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Theorem cardprc 8996
Description: The class of all cardinal numbers is not a set (i.e. is a proper class). Theorem 19.8 of [Eisenberg] p. 310. In this proof (which does not use AC), we cannot use Cantor's construction canth3 9575 to ensure that there is always a cardinal larger than a given cardinal, but we can use Hartogs' construction hartogs 8614 to construct (effectively) (ℵ‘suc 𝐴) from (ℵ‘𝐴), which achieves the same thing. (Contributed by Mario Carneiro, 22-Jan-2013.)
Assertion
Ref Expression
cardprc {𝑥 ∣ (card‘𝑥) = 𝑥} ∉ V

Proof of Theorem cardprc
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 fveq2 6352 . . . . 5 (𝑥 = 𝑦 → (card‘𝑥) = (card‘𝑦))
2 id 22 . . . . 5 (𝑥 = 𝑦𝑥 = 𝑦)
31, 2eqeq12d 2775 . . . 4 (𝑥 = 𝑦 → ((card‘𝑥) = 𝑥 ↔ (card‘𝑦) = 𝑦))
43cbvabv 2885 . . 3 {𝑥 ∣ (card‘𝑥) = 𝑥} = {𝑦 ∣ (card‘𝑦) = 𝑦}
54cardprclem 8995 . 2 ¬ {𝑥 ∣ (card‘𝑥) = 𝑥} ∈ V
65nelir 3038 1 {𝑥 ∣ (card‘𝑥) = 𝑥} ∉ V
Colors of variables: wff setvar class
Syntax hints:   = wceq 1632  {cab 2746  wnel 3035  Vcvv 3340  cfv 6049  cardccrd 8951
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1871  ax-4 1886  ax-5 1988  ax-6 2054  ax-7 2090  ax-8 2141  ax-9 2148  ax-10 2168  ax-11 2183  ax-12 2196  ax-13 2391  ax-ext 2740  ax-rep 4923  ax-sep 4933  ax-nul 4941  ax-pow 4992  ax-pr 5055  ax-un 7114
This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-3or 1073  df-3an 1074  df-tru 1635  df-ex 1854  df-nf 1859  df-sb 2047  df-eu 2611  df-mo 2612  df-clab 2747  df-cleq 2753  df-clel 2756  df-nfc 2891  df-ne 2933  df-nel 3036  df-ral 3055  df-rex 3056  df-reu 3057  df-rmo 3058  df-rab 3059  df-v 3342  df-sbc 3577  df-csb 3675  df-dif 3718  df-un 3720  df-in 3722  df-ss 3729  df-pss 3731  df-nul 4059  df-if 4231  df-pw 4304  df-sn 4322  df-pr 4324  df-tp 4326  df-op 4328  df-uni 4589  df-int 4628  df-iun 4674  df-br 4805  df-opab 4865  df-mpt 4882  df-tr 4905  df-id 5174  df-eprel 5179  df-po 5187  df-so 5188  df-fr 5225  df-se 5226  df-we 5227  df-xp 5272  df-rel 5273  df-cnv 5274  df-co 5275  df-dm 5276  df-rn 5277  df-res 5278  df-ima 5279  df-pred 5841  df-ord 5887  df-on 5888  df-lim 5889  df-suc 5890  df-iota 6012  df-fun 6051  df-fn 6052  df-f 6053  df-f1 6054  df-fo 6055  df-f1o 6056  df-fv 6057  df-isom 6058  df-riota 6774  df-wrecs 7576  df-recs 7637  df-er 7911  df-en 8122  df-dom 8123  df-sdom 8124  df-oi 8580  df-har 8628  df-card 8955
This theorem is referenced by:  alephprc  9112
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