User Daniel Schepler - Mathematics Stack Exchange

14 votes

5 answers

295 views

Assume $\alpha, \beta \in \Bbb C,$ such that $\alpha^m = \beta^n = 1$ show that $(\alpha+\beta)^{mn}\in \Bbb R$

asked Oct 19, 2017 at 21:42

14 votes

2 answers

264 views

Is the Rubik's Cube group normal in the assembly/disassembly group?

asked May 8, 2023 at 19:16

10 votes

2 answers

155 views

If $\sum_n \frac{1}{a_n} = 2$ where $a_n$ are positive integers, is there a subset such that $\sum_{n\in S} \frac{1}{a_n} = 1$? [duplicate]

asked Apr 21, 2022 at 18:11

9 votes

0 answers

148 views

Do free modules exist in a general topos?

asked Oct 10, 2022 at 22:22

9 votes

1 answer

549 views

Is is possible to double the cube using compass, straightedge, and angle trisector?

asked Sep 15, 2017 at 23:55

8 votes

2 answers

164 views

Functional equation: $f(x)f(y)$ is radially symmetric

asked Sep 4, 2016 at 17:01

6 votes

1 answer

447 views

Does a real closed field satisfy the mean value theorem for polynomials?

asked Nov 30, 2017 at 0:17

6 votes

1 answer

637 views

Example of a complex function with "essential singularity" all along the unit circle

asked Jun 18, 2019 at 19:57

5 votes

0 answers

63 views

Is there an intuitionistic proof of "it is impossible to simulate a die with a guaranteed to terminate process involving coin flips"?

asked Oct 24, 2020 at 21:08

5 votes

0 answers

127 views

On a certain "anticurl" operator

asked Mar 3, 2023 at 17:55

5 votes

2 answers

97 views

Equivalence of two definitions of sheaves over a Lawvere-Tierney topology

asked Apr 8, 2023 at 17:03

4 votes

1 answer

153 views

Is there a topos of Heyting algebra valued models?

asked Aug 4, 2022 at 18:45

4 votes

0 answers

62 views

Which functors between varieties of algebras are monadic?

asked Aug 22, 2018 at 23:03

3 votes

0 answers

79 views

Is intuitionistic first-order logic with no function or relation symbols decidable?

asked Apr 11, 2019 at 19:24

3 votes

1 answer

372 views

Does the internal logic of a topos satisfy propositional, functional, set extensionality?

asked Apr 29, 2017 at 15:26

3 votes

1 answer

287 views

Which "limit of ultrafilter" functions induce a compact Hausdorff topological structure?

asked Jun 5, 2017 at 23:41

3 votes

3 answers

175 views

Abstracting the general forcing argument from case-specific arguments

asked Mar 10, 2020 at 18:49

3 votes

1 answer

54 views

Conjecture: The $n$th left Riemann sum for $\int_0^1 (x-x^2)^k dx$ is $B(k+1,k+1) + \Theta(n^{-2 \lceil (k+1)/2\rceil})$

asked May 8 at 0:31

2 votes

1 answer

190 views

Is the fundamental theorem of algebra true for constructive complex numbers?

asked Oct 13, 2023 at 0:23

2 votes

1 answer

84 views

In intuitionistic FOL, does $\forall x \forall y (P(x) \lor Q(y))$ imply $(\forall x, P(x)) \lor (\forall y, Q(y))$?

asked Feb 16, 2023 at 17:58

2 votes

0 answers

32 views

Is there a name for the fragment of (typed) first-order logic which works "pointwise" in any topos?

asked Jun 1, 2020 at 17:37

2 votes

1 answer

121 views

Is there any standardized "practical extension" language for ZFC?

asked Sep 24, 2019 at 21:58

2 votes

1 answer

91 views

In $\mathbb{C}[a_{11}, \ldots, a_{nn}, b_{11}, \ldots, b_{nn}]$, is $\langle AB - I_n \rangle = \langle BA - I_n \rangle$?

asked Feb 20, 2020 at 19:07

2 votes

2 answers

265 views

Relation between positive correlation and $p(Y_2 > Y_1 \mid X_2 > X_1) > \frac{1}{2}$?

asked Jul 27, 2017 at 17:40

2 votes

1 answer

178 views

What quadratic field is contained in the splitting field of $x^5 - 4x - 2$ over $\mathbb{Q}$?

asked Dec 11, 2017 at 20:14

2 votes

1 answer

44 views

Which polynomials in $\mathbb{F}_p[x,y,z]$ evaluate to 0 at all points of $\mathbb{F}_p^3$?

asked Oct 13, 2017 at 18:02

2 votes

3 answers

111 views

True or false: if $(a_n)_{n=1}^\infty \subseteq \{ -1, 1 \}$ then almost certainly $\sum_{n=1}^\infty \frac{a_n}{n}$ converges

asked Feb 9, 2018 at 20:41

1 vote

0 answers

16 views

Proof verification: Group of units functor is not monadic

asked Aug 16, 2018 at 17:49

1 vote

0 answers

35 views

Proof verification: $+\infty$ is not a point of the topos $\mathbb{R}$

asked Aug 27, 2019 at 19:35

1 vote

1 answer

36 views

If $f$ is continuous and $f(x)$ has no cluster points as $x \to b^-$ then $f(x) \to \infty$ or $f(x) \to -\infty$ as $x \to b^-$

asked Jan 4, 2018 at 19:15

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35 Questions

Assume $\alpha, \beta \in \Bbb C,$ such that $\alpha^m = \beta^n = 1$ show that $(\alpha+\beta)^{mn}\in \Bbb R$

Is the Rubik's Cube group normal in the assembly/disassembly group?

If $\sum_n \frac{1}{a_n} = 2$ where $a_n$ are positive integers, is there a subset such that $\sum_{n\in S} \frac{1}{a_n} = 1$? [duplicate]

Do free modules exist in a general topos?

Is is possible to double the cube using compass, straightedge, and angle trisector?

Functional equation: $f(x)f(y)$ is radially symmetric

Does a real closed field satisfy the mean value theorem for polynomials?

Example of a complex function with "essential singularity" all along the unit circle

Is there an intuitionistic proof of "it is impossible to simulate a die with a guaranteed to terminate process involving coin flips"?

On a certain "anticurl" operator

Equivalence of two definitions of sheaves over a Lawvere-Tierney topology

Is there a topos of Heyting algebra valued models?

Which functors between varieties of algebras are monadic?

Is intuitionistic first-order logic with no function or relation symbols decidable?

Does the internal logic of a topos satisfy propositional, functional, set extensionality?

Which "limit of ultrafilter" functions induce a compact Hausdorff topological structure?

Abstracting the general forcing argument from case-specific arguments

Conjecture: The $n$th left Riemann sum for $\int_0^1 (x-x^2)^k dx$ is $B(k+1,k+1) + \Theta(n^{-2 \lceil (k+1)/2\rceil})$

Is the fundamental theorem of algebra true for constructive complex numbers?

In intuitionistic FOL, does $\forall x \forall y (P(x) \lor Q(y))$ imply $(\forall x, P(x)) \lor (\forall y, Q(y))$?

Is there a name for the fragment of (typed) first-order logic which works "pointwise" in any topos?

Is there any standardized "practical extension" language for ZFC?

In $\mathbb{C}[a_{11}, \ldots, a_{nn}, b_{11}, \ldots, b_{nn}]$, is $\langle AB - I_n \rangle = \langle BA - I_n \rangle$?

Relation between positive correlation and $p(Y_2 > Y_1 \mid X_2 > X_1) > \frac{1}{2}$?

What quadratic field is contained in the splitting field of $x^5 - 4x - 2$ over $\mathbb{Q}$?

Which polynomials in $\mathbb{F}_p[x,y,z]$ evaluate to 0 at all points of $\mathbb{F}_p^3$?

True or false: if $(a_n)_{n=1}^\infty \subseteq \{ -1, 1 \}$ then almost certainly $\sum_{n=1}^\infty \frac{a_n}{n}$ converges

Proof verification: Group of units functor is not monadic

Proof verification: $+\infty$ is not a point of the topos $\mathbb{R}$

If $f$ is continuous and $f(x)$ has no cluster points as $x \to b^-$ then $f(x) \to \infty$ or $f(x) \to -\infty$ as $x \to b^-$