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Theorem ralidm 3723
Description: Idempotent law for restricted quantifier. (Contributed by NM, 28-Mar-1997.)
Assertion
Ref Expression
ralidm  |-  ( A. x  e.  A  A. x  e.  A  ph  <->  A. x  e.  A  ph )
Distinct variable group:    x, A
Allowed substitution hint:    ph( x)

Proof of Theorem ralidm
StepHypRef Expression
1 rzal 3721 . . 3  |-  ( A  =  (/)  ->  A. x  e.  A  A. x  e.  A  ph )
2 rzal 3721 . . 3  |-  ( A  =  (/)  ->  A. x  e.  A  ph )
31, 22thd 232 . 2  |-  ( A  =  (/)  ->  ( A. x  e.  A  A. x  e.  A  ph  <->  A. x  e.  A  ph ) )
4 neq0 3630 . . 3  |-  ( -.  A  =  (/)  <->  E. x  x  e.  A )
5 biimt 326 . . . 4  |-  ( E. x  x  e.  A  ->  ( A. x  e.  A  ph  <->  ( E. x  x  e.  A  ->  A. x  e.  A  ph ) ) )
6 df-ral 2702 . . . . 5  |-  ( A. x  e.  A  A. x  e.  A  ph  <->  A. x
( x  e.  A  ->  A. x  e.  A  ph ) )
7 nfra1 2748 . . . . . 6  |-  F/ x A. x  e.  A  ph
8719.23 1819 . . . . 5  |-  ( A. x ( x  e.  A  ->  A. x  e.  A  ph )  <->  ( E. x  x  e.  A  ->  A. x  e.  A  ph ) )
96, 8bitri 241 . . . 4  |-  ( A. x  e.  A  A. x  e.  A  ph  <->  ( E. x  x  e.  A  ->  A. x  e.  A  ph ) )
105, 9syl6rbbr 256 . . 3  |-  ( E. x  x  e.  A  ->  ( A. x  e.  A  A. x  e.  A  ph  <->  A. x  e.  A  ph ) )
114, 10sylbi 188 . 2  |-  ( -.  A  =  (/)  ->  ( A. x  e.  A  A. x  e.  A  ph  <->  A. x  e.  A  ph ) )
123, 11pm2.61i 158 1  |-  ( A. x  e.  A  A. x  e.  A  ph  <->  A. x  e.  A  ph )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    <-> wb 177   A.wal 1549   E.wex 1550    = wceq 1652    e. wcel 1725   A.wral 2697   (/)c0 3620
This theorem is referenced by:  dfwe2  4754  issref  5239  cnvpo  5402
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1555  ax-5 1566  ax-17 1626  ax-9 1666  ax-8 1687  ax-6 1744  ax-7 1749  ax-11 1761  ax-12 1950  ax-ext 2416
This theorem depends on definitions:  df-bi 178  df-or 360  df-an 361  df-tru 1328  df-ex 1551  df-nf 1554  df-sb 1659  df-clab 2422  df-cleq 2428  df-clel 2431  df-nfc 2560  df-ne 2600  df-ral 2702  df-v 2950  df-dif 3315  df-nul 3621
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