User 喻良 - MathOverflow

37 votes

Accepted

Can one cover the plane with less than continuum of lines?

answered Oct 22, 2013 at 7:09

17 votes

When will the real numbers be Borel?

answered Jun 10, 2018 at 15:50

12 votes

Accepted

Non null Turing antichain

answered Sep 22, 2015 at 1:43

11 votes

Partitioning $\mathbb{R}$ into $\aleph_1$ Borel sets

answered Nov 14, 2011 at 1:59

10 votes

Is it known how the Sigma Algebra generated by Jordan measurable sets compares to universally measurable sets and analytic sets?

answered Nov 20, 2018 at 0:36

9 votes

Is there a perfect set of ground model reals in the Cohen extension?

answered Oct 13, 2016 at 2:13

9 votes

Accepted

Borel Sets in Sacks Generic Extension

answered Jul 20, 2014 at 10:44

8 votes

Accepted

Sets computable from enough hints

answered Sep 29, 2014 at 0:57

8 votes

A "suitably generic" set of Cohen reals without forcing?

answered Jun 4, 2014 at 13:13

7 votes

Accepted

Martin's cone theorem and recursion theory

answered Apr 13, 2011 at 9:07

6 votes

Accepted

Martin-Löf randomness relative to a $\Delta^0_2$-representation of a real

answered Jun 18, 2014 at 8:58

6 votes

Borel cross section

answered Mar 10, 2015 at 17:59

6 votes

A G-delta-sigma that is not F-sigma?

answered May 22, 2011 at 8:41

5 votes

Connection between countable ordinals and Turing degrees

answered Nov 18, 2017 at 1:16

5 votes

Accepted

Is checking whether a compact $\Pi^0_1$-class is nonempty $\Sigma^1_1$-hard?

answered Nov 12, 2019 at 3:23

5 votes

Accepted

Double Posner-Robinson Join (or a cupping analog of minimal pair)

answered Apr 29, 2023 at 1:18

5 votes

Steinhaus theorem and Hausdorff dimension

answered Sep 1, 2023 at 5:43

4 votes

Accepted

$\Pi^0_2$ singleton forming minimal pair with $0''$

answered May 21, 2023 at 13:42

4 votes

Accepted

Degree of unsolvability of finding a open approximation to a Borel set, given its Borel code

answered Apr 4, 2015 at 18:43

4 votes

A compactness property for Borel sets

answered May 7, 2011 at 3:51

4 votes

Vitali Sets vs Bernstein Sets...

answered May 20, 2012 at 2:14

4 votes

To find an element of a $\Pi^1_1$ set

answered Jul 22, 2012 at 1:59

4 votes

Definition of HYP in $L_{\omega_1^{CK}}[a]$?

answered Jan 12, 2013 at 14:38

4 votes

Accepted

Analytic uniformization

answered Aug 7, 2013 at 11:06

3 votes

Probability that a Turing machine will nontrivially reduce a real

answered Apr 29, 2012 at 3:51

3 votes

Accepted

Are lightface \Delta-1-1 classes of reals describable with hyperarthmetic formulae?

answered Jul 23, 2014 at 11:16

3 votes

Accepted

Does every cuppable r.e. set cup with a low set?

answered Nov 12, 2021 at 1:59

3 votes

Is there a Borel subset of $ \mathbb{R}^{2} $, with finite vertical cross-sections, whose projection onto the first component is non-Borel?

answered Nov 19, 2016 at 4:21

3 votes

$\Delta^{1}_{2}$ and degrees of constructibility $\textbf{on sets}$

answered Oct 30, 2018 at 1:22

3 votes

Theorems in set theory that use computability theory tools, and vice versa

answered Apr 27, 2023 at 12:05

Stack Exchange Network

44 Answers

Can one cover the plane with less than continuum of lines?

When will the real numbers be Borel?

Non null Turing antichain

Partitioning $\mathbb{R}$ into $\aleph_1$ Borel sets

Is it known how the Sigma Algebra generated by Jordan measurable sets compares to universally measurable sets and analytic sets?

Is there a perfect set of ground model reals in the Cohen extension?

Borel Sets in Sacks Generic Extension

Sets computable from enough hints

A "suitably generic" set of Cohen reals without forcing?

Martin's cone theorem and recursion theory

Martin-Löf randomness relative to a $\Delta^0_2$-representation of a real

Borel cross section

A G-delta-sigma that is not F-sigma?

Connection between countable ordinals and Turing degrees

Is checking whether a compact $\Pi^0_1$-class is nonempty $\Sigma^1_1$-hard?

Double Posner-Robinson Join (or a cupping analog of minimal pair)

Steinhaus theorem and Hausdorff dimension

$\Pi^0_2$ singleton forming minimal pair with $0''$

Degree of unsolvability of finding a open approximation to a Borel set, given its Borel code

A compactness property for Borel sets

Vitali Sets vs Bernstein Sets...

To find an element of a $\Pi^1_1$ set

Definition of HYP in $L_{\omega_1^{CK}}[a]$?

Analytic uniformization

Probability that a Turing machine will nontrivially reduce a real

Are lightface \Delta-1-1 classes of reals describable with hyperarthmetic formulae?

Does every cuppable r.e. set cup with a low set?

Is there a Borel subset of $ \mathbb{R}^{2} $, with finite vertical cross-sections, whose projection onto the first component is non-Borel?

$\Delta^{1}_{2}$ and degrees of constructibility $\textbf{on sets}$

Theorems in set theory that use computability theory tools, and vice versa