User PseudoNeo

10 votes

Looking for (overkill) usages of indicator functions

answered 22 hours ago

2 votes

Prove/disprove that there are functions $f$ and $g$ that keep the condition, so that if $f$ is surjective and $g$ is injective.

answered Jun 11, 2022 at 21:08

0 votes

Accepted

Degree of minimal polynomial when number of distinct eigenvalues are given

answered Jan 30, 2021 at 22:43

6 votes

Accepted

Finding my mistake in a "proof" that there is no non-trivial knot

answered Jan 28, 2021 at 20:13

9 votes

Accepted

Intuitive reason of why the negation of $P \Rightarrow Q$ is $P \land \neg Q$ instead of $P \Rightarrow \neg Q$

answered Apr 21, 2020 at 19:46

4 votes

Accepted

Irreducible reps of $U(3,p)$

answered Jul 31, 2019 at 23:01

3 votes

Accepted

Finding the character table of this group

answered May 18, 2015 at 15:39

34 votes

Accepted

The set of functions which map convergent series to convergent series

answered Sep 29, 2014 at 15:00

33 votes

Accepted

Presentation $\langle x,y,z\mid xyx^{-1}y^{-2},yzy^{-1}z^{-2},zxz^{-1}x^{-2}\rangle$ of group equal to trivial group

answered Feb 6, 2015 at 8:27

1 vote

Dehn twist generators for mapping class group of a punctured disc

answered Jan 18, 2018 at 23:42

5 votes

Algebraic numbers expressible in terms of real-valued radicals

answered Jan 18, 2018 at 23:24

0 votes

Accepted

Can we recover the signature of a knot from an Alexander module presentation matrix?

answered Jan 18, 2018 at 22:55

0 votes

Very detailed book for topological K-theory

answered Nov 20, 2017 at 21:15

2 votes

Accepted

What was Poincaré's original idea of the fundamental group?

answered Nov 20, 2017 at 21:13

2 votes

Accepted

Restrictions on homology for compact orientable 3-manifolds

answered Jul 27, 2017 at 21:50

24 votes

What is the math behind the game Spot It?

answered May 4, 2011 at 8:36

0 votes

Prove that the quotient space $V/V^\perp$ is regular

answered Apr 7, 2017 at 10:17

1 vote

What is the order of the following elements in this group?

answered Oct 24, 2016 at 5:02

1 vote

Prove that $\sin^4\theta+\cos^4\theta=\frac{3+\cos4\theta}{4}$

answered Sep 21, 2016 at 20:04

2 votes

Is there any formula for $\sum_{k=1}^n k!$?

answered Aug 23, 2016 at 14:38

6 votes

Accepted

Can the long line be embedded in euclidean space?

answered Aug 16, 2016 at 12:38

0 votes

Are there functions of boolean parameters that must evaluate more than two variables?

answered Aug 10, 2016 at 19:05

2 votes

Divergence of sum of reciprocals of square-free numbers

answered Aug 1, 2016 at 8:39

5 votes

Accepted

Does the sum of reciprocals of this subset of the primes converge?

answered Jul 29, 2016 at 23:36

4 votes

Accepted

What algebra is generated by $\mathrm{O}(2)$?

answered Jul 25, 2016 at 9:59

1 vote

Linear independence of standard basis vectors from Vandermonde style vectors

answered Jul 22, 2016 at 15:11

7 votes

Why is $\mathrm{Spec}(\mathbb{Z})$ a terminal object in the category of affine schemes?

answered Jul 14, 2016 at 17:46

2 votes

Accepted

Real Projective $n$ space $\mathbb{R}P^{n}$

answered Jul 14, 2016 at 16:06

4 votes

Accepted

Notation for representing ANY number?

answered Jul 14, 2016 at 13:54

7 votes

Accepted

Can $x^2+y^2,y^2+z^2,z^2+x^2$ and $x^2+y^2+z^2$ all be square numbers?

answered Jul 14, 2016 at 13:11

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120 Answers

Looking for (overkill) usages of indicator functions

Prove/disprove that there are functions $f$ and $g$ that keep the condition, so that if $f$ is surjective and $g$ is injective.

Degree of minimal polynomial when number of distinct eigenvalues are given

Finding my mistake in a "proof" that there is no non-trivial knot

Intuitive reason of why the negation of $P \Rightarrow Q$ is $P \land \neg Q$ instead of $P \Rightarrow \neg Q$

Irreducible reps of $U(3,p)$

Finding the character table of this group

The set of functions which map convergent series to convergent series

Presentation $\langle x,y,z\mid xyx^{-1}y^{-2},yzy^{-1}z^{-2},zxz^{-1}x^{-2}\rangle$ of group equal to trivial group

Dehn twist generators for mapping class group of a punctured disc

Algebraic numbers expressible in terms of real-valued radicals

Can we recover the signature of a knot from an Alexander module presentation matrix?

Very detailed book for topological K-theory

What was Poincaré's original idea of the fundamental group?

Restrictions on homology for compact orientable 3-manifolds

What is the math behind the game Spot It?

Prove that the quotient space $V/V^\perp$ is regular

What is the order of the following elements in this group?

Prove that $\sin^4\theta+\cos^4\theta=\frac{3+\cos4\theta}{4}$

Is there any formula for $\sum_{k=1}^n k!$?

Can the long line be embedded in euclidean space?

Are there functions of boolean parameters that must evaluate more than two variables?

Divergence of sum of reciprocals of square-free numbers

Does the sum of reciprocals of this subset of the primes converge?

What algebra is generated by $\mathrm{O}(2)$?

Linear independence of standard basis vectors from Vandermonde style vectors

Why is $\mathrm{Spec}(\mathbb{Z})$ a terminal object in the category of affine schemes?

Real Projective $n$ space $\mathbb{R}P^{n}$

Notation for representing ANY number?

Can $x^2+y^2,y^2+z^2,z^2+x^2$ and $x^2+y^2+z^2$ all be square numbers?