Metamath Proof Explorer


Theorem smfpimcc

Description: Given a countable set of sigma-measurable functions, and a Borel set A there exists a choice function h that, for each measurable function, chooses a measurable set that, when intersected with the function's domain, gives the preimage of A . This is a generalization of the observation at the beginning of the proof of Proposition 121F of Fremlin1 p. 39 . The statement would also be provable for uncountable sets, but in most cases it will suffice to consider the countable case, and only the axiom of countable choice will be needed. (Contributed by Glauco Siliprandi, 23-Oct-2021)

Ref Expression
Hypotheses smfpimcc.1 _nF
smfpimcc.z Z=M
smfpimcc.s φSSAlg
smfpimcc.f φF:ZSMblFnS
smfpimcc.j J=topGenran.
smfpimcc.b B=SalGenJ
smfpimcc.a φAB
Assertion smfpimcc φhh:ZSnZFn-1A=hndomFn

Proof

Step Hyp Ref Expression
1 smfpimcc.1 _nF
2 smfpimcc.z Z=M
3 smfpimcc.s φSSAlg
4 smfpimcc.f φF:ZSMblFnS
5 smfpimcc.j J=topGenran.
6 smfpimcc.b B=SalGenJ
7 smfpimcc.a φAB
8 2 uzct Zω
9 8 a1i φZω
10 mptct ZωmZsS|Fm-1A=sdomFmω
11 rnct mZsS|Fm-1A=sdomFmωranmZsS|Fm-1A=sdomFmω
12 9 10 11 3syl φranmZsS|Fm-1A=sdomFmω
13 vex yV
14 eqid mZsS|Fm-1A=sdomFm=mZsS|Fm-1A=sdomFm
15 14 elrnmpt yVyranmZsS|Fm-1A=sdomFmmZy=sS|Fm-1A=sdomFm
16 13 15 ax-mp yranmZsS|Fm-1A=sdomFmmZy=sS|Fm-1A=sdomFm
17 16 biimpi yranmZsS|Fm-1A=sdomFmmZy=sS|Fm-1A=sdomFm
18 17 adantl φyranmZsS|Fm-1A=sdomFmmZy=sS|Fm-1A=sdomFm
19 simp3 φmZy=sS|Fm-1A=sdomFmy=sS|Fm-1A=sdomFm
20 3 adantr φmZSSAlg
21 4 ffvelcdmda φmZFmSMblFnS
22 eqid domFm=domFm
23 7 adantr φmZAB
24 eqid Fm-1A=Fm-1A
25 20 21 22 5 6 23 24 smfpimbor1 φmZFm-1AS𝑡domFm
26 fvex FmV
27 26 dmex domFmV
28 27 a1i φdomFmV
29 elrest SSAlgdomFmVFm-1AS𝑡domFmsSFm-1A=sdomFm
30 3 28 29 syl2anc φFm-1AS𝑡domFmsSFm-1A=sdomFm
31 30 adantr φmZFm-1AS𝑡domFmsSFm-1A=sdomFm
32 25 31 mpbid φmZsSFm-1A=sdomFm
33 rabn0 sS|Fm-1A=sdomFmsSFm-1A=sdomFm
34 32 33 sylibr φmZsS|Fm-1A=sdomFm
35 34 3adant3 φmZy=sS|Fm-1A=sdomFmsS|Fm-1A=sdomFm
36 19 35 eqnetrd φmZy=sS|Fm-1A=sdomFmy
37 36 3exp φmZy=sS|Fm-1A=sdomFmy
38 37 rexlimdv φmZy=sS|Fm-1A=sdomFmy
39 38 adantr φyranmZsS|Fm-1A=sdomFmmZy=sS|Fm-1A=sdomFmy
40 18 39 mpd φyranmZsS|Fm-1A=sdomFmy
41 12 40 axccd2 φfyranmZsS|Fm-1A=sdomFmfyy
42 nfv mφ
43 nfmpt1 _mmZsS|Fm-1A=sdomFm
44 43 nfrn _mranmZsS|Fm-1A=sdomFm
45 nfv mfyy
46 44 45 nfralw myranmZsS|Fm-1A=sdomFmfyy
47 42 46 nfan mφyranmZsS|Fm-1A=sdomFmfyy
48 2 fvexi ZV
49 3 adantr φyranmZsS|Fm-1A=sdomFmfyySSAlg
50 fveq2 y=wfy=fw
51 id y=wy=w
52 50 51 eleq12d y=wfyyfww
53 52 rspccva yranmZsS|Fm-1A=sdomFmfyywranmZsS|Fm-1A=sdomFmfww
54 53 adantll φyranmZsS|Fm-1A=sdomFmfyywranmZsS|Fm-1A=sdomFmfww
55 eqid mZfsS|Fm-1A=sdomFm=mZfsS|Fm-1A=sdomFm
56 47 48 49 54 55 smfpimcclem φyranmZsS|Fm-1A=sdomFmfyyhh:ZSmZFm-1A=hmdomFm
57 56 ex φyranmZsS|Fm-1A=sdomFmfyyhh:ZSmZFm-1A=hmdomFm
58 57 exlimdv φfyranmZsS|Fm-1A=sdomFmfyyhh:ZSmZFm-1A=hmdomFm
59 41 58 mpd φhh:ZSmZFm-1A=hmdomFm
60 nfcv _nm
61 1 60 nffv _nFm
62 61 nfcnv _nFm-1
63 nfcv _nA
64 62 63 nfima _nFm-1A
65 nfcv _nhm
66 61 nfdm _ndomFm
67 65 66 nfin _nhmdomFm
68 64 67 nfeq nFm-1A=hmdomFm
69 nfv mFn-1A=hndomFn
70 fveq2 m=nFm=Fn
71 70 cnveqd m=nFm-1=Fn-1
72 71 imaeq1d m=nFm-1A=Fn-1A
73 fveq2 m=nhm=hn
74 70 dmeqd m=ndomFm=domFn
75 73 74 ineq12d m=nhmdomFm=hndomFn
76 72 75 eqeq12d m=nFm-1A=hmdomFmFn-1A=hndomFn
77 68 69 76 cbvralw mZFm-1A=hmdomFmnZFn-1A=hndomFn
78 77 anbi2i h:ZSmZFm-1A=hmdomFmh:ZSnZFn-1A=hndomFn
79 78 exbii hh:ZSmZFm-1A=hmdomFmhh:ZSnZFn-1A=hndomFn
80 59 79 sylib φhh:ZSnZFn-1A=hndomFn