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Theorem sbf2 1981
Description: Substitution has no effect on a bound variable. (Contributed by NM, 1-Jul-2005.)
Assertion
Ref Expression
sbf2  |-  ( [ y  /  x ] A. x ph  <->  A. x ph )

Proof of Theorem sbf2
StepHypRef Expression
1 nfa1 1768 . 2  |-  F/ x A. x ph
21sbf 1979 1  |-  ( [ y  /  x ] A. x ph  <->  A. x ph )
Colors of variables: wff set class
Syntax hints:    <-> wb 176   A.wal 1530   [wsb 1638
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
This theorem depends on definitions:  df-bi 177  df-an 360  df-ex 1532  df-nf 1535  df-sb 1639
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