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Theorem nfre1 2575
Description: 𝑥 is not free in 𝑥𝐴𝜑. (Contributed by NM, 19-Mar-1997.) (Revised by Mario Carneiro, 7-Oct-2016.)
Assertion
Ref Expression
nfre1 𝑥𝑥𝐴 𝜑

Proof of Theorem nfre1
StepHypRef Expression
1 df-rex 2516 . 2 (∃𝑥𝐴 𝜑 ↔ ∃𝑥(𝑥𝐴𝜑))
2 nfe1 1544 . 2 𝑥𝑥(𝑥𝐴𝜑)
31, 2nfxfr 1522 1 𝑥𝑥𝐴 𝜑
Colors of variables: wff set class
Syntax hints:  wa 104  wnf 1508  wex 1540  wcel 2202  wrex 2511
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1495  ax-gen 1497  ax-ie1 1541
This theorem depends on definitions:  df-bi 117  df-nf 1509  df-rex 2516
This theorem is referenced by:  r19.29an  2675  nfiu1  4000  fun11iun  5604  eusvobj2  6003  fodjuomnilemdc  7342  ismkvnex  7353  prarloclem3step  7715  prmuloc2  7786  ltexprlemm  7819  caucvgprprlemaddq  7927  caucvgsrlemgt1  8014  axpre-suploclemres  8120  supinfneg  9828  infsupneg  9829  lbzbi  9849  divalglemeunn  12481  divalglemeuneg  12483  bezoutlemmain  12568  bezout  12581  lss1d  14396  pw1nct  16604  isomninnlem  16634  trirec0  16648  ismkvnnlem  16656
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