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Theorem rankung 24798
Description: The rank of the union of two sets. Closed form of rankun 7530. (Contributed by Scott Fenton, 15-Jul-2015.)
Assertion
Ref Expression
rankung  |-  ( ( A  e.  V  /\  B  e.  W )  ->  ( rank `  ( A  u.  B )
)  =  ( (
rank `  A )  u.  ( rank `  B
) ) )

Proof of Theorem rankung
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 uneq1 3324 . . . 4  |-  ( x  =  A  ->  (
x  u.  y )  =  ( A  u.  y ) )
21fveq2d 5531 . . 3  |-  ( x  =  A  ->  ( rank `  ( x  u.  y ) )  =  ( rank `  ( A  u.  y )
) )
3 fveq2 5527 . . . 4  |-  ( x  =  A  ->  ( rank `  x )  =  ( rank `  A
) )
43uneq1d 3330 . . 3  |-  ( x  =  A  ->  (
( rank `  x )  u.  ( rank `  y
) )  =  ( ( rank `  A
)  u.  ( rank `  y ) ) )
52, 4eqeq12d 2299 . 2  |-  ( x  =  A  ->  (
( rank `  ( x  u.  y ) )  =  ( ( rank `  x
)  u.  ( rank `  y ) )  <->  ( rank `  ( A  u.  y
) )  =  ( ( rank `  A
)  u.  ( rank `  y ) ) ) )
6 uneq2 3325 . . . 4  |-  ( y  =  B  ->  ( A  u.  y )  =  ( A  u.  B ) )
76fveq2d 5531 . . 3  |-  ( y  =  B  ->  ( rank `  ( A  u.  y ) )  =  ( rank `  ( A  u.  B )
) )
8 fveq2 5527 . . . 4  |-  ( y  =  B  ->  ( rank `  y )  =  ( rank `  B
) )
98uneq2d 3331 . . 3  |-  ( y  =  B  ->  (
( rank `  A )  u.  ( rank `  y
) )  =  ( ( rank `  A
)  u.  ( rank `  B ) ) )
107, 9eqeq12d 2299 . 2  |-  ( y  =  B  ->  (
( rank `  ( A  u.  y ) )  =  ( ( rank `  A
)  u.  ( rank `  y ) )  <->  ( rank `  ( A  u.  B
) )  =  ( ( rank `  A
)  u.  ( rank `  B ) ) ) )
11 vex 2793 . . 3  |-  x  e. 
_V
12 vex 2793 . . 3  |-  y  e. 
_V
1311, 12rankun 7530 . 2  |-  ( rank `  ( x  u.  y
) )  =  ( ( rank `  x
)  u.  ( rank `  y ) )
145, 10, 13vtocl2g 2849 1  |-  ( ( A  e.  V  /\  B  e.  W )  ->  ( rank `  ( A  u.  B )
)  =  ( (
rank `  A )  u.  ( rank `  B
) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 358    = wceq 1625    e. wcel 1686    u. cun 3152   ` cfv 5257   rankcrnk 7437
This theorem is referenced by:  hfun  24810
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1535  ax-5 1546  ax-17 1605  ax-9 1637  ax-8 1645  ax-13 1688  ax-14 1690  ax-6 1705  ax-7 1710  ax-11 1717  ax-12 1868  ax-ext 2266  ax-rep 4133  ax-sep 4143  ax-nul 4151  ax-pow 4190  ax-pr 4216  ax-un 4514  ax-reg 7308  ax-inf2 7344
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 1531  df-nf 1534  df-sb 1632  df-eu 2149  df-mo 2150  df-clab 2272  df-cleq 2278  df-clel 2281  df-nfc 2410  df-ne 2450  df-ral 2550  df-rex 2551  df-reu 2552  df-rab 2554  df-v 2792  df-sbc 2994  df-csb 3084  df-dif 3157  df-un 3159  df-in 3161  df-ss 3168  df-pss 3170  df-nul 3458  df-if 3568  df-pw 3629  df-sn 3648  df-pr 3649  df-tp 3650  df-op 3651  df-uni 3830  df-int 3865  df-iun 3909  df-br 4026  df-opab 4080  df-mpt 4081  df-tr 4116  df-eprel 4307  df-id 4311  df-po 4316  df-so 4317  df-fr 4354  df-we 4356  df-ord 4397  df-on 4398  df-lim 4399  df-suc 4400  df-om 4659  df-xp 4697  df-rel 4698  df-cnv 4699  df-co 4700  df-dm 4701  df-rn 4702  df-res 4703  df-ima 4704  df-iota 5221  df-fun 5259  df-fn 5260  df-f 5261  df-f1 5262  df-fo 5263  df-f1o 5264  df-fv 5265  df-recs 6390  df-rdg 6425  df-r1 7438  df-rank 7439
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