Theorem nfixp1 6718

Description: The index variable in an indexed Cartesian product is not free. (Contributed by Jeff Madsen, 19-Jun-2011.) (Revised by Mario Carneiro, 15-Oct-2016.)

Assertion

Ref	Expression
nfixp1	|- F/_ x X_ x e. A B

Proof of Theorem nfixp1

Dummy variable y is distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-ixp 6699	. 2 |- X_ x e. A B = { y | ( y Fn { x | x e. A } /\ A. x e. A ( y ` x ) e. B ) }
2		nfcv 2319	. . . . 5 |- F/_ x y
3		nfab1 2321	. . . . 5 |- F/_ x { x | x e. A }
4	2, 3	nffn 5313	. . . 4 |- F/ x y Fn { x | x e. A }
5		nfra1 2508	. . . 4 |- F/ x A. x e. A ( y ` x ) e. B
6	4, 5	nfan 1565	. . 3 |- F/ x ( y Fn { x | x e. A } /\ A. x e. A ( y ` x ) e. B )
7	6	nfab 2324	. 2 |- F/_ x { y | ( y Fn { x | x e. A } /\ A. x e. A ( y ` x ) e. B ) }
8	1, 7	nfcxfr 2316	1 |- F/_ x X_ x e. A B

Syntax hints:   /\ wa 104   e. wcel 2148   {cab 2163   F/_wnfc 2306   A.wral 2455   Fn wfn 5212   ` cfv 5217   X_cixp 6698

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-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159

This theorem depends on definitions:  df-bi 117  df-3an 980  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ral 2460  df-v 2740  df-un 3134  df-in 3136  df-ss 3143  df-sn 3599  df-pr 3600  df-op 3602  df-br 4005  df-opab 4066  df-rel 4634  df-cnv 4635  df-co 4636  df-dm 4637  df-fun 5219  df-fn 5220  df-ixp 6699

This theorem is referenced by: (None)