User KP Hart

30 votes

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Sets with positive Lebesgue measure boundary

answered May 26, 2010 at 12:19

23 votes

What are examples of mathematical concepts named after the wrong people? (Stigler's law)

answered May 11, 2010 at 9:55

19 votes

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Is this question about US spaces still an open problem?

answered Oct 27, 2021 at 15:24

16 votes

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Is Stone-Čech compactification of 0-dimensional space also 0-dimensional?

answered Apr 11, 2012 at 12:34

16 votes

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Partition of unity without AC

answered May 17 at 8:36

15 votes

Is "compact implies sequentially compact" consistent with ZF?

answered Jun 23, 2010 at 11:07

14 votes

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Is "All hyperreal fields $C(\mathbb{R})/M$ are isomorphic" independent of ZFC+$\lnot$CH?

answered Aug 19, 2023 at 11:54

13 votes

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Mistake on article about Bohr compactification?

answered Dec 9 at 10:03

13 votes

What is your favorite proof of Tychonoff's Theorem?

answered May 30, 2010 at 14:41

13 votes

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Are k-spaces named for Kelley?

answered Apr 17, 2012 at 9:31

12 votes

Independent families of subsets of $\mathbb N$ of size continuum

answered Dec 14, 2010 at 11:54

12 votes

Does Urysohn's Lemma imply Dependent Choice?

answered Jan 23, 2023 at 17:30

11 votes

Fixed point theorem for the uncountable power of an interval

answered Dec 23, 2022 at 22:25

11 votes

"Transitivity" of the Stone-Cech compactification

answered May 12, 2010 at 8:10

11 votes

Which topological spaces admit a nonstandard metric?

answered May 31, 2010 at 8:57

10 votes

Does "compact iff projections are closed" require some form of choice?

answered Oct 19, 2010 at 14:07

10 votes

A "dimension" for Tychonoff spaces

answered Oct 19, 2011 at 19:42

10 votes

Zero-dimensional $F$-space which is not strongly zero-dimensional

answered Jul 27, 2021 at 14:13

10 votes

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Characterization of pretty compact spaces

answered Feb 5, 2021 at 12:56

10 votes

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$T_2$-spaces in which no two open sets are homeomorphic

answered Nov 1, 2018 at 11:07

10 votes

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Is there a metric compactification that doesn't create new paths?

answered Jul 6 at 15:45

10 votes

Countable chain condition in topology

answered Nov 27, 2023 at 20:08

10 votes

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What is the extent of a $\Sigma$-product of a (uncountable) power of a (countable) discrete space?

answered Apr 18 at 20:24

9 votes

Construction of nonmeasurable sets

answered Sep 15 at 12:07

9 votes

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Is it true that $\mathit{MA}(\omega_1)$ iff $\omega_1<\mathfrak{p}$?

answered Jan 15, 2023 at 10:00

9 votes

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Is the set of $\kappa$-complete ultrafilters closed in $\beta X$?

answered Oct 11, 2021 at 6:28

9 votes

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A strictly descending chain of subalgebras of $P(\omega)/_{\mathrm{fin}}$

answered Mar 8, 2023 at 10:05

9 votes

"Mächtigkeit" versus "Kardinalität"?

answered Oct 2, 2018 at 13:43

9 votes

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Why are free Boolean topological groups Hausdorff?

answered Jul 26, 2021 at 8:41

9 votes

Products of Baire spaces

answered May 13, 2010 at 19:01

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213 Answers

Sets with positive Lebesgue measure boundary

What are examples of mathematical concepts named after the wrong people? (Stigler's law)

Is this question about US spaces still an open problem?

Is Stone-Čech compactification of 0-dimensional space also 0-dimensional?

Partition of unity without AC

Is "compact implies sequentially compact" consistent with ZF?

Is "All hyperreal fields $C(\mathbb{R})/M$ are isomorphic" independent of ZFC+$\lnot$CH?

Mistake on article about Bohr compactification?

What is your favorite proof of Tychonoff's Theorem?

Are k-spaces named for Kelley?

Independent families of subsets of $\mathbb N$ of size continuum

Does Urysohn's Lemma imply Dependent Choice?

Fixed point theorem for the uncountable power of an interval

"Transitivity" of the Stone-Cech compactification

Which topological spaces admit a nonstandard metric?

Does "compact iff projections are closed" require some form of choice?

A "dimension" for Tychonoff spaces

Zero-dimensional $F$-space which is not strongly zero-dimensional

Characterization of pretty compact spaces

$T_2$-spaces in which no two open sets are homeomorphic

Is there a metric compactification that doesn't create new paths?

Countable chain condition in topology

What is the extent of a $\Sigma$-product of a (uncountable) power of a (countable) discrete space?

Construction of nonmeasurable sets

Is it true that $\mathit{MA}(\omega_1)$ iff $\omega_1<\mathfrak{p}$?

Is the set of $\kappa$-complete ultrafilters closed in $\beta X$?

A strictly descending chain of subalgebras of $P(\omega)/_{\mathrm{fin}}$

"Mächtigkeit" versus "Kardinalität"?

Why are free Boolean topological groups Hausdorff?

Products of Baire spaces