Theorem nftru 1554

Description: The true constant has no free variables. (This can also be proven in one step with nfv 1619, but this proof does not use ax-17 1616.) (Contributed by Mario Carneiro, 6-Oct-2016.)

Assertion

Ref	Expression
nftru	|- F/x T.

Proof of Theorem nftru

Step	Hyp	Ref	Expression
1		tru 1321	. 2 |- T.
2	1	nfth 1553	1 |- F/x T.

Syntax hints:   T. wtru 1316   F/wnf 1544

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546

This theorem depends on definitions:  df-bi 177  df-tru 1319  df-nf 1545

This theorem is referenced by:  sbie  2038  nfeu  2220  nfmo  2221  dvelimc  2511  nfral  2668  nfreu  2786  nfrmo  2787  nfrab  2793  nfsbc  3068  nfcsb  3171  nfiota  4344