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Theorem numdom 7665
Description: A set dominated by a numerable set is numerable. (Contributed by Mario Carneiro, 28-Apr-2015.)
Assertion
Ref Expression
numdom  |-  ( ( A  e.  dom  card  /\  B  ~<_  A )  ->  B  e.  dom  card )

Proof of Theorem numdom
StepHypRef Expression
1 cardon 7577 . 2  |-  ( card `  A )  e.  On
2 cardid2 7586 . . . 4  |-  ( A  e.  dom  card  ->  (
card `  A )  ~~  A )
3 domen2 7004 . . . 4  |-  ( (
card `  A )  ~~  A  ->  ( B  ~<_  ( card `  A
)  <->  B  ~<_  A )
)
42, 3syl 15 . . 3  |-  ( A  e.  dom  card  ->  ( B  ~<_  ( card `  A
)  <->  B  ~<_  A )
)
54biimpar 471 . 2  |-  ( ( A  e.  dom  card  /\  B  ~<_  A )  ->  B  ~<_  ( card `  A
) )
6 ondomen 7664 . 2  |-  ( ( ( card `  A
)  e.  On  /\  B  ~<_  ( card `  A
) )  ->  B  e.  dom  card )
71, 5, 6sylancr 644 1  |-  ( ( A  e.  dom  card  /\  B  ~<_  A )  ->  B  e.  dom  card )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 176    /\ wa 358    e. wcel 1684   class class class wbr 4023   Oncon0 4392   dom cdm 4689   ` cfv 5255    ~~ cen 6860    ~<_ cdom 6861   cardccrd 7568
This theorem is referenced by:  ssnum  7666  indcardi  7668  fonum  7685  infpwfien  7689  inffien  7690  unnum  7826  infdif  7835  infxpabs  7838  infunsdom1  7839  infunsdom  7840  infmap2  7844  gchac  8295  grothac  8452  mbfimaopnlem  19010  ttac  27129  isnumbasgrplem2  27269
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1533  ax-5 1544  ax-17 1603  ax-9 1635  ax-8 1643  ax-13 1686  ax-14 1688  ax-6 1703  ax-7 1708  ax-11 1715  ax-12 1866  ax-ext 2264  ax-rep 4131  ax-sep 4141  ax-nul 4149  ax-pow 4188  ax-pr 4214  ax-un 4512
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-tru 1310  df-ex 1529  df-nf 1532  df-sb 1630  df-eu 2147  df-mo 2148  df-clab 2270  df-cleq 2276  df-clel 2279  df-nfc 2408  df-ne 2448  df-ral 2548  df-rex 2549  df-reu 2550  df-rmo 2551  df-rab 2552  df-v 2790  df-sbc 2992  df-csb 3082  df-dif 3155  df-un 3157  df-in 3159  df-ss 3166  df-pss 3168  df-nul 3456  df-if 3566  df-pw 3627  df-sn 3646  df-pr 3647  df-tp 3648  df-op 3649  df-uni 3828  df-int 3863  df-iun 3907  df-br 4024  df-opab 4078  df-mpt 4079  df-tr 4114  df-eprel 4305  df-id 4309  df-po 4314  df-so 4315  df-fr 4352  df-se 4353  df-we 4354  df-ord 4395  df-on 4396  df-suc 4398  df-xp 4695  df-rel 4696  df-cnv 4697  df-co 4698  df-dm 4699  df-rn 4700  df-res 4701  df-ima 4702  df-iota 5219  df-fun 5257  df-fn 5258  df-f 5259  df-f1 5260  df-fo 5261  df-f1o 5262  df-fv 5263  df-isom 5264  df-riota 6304  df-recs 6388  df-er 6660  df-en 6864  df-dom 6865  df-card 7572
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