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Theorem dfdmf 4889
Description: Definition of domain, using bound-variable hypotheses instead of distinct variable conditions. (Contributed by NM, 8-Mar-1995.) (Revised by Mario Carneiro, 15-Oct-2016.)
Hypotheses
Ref Expression
dfdmf.1  |-  F/_ x A
dfdmf.2  |-  F/_ y A
Assertion
Ref Expression
dfdmf  |-  dom  A  =  { x  |  E. y  x A y }
Distinct variable group:    x, y
Allowed substitution hints:    A( x, y)

Proof of Theorem dfdmf
Dummy variables  w  v are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 df-dm 4715 . 2  |-  dom  A  =  { w  |  E. v  w A v }
2 nfcv 2432 . . . . 5  |-  F/_ y
w
3 dfdmf.2 . . . . 5  |-  F/_ y A
4 nfcv 2432 . . . . 5  |-  F/_ y
v
52, 3, 4nfbr 4083 . . . 4  |-  F/ y  w A v
6 nfv 1609 . . . 4  |-  F/ v  w A y
7 breq2 4043 . . . 4  |-  ( v  =  y  ->  (
w A v  <->  w A
y ) )
85, 6, 7cbvex 1938 . . 3  |-  ( E. v  w A v  <->  E. y  w A
y )
98abbii 2408 . 2  |-  { w  |  E. v  w A v }  =  {
w  |  E. y  w A y }
10 nfcv 2432 . . . . 5  |-  F/_ x w
11 dfdmf.1 . . . . 5  |-  F/_ x A
12 nfcv 2432 . . . . 5  |-  F/_ x
y
1310, 11, 12nfbr 4083 . . . 4  |-  F/ x  w A y
1413nfex 1779 . . 3  |-  F/ x E. y  w A
y
15 nfv 1609 . . 3  |-  F/ w E. y  x A
y
16 breq1 4042 . . . 4  |-  ( w  =  x  ->  (
w A y  <->  x A
y ) )
1716exbidv 1616 . . 3  |-  ( w  =  x  ->  ( E. y  w A
y  <->  E. y  x A y ) )
1814, 15, 17cbvab 2414 . 2  |-  { w  |  E. y  w A y }  =  {
x  |  E. y  x A y }
191, 9, 183eqtri 2320 1  |-  dom  A  =  { x  |  E. y  x A y }
Colors of variables: wff set class
Syntax hints:   E.wex 1531    = wceq 1632   {cab 2282   F/_wnfc 2419   class class class wbr 4039   dom cdm 4705
This theorem is referenced by:  dmopab  4905
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-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-rab 2565  df-v 2803  df-dif 3168  df-un 3170  df-in 3172  df-ss 3179  df-nul 3469  df-if 3579  df-sn 3659  df-pr 3660  df-op 3662  df-br 4040  df-dm 4715
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