ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  nfre1 GIF version

Theorem nfre1 2587
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 2528 . 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 2205  wrex 2523
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 2528
This theorem is referenced by:  r19.29an  2687  nfiu1  4026  fun11iun  5640  eusvobj2  6044  fodjuomnilemdc  7448  ismkvnex  7459  prarloclem3step  7827  prmuloc2  7898  ltexprlemm  7931  caucvgprprlemaddq  8039  caucvgsrlemgt1  8126  axpre-suploclemres  8232  supinfneg  9945  infsupneg  9946  lbzbi  9966  divalglemeunn  12632  divalglemeuneg  12634  bezoutlemmain  12719  bezout  12732  lss1d  14657  pw1nct  16903  isomninnlem  16940  trirec0  16954  ismkvnnlem  16963
  Copyright terms: Public domain W3C validator