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Theorem cardonle 7558
Description: The cardinal of an ordinal number is less than or equal to the ordinal number. Proposition 10.6(3) of [TakeutiZaring] p. 85. (Contributed by NM, 22-Oct-2003.)
Assertion
Ref Expression
cardonle  |-  ( A  e.  On  ->  ( card `  A )  C_  A )

Proof of Theorem cardonle
StepHypRef Expression
1 oncardval 7556 . 2  |-  ( A  e.  On  ->  ( card `  A )  = 
|^| { x  e.  On  |  x  ~~  A }
)
2 enrefg 6861 . . 3  |-  ( A  e.  On  ->  A  ~~  A )
3 breq1 4000 . . . 4  |-  ( x  =  A  ->  (
x  ~~  A  <->  A  ~~  A ) )
43intminss 3862 . . 3  |-  ( ( A  e.  On  /\  A  ~~  A )  ->  |^| { x  e.  On  |  x  ~~  A }  C_  A )
52, 4mpdan 652 . 2  |-  ( A  e.  On  ->  |^| { x  e.  On  |  x  ~~  A }  C_  A )
61, 5eqsstrd 3187 1  |-  ( A  e.  On  ->  ( card `  A )  C_  A )
Colors of variables: wff set class
Syntax hints:    -> wi 6    e. wcel 1621   {crab 2522    C_ wss 3127   |^|cint 3836   class class class wbr 3997   Oncon0 4364   ` cfv 4673    ~~ cen 6828   cardccrd 7536
This theorem is referenced by:  card0  7559  iscard  7576  iscard2  7577  carduni  7582  cardom  7587  alephinit  7690  cfle  7848  cfflb  7853  pwfseqlem5  8253
This theorem was proved from axioms:  ax-1 7  ax-2 8  ax-3 9  ax-mp 10  ax-5 1533  ax-6 1534  ax-7 1535  ax-gen 1536  ax-8 1623  ax-11 1624  ax-13 1625  ax-14 1626  ax-17 1628  ax-12o 1664  ax-10 1678  ax-9 1684  ax-4 1692  ax-16 1927  ax-ext 2239  ax-sep 4115  ax-nul 4123  ax-pow 4160  ax-pr 4186  ax-un 4484
This theorem depends on definitions:  df-bi 179  df-or 361  df-an 362  df-3or 940  df-3an 941  df-tru 1315  df-ex 1538  df-nf 1540  df-sb 1884  df-eu 2122  df-mo 2123  df-clab 2245  df-cleq 2251  df-clel 2254  df-nfc 2383  df-ne 2423  df-ral 2523  df-rex 2524  df-rab 2527  df-v 2765  df-sbc 2967  df-dif 3130  df-un 3132  df-in 3134  df-ss 3141  df-pss 3143  df-nul 3431  df-if 3540  df-pw 3601  df-sn 3620  df-pr 3621  df-tp 3622  df-op 3623  df-uni 3802  df-int 3837  df-br 3998  df-opab 4052  df-mpt 4053  df-tr 4088  df-eprel 4277  df-id 4281  df-po 4286  df-so 4287  df-fr 4324  df-we 4326  df-ord 4367  df-on 4368  df-xp 4675  df-rel 4676  df-cnv 4677  df-co 4678  df-dm 4679  df-rn 4680  df-res 4681  df-ima 4682  df-fun 4683  df-fn 4684  df-f 4685  df-f1 4686  df-fo 4687  df-f1o 4688  df-fv 4689  df-en 6832  df-card 7540
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