Metamath Proof Explorer


Theorem bnj1520

Description: Technical lemma for bnj1500 . This lemma may no longer be used or have become an indirect lemma of the theorem in question (i.e. a lemma of a lemma... of the theorem). (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypotheses bnj1520.1 B = d | d A x d pred x A R d
bnj1520.2 Y = x f pred x A R
bnj1520.3 C = f | d B f Fn d x d f x = G Y
bnj1520.4 F = C
Assertion bnj1520 F x = G x F pred x A R f F x = G x F pred x A R

Proof

Step Hyp Ref Expression
1 bnj1520.1 B = d | d A x d pred x A R d
2 bnj1520.2 Y = x f pred x A R
3 bnj1520.3 C = f | d B f Fn d x d f x = G Y
4 bnj1520.4 F = C
5 3 bnj1317 w C f w C
6 5 nfcii _ f C
7 6 nfuni _ f C
8 4 7 nfcxfr _ f F
9 nfcv _ f x
10 8 9 nffv _ f F x
11 nfcv _ f G
12 nfcv _ f pred x A R
13 8 12 nfres _ f F pred x A R
14 9 13 nfop _ f x F pred x A R
15 11 14 nffv _ f G x F pred x A R
16 10 15 nfeq f F x = G x F pred x A R
17 16 nf5ri F x = G x F pred x A R f F x = G x F pred x A R