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Theorem nfre1 2585
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 2526 . 2 (∃𝑥𝐴 𝜑 ↔ ∃𝑥(𝑥𝐴𝜑))
2 nfe1 1545 . 2 𝑥𝑥(𝑥𝐴𝜑)
31, 2nfxfr 1523 1 𝑥𝑥𝐴 𝜑
Colors of variables: wff set class
Syntax hints:  wa 104  wnf 1509  wex 1541  wcel 2203  wrex 2521
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 1496  ax-gen 1498  ax-ie1 1542
This theorem depends on definitions:  df-bi 117  df-nf 1510  df-rex 2526
This theorem is referenced by:  r19.29an  2685  nfiu1  4021  fun11iun  5635  eusvobj2  6036  fodjuomnilemdc  7435  ismkvnex  7446  prarloclem3step  7811  prmuloc2  7882  ltexprlemm  7915  caucvgprprlemaddq  8023  caucvgsrlemgt1  8110  axpre-suploclemres  8216  supinfneg  9927  infsupneg  9928  lbzbi  9948  divalglemeunn  12607  divalglemeuneg  12609  bezoutlemmain  12694  bezout  12707  lss1d  14531  pw1nct  16777  isomninnlem  16814  trirec0  16828  ismkvnnlem  16837
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