Theorem nftru 1490

Description: The true constant has no free variables. (This can also be proven in one step with nfv 1552, but this proof does not use ax-17 1550.) (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 1488	1 |- F/ x T.

Syntax hints:   T. wtru 1374   F/wnf 1484

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 1473

This theorem depends on definitions:  df-bi 117  df-tru 1376  df-nf 1485

This theorem is referenced by:  nfmo  2075  dvelimc  2372  nfralw  2545  nfralxy  2546  nfrexw  2547  nfralya  2548  nfrexya  2549  nfreuw  2683  nfsbc  3026  nfsbcw  3136  nfcsbw  3138  nfcsb  3139  nfiotaw  5255  nfriota  5932  nfixpxy  6827