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Norbert
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I would like to know the answeranswers to the following questiontwo questions.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Denote $$ \mathscr{H}=\{\mathcal{H}\subset 2^M: \mathcal{H}\mbox{ is a disjoint family of Borel sets of positive measure}\} $$ Note that for measures with the continuous part or infinitely many atoms there is an infinite family $\mathcal{H}\in\mathscr{H}$.

Question #1. Does there exist an infinite disjoint family of Borel sets $\mathcal{H}$$\mathcal{H}\in\mathscr{H}$ such that for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ have positive measure intersection with $K$?

  • every element of $\mathcal{H}$ has positive measure and sits inside $M$;
  • for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ intersect $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.

Maybe it would be easier to characterize measures with the opposite property.

Question #2. What can we say about $S$ or $\mu$ if for any countable $\mathcal{H}\in \mathscr{H}$ there exists a compact $K$ such that infinitely many elements of $\mathcal{H}$ have positive measure intersection with $K$.

It looks like these questions fit well into the realm of measure algebras but I don't know much about them.

I would like to know the answer to the following question.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Does there exist an infinite disjoint family of Borel sets $\mathcal{H}$ such that

  • every element of $\mathcal{H}$ has positive measure and sits inside $M$;
  • for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ intersect $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.

I would like to know the answers to the following two questions.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Denote $$ \mathscr{H}=\{\mathcal{H}\subset 2^M: \mathcal{H}\mbox{ is a disjoint family of Borel sets of positive measure}\} $$ Note that for measures with the continuous part or infinitely many atoms there is an infinite family $\mathcal{H}\in\mathscr{H}$.

Question #1. Does there exist an infinite family $\mathcal{H}\in\mathscr{H}$ such that for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ have positive measure intersection with $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.

Maybe it would be easier to characterize measures with the opposite property.

Question #2. What can we say about $S$ or $\mu$ if for any countable $\mathcal{H}\in \mathscr{H}$ there exists a compact $K$ such that infinitely many elements of $\mathcal{H}$ have positive measure intersection with $K$.

It looks like these questions fit well into the realm of measure algebras but I don't know much about them.

deleted 5 characters in body
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Norbert
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I would like to know the answer to the following question.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Does there exist an infinite disjoint family of Borel sets $\mathcal{H}$ such that

  • every element of $\mathcal{H}$ has positive measure and sits inside $M$;
  • for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ intersect with $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.

I would like to know the answer to the following question.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Does there exist an infinite disjoint family of Borel sets $\mathcal{H}$ such that

  • every element of $\mathcal{H}$ has positive measure and sits inside $M$;
  • for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ intersect with $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.

I would like to know the answer to the following question.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Does there exist an infinite disjoint family of Borel sets $\mathcal{H}$ such that

  • every element of $\mathcal{H}$ has positive measure and sits inside $M$;
  • for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ intersect $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.
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Norbert
  • 1.7k
  • 14
  • 27

Measure support decomposition that "tends to infinity"

I would like to know the answer to the following question.

Let $S$ be a locally compact Hausdorff space, $\mu$ be a regular Borel measure with non-compact support $M$. Does there exist an infinite disjoint family of Borel sets $\mathcal{H}$ such that

  • every element of $\mathcal{H}$ has positive measure and sits inside $M$;
  • for any compact $K\subset M$ only finitely many elements of $\mathcal{H}$ intersect with $K$?

A few side notes:

  • I know, how to prove this in the case where $S$ is $\sigma$-compact;
  • There is an obvious example without $\sigma$-compactness - counting measure on an uncountable set;
  • From [342B, Measure theory. Vol 3. Measure algebras. D. H. Fremlin] I know how to construct at most countable disjoint family $\mathcal{H}$ consisting of compacts of positive measure.