Metamath Proof Explorer


Theorem sitmval

Description: Value of the simple function integral metric for a given space W and measure M . (Contributed by Thierry Arnoux, 30-Jan-2018)

Ref Expression
Hypotheses sitmval.d D=distW
sitmval.1 φWV
sitmval.2 φMranmeasures
Assertion sitmval φWsitmM=fMW,gMW𝑠*𝑠0+∞fDfgdM

Proof

Step Hyp Ref Expression
1 sitmval.d D=distW
2 sitmval.1 φWV
3 sitmval.2 φMranmeasures
4 elex WVWV
5 2 4 syl φWV
6 oveq1 w=Wwsitgm=Wsitgm
7 6 dmeqd w=Wmw=mW
8 fveq2 w=Wdistw=distW
9 8 ofeqd w=Wfdistw=fdistW
10 9 oveqd w=Wfdistwfg=fdistWfg
11 10 fveq2d w=W𝑠*𝑠0+∞fdistwfgdm=𝑠*𝑠0+∞fdistWfgdm
12 7 7 11 mpoeq123dv w=Wfmw,gmw𝑠*𝑠0+∞fdistwfgdm=fmW,gmW𝑠*𝑠0+∞fdistWfgdm
13 oveq2 m=MWsitgm=WsitgM
14 13 dmeqd m=MmW=MW
15 oveq2 m=M𝑠*𝑠0+∞sitgm=𝑠*𝑠0+∞sitgM
16 1 eqcomi distW=D
17 ofeq distW=DfdistW=fD
18 16 17 mp1i m=MfdistW=fD
19 18 oveqd m=MfdistWfg=fDfg
20 15 19 fveq12d m=M𝑠*𝑠0+∞fdistWfgdm=𝑠*𝑠0+∞fDfgdM
21 14 14 20 mpoeq123dv m=MfmW,gmW𝑠*𝑠0+∞fdistWfgdm=fMW,gMW𝑠*𝑠0+∞fDfgdM
22 df-sitm sitm=wV,mranmeasuresfmw,gmw𝑠*𝑠0+∞fdistwfgdm
23 ovex WsitgMV
24 23 dmex MWV
25 24 24 mpoex fMW,gMW𝑠*𝑠0+∞fDfgdMV
26 12 21 22 25 ovmpo WVMranmeasuresWsitmM=fMW,gMW𝑠*𝑠0+∞fDfgdM
27 5 3 26 syl2anc φWsitmM=fMW,gMW𝑠*𝑠0+∞fDfgdM