Theorem nffo 5479

Description: Bound-variable hypothesis builder for an onto function. (Contributed by NM, 16-May-2004.)

Hypotheses

Ref	Expression
nffo.1	|- F/_ x F
nffo.2	|- F/_ x A
nffo.3	|- F/_ x B

Assertion

Ref	Expression
nffo	|- F/ x F : A -onto-> B

Proof of Theorem nffo

Step	Hyp	Ref	Expression
1		df-fo 5264	. 2 |- ( F : A -onto-> B <-> ( F Fn A /\ ran F = B ) )
2		nffo.1	. . . 4 |- F/_ x F
3		nffo.2	. . . 4 |- F/_ x A
4	2, 3	nffn 5354	. . 3 |- F/ x F Fn A
5	2	nfrn 4911	. . . 4 |- F/_ x ran F
6		nffo.3	. . . 4 |- F/_ x B
7	5, 6	nfeq 2347	. . 3 |- F/ x ran F = B
8	4, 7	nfan 1579	. 2 |- F/ x ( F Fn A /\ ran F = B )
9	1, 8	nfxfr 1488	1 |- F/ x F : A -onto-> B

Syntax hints:   /\ wa 104   = wceq 1364   F/wnf 1474   F/_wnfc 2326   ran crn 4664   Fn wfn 5253   -onto->wfo 5256

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 710  ax-5 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-10 1519  ax-11 1520  ax-i12 1521  ax-bndl 1523  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-ext 2178

This theorem depends on definitions:  df-bi 117  df-3an 982  df-tru 1367  df-nf 1475  df-sb 1777  df-clab 2183  df-cleq 2189  df-clel 2192  df-nfc 2328  df-ral 2480  df-v 2765  df-un 3161  df-in 3163  df-ss 3170  df-sn 3628  df-pr 3629  df-op 3631  df-br 4034  df-opab 4095  df-rel 4670  df-cnv 4671  df-co 4672  df-dm 4673  df-rn 4674  df-fun 5260  df-fn 5261  df-fo 5264

This theorem is referenced by:  nff1o  5502  ctiunctal  12658