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Theorem rankung 26138
Description: The rank of the union of two sets. Closed form of rankun 7811. (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 3480 . . . 4  |-  ( x  =  A  ->  (
x  u.  y )  =  ( A  u.  y ) )
21fveq2d 5761 . . 3  |-  ( x  =  A  ->  ( rank `  ( x  u.  y ) )  =  ( rank `  ( A  u.  y )
) )
3 fveq2 5757 . . . 4  |-  ( x  =  A  ->  ( rank `  x )  =  ( rank `  A
) )
43uneq1d 3486 . . 3  |-  ( x  =  A  ->  (
( rank `  x )  u.  ( rank `  y
) )  =  ( ( rank `  A
)  u.  ( rank `  y ) ) )
52, 4eqeq12d 2456 . 2  |-  ( x  =  A  ->  (
( rank `  ( x  u.  y ) )  =  ( ( rank `  x
)  u.  ( rank `  y ) )  <->  ( rank `  ( A  u.  y
) )  =  ( ( rank `  A
)  u.  ( rank `  y ) ) ) )
6 uneq2 3481 . . . 4  |-  ( y  =  B  ->  ( A  u.  y )  =  ( A  u.  B ) )
76fveq2d 5761 . . 3  |-  ( y  =  B  ->  ( rank `  ( A  u.  y ) )  =  ( rank `  ( A  u.  B )
) )
8 fveq2 5757 . . . 4  |-  ( y  =  B  ->  ( rank `  y )  =  ( rank `  B
) )
98uneq2d 3487 . . 3  |-  ( y  =  B  ->  (
( rank `  A )  u.  ( rank `  y
) )  =  ( ( rank `  A
)  u.  ( rank `  B ) ) )
107, 9eqeq12d 2456 . 2  |-  ( y  =  B  ->  (
( rank `  ( A  u.  y ) )  =  ( ( rank `  A
)  u.  ( rank `  y ) )  <->  ( rank `  ( A  u.  B
) )  =  ( ( rank `  A
)  u.  ( rank `  B ) ) ) )
11 vex 2965 . . 3  |-  x  e. 
_V
12 vex 2965 . . 3  |-  y  e. 
_V
1311, 12rankun 7811 . 2  |-  ( rank `  ( x  u.  y
) )  =  ( ( rank `  x
)  u.  ( rank `  y ) )
145, 10, 13vtocl2g 3021 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 360    = wceq 1653    e. wcel 1727    u. cun 3304   ` cfv 5483   rankcrnk 7718
This theorem is referenced by:  hfun  26150
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1556  ax-5 1567  ax-17 1627  ax-9 1668  ax-8 1689  ax-13 1729  ax-14 1731  ax-6 1746  ax-7 1751  ax-11 1763  ax-12 1953  ax-ext 2423  ax-rep 4345  ax-sep 4355  ax-nul 4363  ax-pow 4406  ax-pr 4432  ax-un 4730  ax-reg 7589  ax-inf2 7625
This theorem depends on definitions:  df-bi 179  df-or 361  df-an 362  df-3or 938  df-3an 939  df-tru 1329  df-ex 1552  df-nf 1555  df-sb 1660  df-eu 2291  df-mo 2292  df-clab 2429  df-cleq 2435  df-clel 2438  df-nfc 2567  df-ne 2607  df-ral 2716  df-rex 2717  df-reu 2718  df-rab 2720  df-v 2964  df-sbc 3168  df-csb 3268  df-dif 3309  df-un 3311  df-in 3313  df-ss 3320  df-pss 3322  df-nul 3614  df-if 3764  df-pw 3825  df-sn 3844  df-pr 3845  df-tp 3846  df-op 3847  df-uni 4040  df-int 4075  df-iun 4119  df-br 4238  df-opab 4292  df-mpt 4293  df-tr 4328  df-eprel 4523  df-id 4527  df-po 4532  df-so 4533  df-fr 4570  df-we 4572  df-ord 4613  df-on 4614  df-lim 4615  df-suc 4616  df-om 4875  df-xp 4913  df-rel 4914  df-cnv 4915  df-co 4916  df-dm 4917  df-rn 4918  df-res 4919  df-ima 4920  df-iota 5447  df-fun 5485  df-fn 5486  df-f 5487  df-f1 5488  df-fo 5489  df-f1o 5490  df-fv 5491  df-recs 6662  df-rdg 6697  df-r1 7719  df-rank 7720
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