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Theorem nfre1 2518
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 2459 . 2 (∃𝑥𝐴 𝜑 ↔ ∃𝑥(𝑥𝐴𝜑))
2 nfe1 1494 . 2 𝑥𝑥(𝑥𝐴𝜑)
31, 2nfxfr 1472 1 𝑥𝑥𝐴 𝜑
Colors of variables: wff set class
Syntax hints:  wa 104  wnf 1458  wex 1490  wcel 2146  wrex 2454
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 1445  ax-gen 1447  ax-ie1 1491
This theorem depends on definitions:  df-bi 117  df-nf 1459  df-rex 2459
This theorem is referenced by:  r19.29an  2617  nfiu1  3912  fun11iun  5474  eusvobj2  5851  fodjuomnilemdc  7132  ismkvnex  7143  prarloclem3step  7470  prmuloc2  7541  ltexprlemm  7574  caucvgprprlemaddq  7682  caucvgsrlemgt1  7769  axpre-suploclemres  7875  supinfneg  9566  infsupneg  9567  lbzbi  9587  divalglemeunn  11891  divalglemeuneg  11893  bezoutlemmain  11964  bezout  11977  pw1nct  14293  isomninnlem  14319  trirec0  14333  ismkvnnlem  14341
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