Problem 6. Barry Simon. A comprehensive course in analysis.











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Let $X$ compact Hausdorff space in wich every $left{xright}$ is a Baire set and let $mu$ be a Baire measure.
Define $mu_{pp}(A)=sum_{xin A}mu(left{xright})$



(a) Prove that $mu_{pp}$ is a pure point measure. I already proves!



(b) Prove that $mu_{c}:=mu-mu_{pp}$ is a nonnegative continuous measure.
I already prove!



(c)If $mu=nu_c+nu_{pp}$ with $nu_{pp}$ and $nu_{c}$ continuous, prove that $nu_{pp}=mu_{pp}$ and so $nu_{c}=mu_{c}$ (Correction. $nu_{pp}$ is a pure point)



How prove (c)?










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  • You have not quoted c) correctly. If $nu_c$ and $nu_{pp}$ are both continuous than $mu$ itself is continuous.
    – Kavi Rama Murthy
    Nov 21 at 5:43










  • oh! yes. $nu_{pp}$ is pure point
    – eraldcoil
    Nov 21 at 5:51















up vote
0
down vote

favorite












Let $X$ compact Hausdorff space in wich every $left{xright}$ is a Baire set and let $mu$ be a Baire measure.
Define $mu_{pp}(A)=sum_{xin A}mu(left{xright})$



(a) Prove that $mu_{pp}$ is a pure point measure. I already proves!



(b) Prove that $mu_{c}:=mu-mu_{pp}$ is a nonnegative continuous measure.
I already prove!



(c)If $mu=nu_c+nu_{pp}$ with $nu_{pp}$ and $nu_{c}$ continuous, prove that $nu_{pp}=mu_{pp}$ and so $nu_{c}=mu_{c}$ (Correction. $nu_{pp}$ is a pure point)



How prove (c)?










share|cite|improve this question
























  • You have not quoted c) correctly. If $nu_c$ and $nu_{pp}$ are both continuous than $mu$ itself is continuous.
    – Kavi Rama Murthy
    Nov 21 at 5:43










  • oh! yes. $nu_{pp}$ is pure point
    – eraldcoil
    Nov 21 at 5:51













up vote
0
down vote

favorite









up vote
0
down vote

favorite











Let $X$ compact Hausdorff space in wich every $left{xright}$ is a Baire set and let $mu$ be a Baire measure.
Define $mu_{pp}(A)=sum_{xin A}mu(left{xright})$



(a) Prove that $mu_{pp}$ is a pure point measure. I already proves!



(b) Prove that $mu_{c}:=mu-mu_{pp}$ is a nonnegative continuous measure.
I already prove!



(c)If $mu=nu_c+nu_{pp}$ with $nu_{pp}$ and $nu_{c}$ continuous, prove that $nu_{pp}=mu_{pp}$ and so $nu_{c}=mu_{c}$ (Correction. $nu_{pp}$ is a pure point)



How prove (c)?










share|cite|improve this question















Let $X$ compact Hausdorff space in wich every $left{xright}$ is a Baire set and let $mu$ be a Baire measure.
Define $mu_{pp}(A)=sum_{xin A}mu(left{xright})$



(a) Prove that $mu_{pp}$ is a pure point measure. I already proves!



(b) Prove that $mu_{c}:=mu-mu_{pp}$ is a nonnegative continuous measure.
I already prove!



(c)If $mu=nu_c+nu_{pp}$ with $nu_{pp}$ and $nu_{c}$ continuous, prove that $nu_{pp}=mu_{pp}$ and so $nu_{c}=mu_{c}$ (Correction. $nu_{pp}$ is a pure point)



How prove (c)?







functional-analysis measure-theory






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edited Nov 21 at 5:53

























asked Nov 21 at 5:32









eraldcoil

28119




28119












  • You have not quoted c) correctly. If $nu_c$ and $nu_{pp}$ are both continuous than $mu$ itself is continuous.
    – Kavi Rama Murthy
    Nov 21 at 5:43










  • oh! yes. $nu_{pp}$ is pure point
    – eraldcoil
    Nov 21 at 5:51


















  • You have not quoted c) correctly. If $nu_c$ and $nu_{pp}$ are both continuous than $mu$ itself is continuous.
    – Kavi Rama Murthy
    Nov 21 at 5:43










  • oh! yes. $nu_{pp}$ is pure point
    – eraldcoil
    Nov 21 at 5:51
















You have not quoted c) correctly. If $nu_c$ and $nu_{pp}$ are both continuous than $mu$ itself is continuous.
– Kavi Rama Murthy
Nov 21 at 5:43




You have not quoted c) correctly. If $nu_c$ and $nu_{pp}$ are both continuous than $mu$ itself is continuous.
– Kavi Rama Murthy
Nov 21 at 5:43












oh! yes. $nu_{pp}$ is pure point
– eraldcoil
Nov 21 at 5:51




oh! yes. $nu_{pp}$ is pure point
– eraldcoil
Nov 21 at 5:51










1 Answer
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up vote
2
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accepted










Let $C={x:mu {x} neq 0}$ and $D={x:nu_{pp} {x} neq 0}$, Verify the following for any measurable set $E$: $$nu_c(E)=nu_c(Esetminus Ccup D)=mu (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+mu_{pp} (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+0+0=mu_c(E).$$ This proves that $nu_c=mu_c$ and it follows automatically that $mu_{pp}=nu_{pp}$.






share|cite|improve this answer





















  • Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
    – eraldcoil
    Nov 25 at 7:33












  • @eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
    – Kavi Rama Murthy
    Nov 25 at 11:38










  • ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
    – eraldcoil
    Nov 25 at 21:27










  • @eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
    – Kavi Rama Murthy
    Nov 25 at 23:10











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1 Answer
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up vote
2
down vote



accepted










Let $C={x:mu {x} neq 0}$ and $D={x:nu_{pp} {x} neq 0}$, Verify the following for any measurable set $E$: $$nu_c(E)=nu_c(Esetminus Ccup D)=mu (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+mu_{pp} (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+0+0=mu_c(E).$$ This proves that $nu_c=mu_c$ and it follows automatically that $mu_{pp}=nu_{pp}$.






share|cite|improve this answer





















  • Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
    – eraldcoil
    Nov 25 at 7:33












  • @eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
    – Kavi Rama Murthy
    Nov 25 at 11:38










  • ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
    – eraldcoil
    Nov 25 at 21:27










  • @eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
    – Kavi Rama Murthy
    Nov 25 at 23:10















up vote
2
down vote



accepted










Let $C={x:mu {x} neq 0}$ and $D={x:nu_{pp} {x} neq 0}$, Verify the following for any measurable set $E$: $$nu_c(E)=nu_c(Esetminus Ccup D)=mu (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+mu_{pp} (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+0+0=mu_c(E).$$ This proves that $nu_c=mu_c$ and it follows automatically that $mu_{pp}=nu_{pp}$.






share|cite|improve this answer





















  • Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
    – eraldcoil
    Nov 25 at 7:33












  • @eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
    – Kavi Rama Murthy
    Nov 25 at 11:38










  • ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
    – eraldcoil
    Nov 25 at 21:27










  • @eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
    – Kavi Rama Murthy
    Nov 25 at 23:10













up vote
2
down vote



accepted







up vote
2
down vote



accepted






Let $C={x:mu {x} neq 0}$ and $D={x:nu_{pp} {x} neq 0}$, Verify the following for any measurable set $E$: $$nu_c(E)=nu_c(Esetminus Ccup D)=mu (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+mu_{pp} (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+0+0=mu_c(E).$$ This proves that $nu_c=mu_c$ and it follows automatically that $mu_{pp}=nu_{pp}$.






share|cite|improve this answer












Let $C={x:mu {x} neq 0}$ and $D={x:nu_{pp} {x} neq 0}$, Verify the following for any measurable set $E$: $$nu_c(E)=nu_c(Esetminus Ccup D)=mu (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+mu_{pp} (Esetminus Ccup D)-nu_{pp}(Esetminus Ccup D)$$ $$=mu_c (Esetminus Ccup D)+0+0=mu_c(E).$$ This proves that $nu_c=mu_c$ and it follows automatically that $mu_{pp}=nu_{pp}$.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Nov 21 at 6:03









Kavi Rama Murthy

44.7k31852




44.7k31852












  • Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
    – eraldcoil
    Nov 25 at 7:33












  • @eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
    – Kavi Rama Murthy
    Nov 25 at 11:38










  • ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
    – eraldcoil
    Nov 25 at 21:27










  • @eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
    – Kavi Rama Murthy
    Nov 25 at 23:10


















  • Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
    – eraldcoil
    Nov 25 at 7:33












  • @eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
    – Kavi Rama Murthy
    Nov 25 at 11:38










  • ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
    – eraldcoil
    Nov 25 at 21:27










  • @eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
    – Kavi Rama Murthy
    Nov 25 at 23:10
















Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
– eraldcoil
Nov 25 at 7:33






Why $mu_{pp}( (Esetminus C)cup D)=0$? I have this. Sup. $mu_{pp}( (Esetminus C)cup D)>0$ then exists $xin (Esetminus C)cup D$ such that $mu(x)>0$. If $xin Esetminus C$ then $xnotin C$, implies $mu(x)=0$ a contradiction. If $xin D.$ What is the contradiction?
– eraldcoil
Nov 25 at 7:33














@eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
– Kavi Rama Murthy
Nov 25 at 11:38




@eraldcoil By $Esetminus Ccup D$ I meant $Esetminus (Ccup D)$, not $(Esetminus C)cup D$
– Kavi Rama Murthy
Nov 25 at 11:38












ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
– eraldcoil
Nov 25 at 21:27




ah ok! thanks. I see $nu{pp}(Esetminus (Ccup D))=0$ but if $nu{pp}(Esetminus (Ccup D))>0$ then exits $xin Esetminus (Ccup D): nu_{pp}(x)>0$ a contradiction because $xin D^c$. Similary, $mu_{pp}(Esetminus (Ccup D))=0$. But I still do not see $nu_c(E)=nu_c(Esetminus (Ccup D))$
– eraldcoil
Nov 25 at 21:27












@eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
– Kavi Rama Murthy
Nov 25 at 23:10




@eraldcoil $C$ and $D$ are both countable sets and $nu_c$ is a continuous measure. Hence $nu_c(Ccup D)=0$.
– Kavi Rama Murthy
Nov 25 at 23:10


















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