Theorem nftru 1489

Description: The true constant has no free variables. (This can also be proven in one step with nfv 1551, but this proof does not use ax-17 1549.) (Contributed by Mario Carneiro, 6-Oct-2016.)

Assertion

Ref	Expression
nftru	|- F/ x T.

Proof of Theorem nftru

Step	Hyp	Ref	Expression
1		tru 1377	. 2 |- T.
2	1	nfth 1487	1 |- F/ x T.

Syntax hints:   T. wtru 1374   F/wnf 1483

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-gen 1472

This theorem depends on definitions:  df-bi 117  df-tru 1376  df-nf 1484

This theorem is referenced by:  nfmo  2074  dvelimc  2370  nfralw  2543  nfralxy  2544  nfrexw  2545  nfralya  2546  nfrexya  2547  nfreuxy  2681  nfsbc  3019  nfsbcw  3128  nfcsbw  3130  nfcsb  3131  nfiotaw  5236  nfriota  5909  nfixpxy  6804