Theorem nfr 1873

Description: Consequence of the definition of not-free. (Contributed by Mario Carneiro, 26-Sep-2016.)

Assertion

Ref	Expression
nfr

Proof of Theorem nfr

Step	Hyp	Ref	Expression
1		df-nf 1617	. 2
2		sp 1859	. 2
3	1, 2	sylbi 195	1

Syntax hints:  ->wi 4  A.wal 1393  F/wnf 1616

This theorem is referenced by:  nfri  1874  nfrd  1875  19.21t  1904  19.23t  1909  nfimd  1917  sbft  2120  wl-nfeqfb  29990  bj-alrim  34246  bj-nexdt  34250  bj-cbv3tb  34271  bj-nfs1t2  34275  bj-sbftv  34345  bj-equsal1t  34395  stdpc5t  34400

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1618  ax-4 1631  ax-5 1704  ax-6 1747  ax-7 1790  ax-12 1854

This theorem depends on definitions:  df-bi 185  df-ex 1613  df-nf 1617