257  ax-nul 5264  ax-pow 5321  ax-pr 5385  ax-un 7673
This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3or 1089  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-nf 1787  df-sb 2069  df-mo 2535  df-eu 2564  df-clab 2711  df-cleq 2725  df-clel 2811  df-nfc 2886  df-ne 2941  df-ral 3062  df-rex 3071  df-rab 3407  df-v 3446  df-sbc 3741  df-csb 3857  df-dif 3914  df-un 3916  df-in 3918  df-ss 3928  df-pss 3930  df-nul 4284  df-if 4488  df-pw 4563  df-sn 4588  df-pr 4590  df-op 4594  df-uni 4867  df-int 4909  df-br 5107  df-opab 5169  df-mpt 5190  df-tr 5224  df-id 5532  df-eprel 5538  df-po 5546  df-so 5547  df-fr 5589  df-we 5591  df-xp 5640  df-rel 5641  df-cnv 5642  df-co 5643  df-dm 5644  df-rn 5645  df-res 5646  df-ima 5647  df-ord 6321  df-on 6322  df-lim 6323  df-suc 6324  df-iota 6449  df-fun 6499  df-fn 6500  df-f 6501  df-f1 6502  df-fo 6503  df-f1o 6504  df-fv 6505  df-om 7804  df-er 8651  df-en 8887  df-dom 8888  df-card 9880
This theorem is referenced by:  infxpenlem  9954  alephislim  10024  cflim2  10204  winalim  10636  gruina  10759
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