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Theorem xp2cda 8016
Description: Two times a cardinal number. Exercise 4.56(g) of [Mendelson] p. 258. (Contributed by NM, 27-Sep-2004.) (Revised by Mario Carneiro, 29-Apr-2015.)
Assertion
Ref Expression
xp2cda  |-  ( A  e.  V  ->  ( A  X.  2o )  =  ( A  +c  A
) )

Proof of Theorem xp2cda
StepHypRef Expression
1 cdaval 8006 . . 3  |-  ( ( A  e.  V  /\  A  e.  V )  ->  ( A  +c  A
)  =  ( ( A  X.  { (/) } )  u.  ( A  X.  { 1o }
) ) )
21anidms 627 . 2  |-  ( A  e.  V  ->  ( A  +c  A )  =  ( ( A  X.  { (/) } )  u.  ( A  X.  { 1o } ) ) )
3 df2o3 6696 . . . . 5  |-  2o  =  { (/) ,  1o }
4 df-pr 3781 . . . . 5  |-  { (/) ,  1o }  =  ( { (/) }  u.  { 1o } )
53, 4eqtri 2424 . . . 4  |-  2o  =  ( { (/) }  u.  { 1o } )
65xpeq2i 4858 . . 3  |-  ( A  X.  2o )  =  ( A  X.  ( { (/) }  u.  { 1o } ) )
7 xpundi 4889 . . 3  |-  ( A  X.  ( { (/) }  u.  { 1o }
) )  =  ( ( A  X.  { (/)
} )  u.  ( A  X.  { 1o }
) )
86, 7eqtri 2424 . 2  |-  ( A  X.  2o )  =  ( ( A  X.  { (/) } )  u.  ( A  X.  { 1o } ) )
92, 8syl6reqr 2455 1  |-  ( A  e.  V  ->  ( A  X.  2o )  =  ( A  +c  A
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1649    e. wcel 1721    u. cun 3278   (/)c0 3588   {csn 3774   {cpr 3775    X. cxp 4835  (class class class)co 6040   1oc1o 6676   2oc2o 6677    +c ccda 8003
This theorem is referenced by:  pwcda1  8030  unctb  8041  infcdaabs  8042  ackbij1lem5  8060  fin56  8229
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1552  ax-5 1563  ax-17 1623  ax-9 1662  ax-8 1683  ax-13 1723  ax-14 1725  ax-6 1740  ax-7 1745  ax-11 1757  ax-12 1946  ax-ext 2385  ax-sep 4290  ax-nul 4298  ax-pow 4337  ax-pr 4363  ax-un 4660
This theorem depends on definitions:  df-bi 178  df-or 360  df-an 361  df-3an 938  df-tru 1325  df-ex 1548  df-nf 1551  df-sb 1656  df-eu 2258  df-mo 2259  df-clab 2391  df-cleq 2397  df-clel 2400  df-nfc 2529  df-ne 2569  df-ral 2671  df-rex 2672  df-rab 2675  df-v 2918  df-sbc 3122  df-dif 3283  df-un 3285  df-in 3287  df-ss 3294  df-nul 3589  df-if 3700  df-pw 3761  df-sn 3780  df-pr 3781  df-op 3783  df-uni 3976  df-br 4173  df-opab 4227  df-id 4458  df-suc 4547  df-xp 4843  df-rel 4844  df-cnv 4845  df-co 4846  df-dm 4847  df-iota 5377  df-fun 5415  df-fv 5421  df-ov 6043  df-oprab 6044  df-mpt2 6045  df-1o 6683  df-2o 6684  df-cda 8004
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