Theorem nfnin 3228

Description: Hypothesis builder for anti-intersection. (Contributed by SF, 2-Jan-2018.)

Hypotheses

Ref	Expression
nfnin.1	|- F/_xA
nfnin.2	|- F/_xB

Assertion

Ref	Expression
nfnin	|- F/_x(A &ncap B)

Proof of Theorem nfnin

Dummy variable y is distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-nin 3211	. 2 |- (A &ncap B) = {y | (y e. A -/\ y e. B)}
2		nfnin.1	. . . . 5 |- F/_xA
3	2	nfel2 2501	. . . 4 |- F/x y e. A
4		nfnin.2	. . . . 5 |- F/_xB
5	4	nfel2 2501	. . . 4 |- F/x y e. B
6	3, 5	nfnan 1825	. . 3 |- F/x(y e. A -/\ y e. B)
7	6	nfab 2493	. 2 |- F/_x{y | (y e. A -/\ y e. B)}
8	1, 7	nfcxfr 2486	1 |- F/_x(A &ncap B)

Syntax hints:   -/\ wnan 1287   e. wcel 1710  {cab 2339   F/_wnfc 2476   &ncap cnin 3204

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-nin 3211

This theorem is referenced by:  nfcompl  3229  nfin  3230  nfun  3231