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Theorem fidomdm 7154
Description: Any finite set dominates its domain. (Contributed by Mario Carneiro, 22-Sep-2013.) (Revised by Mario Carneiro, 16-Nov-2014.)
Assertion
Ref Expression
fidomdm  |-  ( F  e.  Fin  ->  dom  F  ~<_  F )

Proof of Theorem fidomdm
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 dmresv 5148 . 2  |-  dom  ( F  |`  _V )  =  dom  F
2 resss 4995 . . . . 5  |-  ( F  |`  _V )  C_  F
3 ssfi 7099 . . . . 5  |-  ( ( F  e.  Fin  /\  ( F  |`  _V )  C_  F )  ->  ( F  |`  _V )  e. 
Fin )
42, 3mpan2 652 . . . 4  |-  ( F  e.  Fin  ->  ( F  |`  _V )  e. 
Fin )
5 fvex 5555 . . . . . . 7  |-  ( 1st `  x )  e.  _V
6 eqid 2296 . . . . . . 7  |-  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) )  =  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) )
75, 6fnmpti 5388 . . . . . 6  |-  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) )  Fn  ( F  |`  _V )
8 dffn4 5473 . . . . . 6  |-  ( ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) )  Fn  ( F  |`  _V )  <->  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> ran  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) ) )
97, 8mpbi 199 . . . . 5  |-  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> ran  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) )
10 relres 4999 . . . . . 6  |-  Rel  ( F  |`  _V )
11 reldm 6187 . . . . . 6  |-  ( Rel  ( F  |`  _V )  ->  dom  ( F  |`  _V )  =  ran  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) )
12 foeq3 5465 . . . . . 6  |-  ( dom  ( F  |`  _V )  =  ran  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) )  ->  (
( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) ) : ( F  |`  _V ) -onto-> dom  ( F  |`  _V )  <->  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> ran  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) ) ) )
1310, 11, 12mp2b 9 . . . . 5  |-  ( ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> dom  ( F  |`  _V )  <->  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> ran  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x
) ) )
149, 13mpbir 200 . . . 4  |-  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> dom  ( F  |`  _V )
15 fodomfi 7151 . . . 4  |-  ( ( ( F  |`  _V )  e.  Fin  /\  ( x  e.  ( F  |`  _V )  |->  ( 1st `  x ) ) : ( F  |`  _V ) -onto-> dom  ( F  |`  _V )
)  ->  dom  ( F  |`  _V )  ~<_  ( F  |`  _V ) )
164, 14, 15sylancl 643 . . 3  |-  ( F  e.  Fin  ->  dom  ( F  |`  _V )  ~<_  ( F  |`  _V )
)
17 ssdomg 6923 . . . 4  |-  ( F  e.  Fin  ->  (
( F  |`  _V )  C_  F  ->  ( F  |` 
_V )  ~<_  F ) )
182, 17mpi 16 . . 3  |-  ( F  e.  Fin  ->  ( F  |`  _V )  ~<_  F )
19 domtr 6930 . . 3  |-  ( ( dom  ( F  |`  _V )  ~<_  ( F  |` 
_V )  /\  ( F  |`  _V )  ~<_  F )  ->  dom  ( F  |`  _V )  ~<_  F )
2016, 18, 19syl2anc 642 . 2  |-  ( F  e.  Fin  ->  dom  ( F  |`  _V )  ~<_  F )
211, 20syl5eqbrr 4073 1  |-  ( F  e.  Fin  ->  dom  F  ~<_  F )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 176    = wceq 1632    e. wcel 1696   _Vcvv 2801    C_ wss 3165   class class class wbr 4039    e. cmpt 4093   dom cdm 4705   ran crn 4706    |` cres 4707   Rel wrel 4710    Fn wfn 5266   -onto->wfo 5269   ` cfv 5271   1stc1st 6136    ~<_ cdom 6877   Fincfn 6879
This theorem is referenced by:  dmfi  7155  hashfun  11405
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1536  ax-5 1547  ax-17 1606  ax-9 1644  ax-8 1661  ax-13 1698  ax-14 1700  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277  ax-sep 4157  ax-nul 4165  ax-pow 4204  ax-pr 4230  ax-un 4528
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 1532  df-nf 1535  df-sb 1639  df-eu 2160  df-mo 2161  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-ne 2461  df-ral 2561  df-rex 2562  df-reu 2563  df-rab 2565  df-v 2803  df-sbc 3005  df-dif 3168  df-un 3170  df-in 3172  df-ss 3179  df-pss 3181  df-nul 3469  df-if 3579  df-pw 3640  df-sn 3659  df-pr 3660  df-tp 3661  df-op 3662  df-uni 3844  df-br 4040  df-opab 4094  df-mpt 4095  df-tr 4130  df-eprel 4321  df-id 4325  df-po 4330  df-so 4331  df-fr 4368  df-we 4370  df-ord 4411  df-on 4412  df-lim 4413  df-suc 4414  df-om 4673  df-xp 4711  df-rel 4712  df-cnv 4713  df-co 4714  df-dm 4715  df-rn 4716  df-res 4717  df-ima 4718  df-iota 5235  df-fun 5273  df-fn 5274  df-f 5275  df-f1 5276  df-fo 5277  df-f1o 5278  df-fv 5279  df-1st 6138  df-2nd 6139  df-1o 6495  df-er 6676  df-en 6880  df-dom 6881  df-fin 6883
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