Under which assumptions are two Borel measures equal?












2












$begingroup$


Assume $(X,tau)$ is a topological space and $mathcal B (X)$ the corresponding Borel $sigma$-Algebra. Let $mu$ and $nu$ be two Borel measures on $mathcal B (X)$. Now let $Q$ be some set of measurable functions $f : X to mathbb C$.



Under which (minimal) assumptions on the topology $tau$ or the set $Q$ can we conclude that from



$$
int_X f , dmu = int_X f , dnu forall f in Q
$$



follows $mu = nu$?










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$endgroup$












  • $begingroup$
    You must be able to approximate every measurable set by elements in $Q$.
    $endgroup$
    – Yanko
    Feb 2 at 13:43












  • $begingroup$
    If $Q$ contain unitary function of open set, then $mu=nu$. Is it the minimal condition ? I'm not really sure.
    $endgroup$
    – idm
    Feb 2 at 13:46






  • 2




    $begingroup$
    The classical case is $X$ locally compact Hausdorff and $Q$ all continuous (real) functions. This is Riesz duality in essence.
    $endgroup$
    – Henno Brandsma
    Feb 2 at 15:42










  • $begingroup$
    Can we also replace the set of all continuous functions by a dense subset and still argue with Riesz?
    $endgroup$
    – Muzi
    Feb 2 at 18:02
















2












$begingroup$


Assume $(X,tau)$ is a topological space and $mathcal B (X)$ the corresponding Borel $sigma$-Algebra. Let $mu$ and $nu$ be two Borel measures on $mathcal B (X)$. Now let $Q$ be some set of measurable functions $f : X to mathbb C$.



Under which (minimal) assumptions on the topology $tau$ or the set $Q$ can we conclude that from



$$
int_X f , dmu = int_X f , dnu forall f in Q
$$



follows $mu = nu$?










share|cite|improve this question









$endgroup$












  • $begingroup$
    You must be able to approximate every measurable set by elements in $Q$.
    $endgroup$
    – Yanko
    Feb 2 at 13:43












  • $begingroup$
    If $Q$ contain unitary function of open set, then $mu=nu$. Is it the minimal condition ? I'm not really sure.
    $endgroup$
    – idm
    Feb 2 at 13:46






  • 2




    $begingroup$
    The classical case is $X$ locally compact Hausdorff and $Q$ all continuous (real) functions. This is Riesz duality in essence.
    $endgroup$
    – Henno Brandsma
    Feb 2 at 15:42










  • $begingroup$
    Can we also replace the set of all continuous functions by a dense subset and still argue with Riesz?
    $endgroup$
    – Muzi
    Feb 2 at 18:02














2












2








2





$begingroup$


Assume $(X,tau)$ is a topological space and $mathcal B (X)$ the corresponding Borel $sigma$-Algebra. Let $mu$ and $nu$ be two Borel measures on $mathcal B (X)$. Now let $Q$ be some set of measurable functions $f : X to mathbb C$.



Under which (minimal) assumptions on the topology $tau$ or the set $Q$ can we conclude that from



$$
int_X f , dmu = int_X f , dnu forall f in Q
$$



follows $mu = nu$?










share|cite|improve this question









$endgroup$




Assume $(X,tau)$ is a topological space and $mathcal B (X)$ the corresponding Borel $sigma$-Algebra. Let $mu$ and $nu$ be two Borel measures on $mathcal B (X)$. Now let $Q$ be some set of measurable functions $f : X to mathbb C$.



Under which (minimal) assumptions on the topology $tau$ or the set $Q$ can we conclude that from



$$
int_X f , dmu = int_X f , dnu forall f in Q
$$



follows $mu = nu$?







integration general-topology analysis measure-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Feb 2 at 13:36









MuziMuzi

453320




453320












  • $begingroup$
    You must be able to approximate every measurable set by elements in $Q$.
    $endgroup$
    – Yanko
    Feb 2 at 13:43












  • $begingroup$
    If $Q$ contain unitary function of open set, then $mu=nu$. Is it the minimal condition ? I'm not really sure.
    $endgroup$
    – idm
    Feb 2 at 13:46






  • 2




    $begingroup$
    The classical case is $X$ locally compact Hausdorff and $Q$ all continuous (real) functions. This is Riesz duality in essence.
    $endgroup$
    – Henno Brandsma
    Feb 2 at 15:42










  • $begingroup$
    Can we also replace the set of all continuous functions by a dense subset and still argue with Riesz?
    $endgroup$
    – Muzi
    Feb 2 at 18:02


















  • $begingroup$
    You must be able to approximate every measurable set by elements in $Q$.
    $endgroup$
    – Yanko
    Feb 2 at 13:43












  • $begingroup$
    If $Q$ contain unitary function of open set, then $mu=nu$. Is it the minimal condition ? I'm not really sure.
    $endgroup$
    – idm
    Feb 2 at 13:46






  • 2




    $begingroup$
    The classical case is $X$ locally compact Hausdorff and $Q$ all continuous (real) functions. This is Riesz duality in essence.
    $endgroup$
    – Henno Brandsma
    Feb 2 at 15:42










  • $begingroup$
    Can we also replace the set of all continuous functions by a dense subset and still argue with Riesz?
    $endgroup$
    – Muzi
    Feb 2 at 18:02
















$begingroup$
You must be able to approximate every measurable set by elements in $Q$.
$endgroup$
– Yanko
Feb 2 at 13:43






$begingroup$
You must be able to approximate every measurable set by elements in $Q$.
$endgroup$
– Yanko
Feb 2 at 13:43














$begingroup$
If $Q$ contain unitary function of open set, then $mu=nu$. Is it the minimal condition ? I'm not really sure.
$endgroup$
– idm
Feb 2 at 13:46




$begingroup$
If $Q$ contain unitary function of open set, then $mu=nu$. Is it the minimal condition ? I'm not really sure.
$endgroup$
– idm
Feb 2 at 13:46




2




2




$begingroup$
The classical case is $X$ locally compact Hausdorff and $Q$ all continuous (real) functions. This is Riesz duality in essence.
$endgroup$
– Henno Brandsma
Feb 2 at 15:42




$begingroup$
The classical case is $X$ locally compact Hausdorff and $Q$ all continuous (real) functions. This is Riesz duality in essence.
$endgroup$
– Henno Brandsma
Feb 2 at 15:42












$begingroup$
Can we also replace the set of all continuous functions by a dense subset and still argue with Riesz?
$endgroup$
– Muzi
Feb 2 at 18:02




$begingroup$
Can we also replace the set of all continuous functions by a dense subset and still argue with Riesz?
$endgroup$
– Muzi
Feb 2 at 18:02










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