Theorem nfrecs

Description: Bound-variable hypothesis builder for recs . (Contributed by Stefan O'Rear, 18-Jan-2015)

	Ref	Expression
Hypothesis	nfrecs.f	|- F/_ x F
Assertion	nfrecs	|- F/_ x recs ( F )

Proof

Step	Hyp	Ref	Expression
1		nfrecs.f	|- F/_ x F
2		df-recs	|- recs ( F ) = wrecs ( _E , On , F )
3		nfcv	|- F/_ x _E
4		nfcv	|- F/_ x On
5	3 4 1	nfwrecs	|- F/_ x wrecs ( _E , On , F )
6	2 5	nfcxfr	|- F/_ x recs ( F )