Theorem nfixp1 6993

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 6974	. 2 |- X_ x e. A B = { y | ( y Fn { x | x e. A } /\ A. x e. A ( y ` x ) e. B ) }
2		nfcv 2392	. . . . 5 |- F/_ x y
3		nfab1 2394	. . . . 5 |- F/_ x { x | x e. A }
4	2, 3	nffn 5475	. . . 4 |- F/ x y Fn { x | x e. A }
5		nfra1 2581	. . . 4 |- F/ x A. x e. A ( y ` x ) e. B
6	4, 5	nfan 1618	. . 3 |- F/ x ( y Fn { x | x e. A } /\ A. x e. A ( y ` x ) e. B )
7	6	nfab 2397	. 2 |- F/_ x { y | ( y Fn { x | x e. A } /\ A. x e. A ( y ` x ) e. B ) }
8	1, 7	nfcxfr 2389	1 |- F/_ x X_ x e. A B

Syntax hints:   /\ wa 104   e. wcel 2209   {cab 2224   F/_wnfc 2379   A.wral 2528   Fn wfn 5370   ` cfv 5375   X_cixp 6973

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 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This theorem depends on definitions:  df-bi 117  df-3an 1011  df-tru 1405  df-nf 1514  df-sb 1816  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-ral 2533  df-v 2823  df-un 3224  df-in 3226  df-ss 3233  df-sn 3714  df-pr 3715  df-op 3717  df-br 4129  df-opab 4191  df-rel 4779  df-cnv 4780  df-co 4781  df-dm 4782  df-fun 5377  df-fn 5378  df-ixp 6974

This theorem is referenced by: (None)