User Jay

28 votes

Accepted

How can I prove that one of $n$, $n+2$, and $n+4$ must be divisible by three, for any $n\in\mathbb{N}$

elementary-number-theory divisibility

answered Oct 11, 2013 at 14:07

14 votes

Is there any conjecture that has been proved to be solvable/provable but whose direct solution/proof is not yet known?

answered Aug 12, 2018 at 22:27

9 votes

Accepted

Complete lattices and sublattices – which requirement is more stringent?

lattice-orders

answered May 16, 2011 at 0:28

8 votes

Showing that a set X with a trivial topology is not metrizable

general-topology metric-spaces

answered Apr 20, 2011 at 1:01

8 votes

Why is 'abuse of notation' tolerated?

soft-question notation

answered Dec 25, 2012 at 17:26

7 votes

Show: $\mathbb{C}=\overline{\mathbb{C}\setminus\left\{0\right\}}$

general-topology complex-analysis

answered Jul 17, 2013 at 14:38

7 votes

How to understand why $x^0 = 1$, where $x$ is any real number?

logarithms exponentiation exponential-function

answered Nov 15, 2012 at 23:25

7 votes

Is the box topology good for anything?

general-topology product-space box-topology

answered May 5, 2011 at 2:15

7 votes

Is there a Non-prime Number that is Divisible only by Numbers Greater than its Square Root?

prime-numbers

answered Jun 19, 2011 at 19:01

5 votes

Accepted

Does anyone know of any good ways to get good at algebra without as much"grind" as doing hundreds of questions a night

algebra-precalculus self-learning learning

answered May 15, 2011 at 1:04

5 votes

Accepted

If all the vectors of a basis of a vector space are contained in another space, is the first space a subspace of the second?

linear-algebra vector-spaces

answered Oct 18, 2011 at 22:39

5 votes

How it is posible that $\omega$-inconsistency does not lead to inconsistency

logic formal-systems incompleteness

answered Feb 18, 2012 at 13:59

5 votes

Example of a conjecture/theorem which required an entirely new idea to prove

soft-question

answered Dec 16, 2012 at 22:48

5 votes

Accepted

What underlies formal logic (or math, generally)?

logic soft-question formal-languages philosophy foundations

answered Dec 18, 2013 at 14:18

5 votes

Is Scrabble's method of determining turn order fair?

probability recreational-mathematics

answered Aug 29, 2017 at 17:05

5 votes

Possibility of getting odd pair socks

probability

answered Jun 25, 2011 at 11:58

4 votes

Accepted

Subset Relation: Is the subset relation a partial order?

relations

answered Oct 6, 2014 at 15:05

4 votes

Accepted

Theorems which are proven by proving the existence of a formal proof without knowing the formal proof

logic soft-question

answered Apr 29, 2014 at 22:36

4 votes

Direct proof set theory.

elementary-set-theory logic

answered Sep 19, 2013 at 23:13

4 votes

Concept of set without concept of member?

set-theory

answered Aug 13, 2013 at 0:51

4 votes

Accepted

Why are convex sets assumed / defined to be subsets of vector spaces (and not of more general spaces)?

soft-question convex-analysis

answered Oct 5, 2011 at 23:16

4 votes

Accepted

Books and Papers that have treatment of properties like Idempotence and related operations

abstract-algebra reference-request relations

answered Apr 22, 2011 at 22:48

4 votes

Bad Fraction Reduction That Actually Works

elementary-number-theory arithmetic fractions fake-proofs

answered Jul 6, 2011 at 1:36

3 votes

Two posets and a function

order-theory

answered Jul 7, 2011 at 20:57

3 votes

Upper limit of summation index lower than lower limit?

sequences-and-series

answered Apr 25, 2011 at 21:14

3 votes

Generate the smallest $\sigma$-algebra containing a given family of sets

measure-theory

answered Oct 11, 2012 at 19:47

3 votes

Accepted

If G is a finite group and $x \in G$, there is an integer n $\geq 1$ such that $x^n = e$

abstract-algebra group-theory finite-groups

answered Apr 17, 2014 at 23:28

3 votes

Is the set of proposition symbols necessarily a countable set?

logic propositional-calculus

answered Dec 11, 2018 at 13:14

3 votes

Accepted

Can you make a Sine wave with a straight edge and compass?

geometry geometric-construction

answered Oct 9, 2021 at 18:56

2 votes

Accepted

POSET as a disjoint union of a well ordered set and a set with no least element

relations

answered Sep 15, 2021 at 13:39

Stack Exchange Network

current community

your communities

more stack exchange communities

121 Answers

How can I prove that one of $n$, $n+2$, and $n+4$ must be divisible by three, for any $n\in\mathbb{N}$

Is there any conjecture that has been proved to be solvable/provable but whose direct solution/proof is not yet known?

Complete lattices and sublattices – which requirement is more stringent?

Showing that a set X with a trivial topology is not metrizable

Why is 'abuse of notation' tolerated?

Show: $\mathbb{C}=\overline{\mathbb{C}\setminus\left\{0\right\}}$

How to understand why $x^0 = 1$, where $x$ is any real number?

Is the box topology good for anything?

Is there a Non-prime Number that is Divisible only by Numbers Greater than its Square Root?

Does anyone know of any good ways to get good at algebra without as much"grind" as doing hundreds of questions a night

If all the vectors of a basis of a vector space are contained in another space, is the first space a subspace of the second?

How it is posible that $\omega$-inconsistency does not lead to inconsistency

Example of a conjecture/theorem which required an entirely new idea to prove

What underlies formal logic (or math, generally)?

Is Scrabble's method of determining turn order fair?

Possibility of getting odd pair socks

Subset Relation: Is the subset relation a partial order?

Theorems which are proven by proving the existence of a formal proof without knowing the formal proof

Direct proof set theory.

Concept of set without concept of member?

Why are convex sets assumed / defined to be subsets of vector spaces (and not of more general spaces)?

Books and Papers that have treatment of properties like Idempotence and related operations

Bad Fraction Reduction That Actually Works

Two posets and a function

Upper limit of summation index lower than lower limit?

Generate the smallest $\sigma$-algebra containing a given family of sets

If G is a finite group and $x \in G$, there is an integer n $\geq 1$ such that $x^n = e$

Is the set of proposition symbols necessarily a countable set?

Can you make a Sine wave with a straight edge and compass?

POSET as a disjoint union of a well ordered set and a set with no least element