User Salvo Tringali

33 votes

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How Composite can $2^n-1$ be, infinitely often?

answered Oct 16, 2017 at 7:12

27 votes

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Sums of sets of lower density 0

answered May 6, 2015 at 8:53

18 votes

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Sets that are not sum of subsets

answered Oct 31, 2021 at 16:17

13 votes

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Polynomials leaving invariant the Gaussian integers

answered Jul 24, 2017 at 5:08

12 votes

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Is there any non-commutative ring such that every element other than the identity is a zero divisor?

answered Jun 20, 2021 at 16:35

12 votes

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On the origin of a fundamental theorem of additive number theory

answered Aug 9 at 15:52

12 votes

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Approximating integers with prime quotients

answered Sep 22, 2015 at 7:51

10 votes

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Sums of two squares: positive lower density?

answered May 6, 2015 at 12:54

8 votes

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Irreducible elements in endomorphism rings

answered Mar 8, 2017 at 9:01

8 votes

$\zeta^{(k)}(s) < 0$ for $s\in (0,1)$

answered Oct 29, 2017 at 22:26

7 votes

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A result of Sierpiński on non-atomic measures

answered Nov 10, 2015 at 21:12

7 votes

How to cite authors from any country correctly?

answered Feb 13, 2016 at 23:56

6 votes

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About Euclidean domains

answered Mar 11, 2017 at 22:22

6 votes

sum-sets in a finite field

answered Mar 22, 2017 at 19:43

6 votes

Perturbation theory for the generalized eigenvalue problem

answered Jun 4, 2012 at 18:18

6 votes

Applications of Liouville's theorem

answered Jun 27, 2012 at 9:35

6 votes

Open problems with monetary rewards

answered May 2, 2017 at 11:25

6 votes

What are the main structure theorems on finitely generated commutative monoids?

answered Jan 26, 2022 at 11:50

5 votes

Is there some example that nicely extends the multiplication of natural numbers?

answered Feb 12, 2022 at 20:49

5 votes

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A name for semigroups in which left and right principal ideals coincide

answered Feb 20, 2022 at 22:20

5 votes

Does $R$ is Dedekind-finite imply $\mathbb{M}_n(R)$ is Dedekind-finite

answered Sep 7, 2022 at 16:51

5 votes

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What is the derivative of $1/g$ in a differential semiring?

answered Dec 24, 2020 at 16:30

5 votes

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On a generalization of the classical Cauchy's functional equation

answered Mar 9, 2017 at 19:17

5 votes

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How composite $a^n+b$ is?

answered Oct 28, 2017 at 16:39

5 votes

Dihedral extensions and the Ankeny–Artin–Chowla conjecture

answered Nov 2 at 7:57

4 votes

Conjecture about commutative semigroups

answered Oct 11 at 3:20

4 votes

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For which abelian groups $G$ does the monoid of zero-sum sequences over $G$ embed into a ring as a divisor-closed subsemigroup?

answered Jul 27, 2017 at 23:15

4 votes

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Cartesian products and set-products

answered Jun 16, 2021 at 20:51

4 votes

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Maximal zero-sum free sequences of $C_3^n$

answered Aug 27 at 6:42

3 votes

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Is every cancellative semigroup a subdirect product of subdirectly irreducible cancellative semigroups?

answered Oct 9 at 16:17

Stack Exchange Network

77 Answers

How Composite can $2^n-1$ be, infinitely often?

Sums of sets of lower density 0

Sets that are not sum of subsets

Polynomials leaving invariant the Gaussian integers

Is there any non-commutative ring such that every element other than the identity is a zero divisor?

On the origin of a fundamental theorem of additive number theory

Approximating integers with prime quotients

Sums of two squares: positive lower density?

Irreducible elements in endomorphism rings

$\zeta^{(k)}(s) < 0$ for $s\in (0,1)$

A result of Sierpiński on non-atomic measures

How to cite authors from any country correctly?

About Euclidean domains

sum-sets in a finite field

Perturbation theory for the generalized eigenvalue problem

Applications of Liouville's theorem

Open problems with monetary rewards

What are the main structure theorems on finitely generated commutative monoids?

Is there some example that nicely extends the multiplication of natural numbers?

A name for semigroups in which left and right principal ideals coincide

Does $R$ is Dedekind-finite imply $\mathbb{M}_n(R)$ is Dedekind-finite

What is the derivative of $1/g$ in a differential semiring?

On a generalization of the classical Cauchy's functional equation

How composite $a^n+b$ is?

Dihedral extensions and the Ankeny–Artin–Chowla conjecture

Conjecture about commutative semigroups

For which abelian groups $G$ does the monoid of zero-sum sequences over $G$ embed into a ring as a divisor-closed subsemigroup?

Cartesian products and set-products

Maximal zero-sum free sequences of $C_3^n$

Is every cancellative semigroup a subdirect product of subdirectly irreducible cancellative semigroups?