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Popular Question

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When does a generating set for a free module contain a basis?

Awarded Nov 27 at 22:05

William Sun

2,60310 silver badges21 bronze badges

Mapping torus for $\sigma:\; S^1 \longrightarrow S^1$ as a pushout of $S^1 \subset D^2$ and some $\varphi:\; S^1 \rightarrow S^1 \vee S^1$

Awarded Nov 27 at 20:12

polynomial_donut

1,1287 silver badges21 bronze badges

Second Variation of Area Functional

Awarded Nov 27 at 19:43

Ivo Terek

80.8k15 gold badges113 silver badges248 bronze badges

Find the largest subset of $S=\{1,2,3,....,20\}$ such that its no two elements differ by $4$ or $7$.

Awarded Nov 27 at 18:11

Vasu Gupta

1,0804 silver badges14 bronze badges

For every finitely generated ideal $I\subset A$ the map $I\otimes_A M\rightarrow A\otimes_A M$ is injective, then $M$ is flat.

Awarded Nov 27 at 18:02

njlieta

4815 silver badges25 bronze badges

Have symmetric matrices for which the $(i,j)$ entry is $\min(i,j)$ earned a name?

Awarded Nov 27 at 18:02

Rodrigo de Azevedo

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Clarification on "polynomial over a field"

Awarded Nov 27 at 17:46

user8989

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Representation of Transcendental number via continued fractions

Awarded Nov 27 at 17:36

kolobokish

7524 silver badges15 bronze badges

Are matrices best understood as linear maps?

Awarded Nov 27 at 17:16

Jack M

28.7k7 gold badges71 silver badges137 bronze badges

Finding $\lim_{n\to\infty}\int_0^{\frac{1}{2^n}}(1+\cos(x))^n\,dx$

Awarded Nov 27 at 17:10

Yup8

777 bronze badges

Find the real and imaginary parts of $f(z)=\frac{2}{z+1}$

Awarded Nov 27 at 16:47

chris

6712 gold badges6 silver badges11 bronze badges

Determining whether a lattice is complemented

Awarded Nov 27 at 15:50

Damian Jacobs

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Pullback commutes with lie derivative?

Awarded Nov 27 at 14:57

user1234567890

4302 silver badges12 bronze badges

Basis of a vector space and subspace

Awarded Nov 27 at 14:51

Mathmanskip

675 bronze badges

The definition of a rational representation of a linear algebraic group

Awarded Nov 27 at 14:43

stupid_question_bot

1,2537 silver badges9 bronze badges

Conditions for solvability of Poisson's equation with Neumann boundary condition

Awarded Nov 27 at 14:36

qoat

412 bronze badges

Why Fourier transform is tempered distribution?

Awarded Nov 27 at 14:36

Creator

3,2282 gold badges23 silver badges42 bronze badges

Ergodicity of the First Return Map

Awarded Nov 27 at 13:45

user35682

4843 silver badges10 bronze badges

Expected number of cycles in random function

Awarded Nov 27 at 13:45

2080

2013 silver badges15 bronze badges

Explanation of continued fraction for Bessel functions

Awarded Nov 27 at 13:02

Alex Meiburg

2,57112 silver badges24 bronze badges

Distribution of $X\sqrt {2Y}$ where $X\sim N (0,1)$ and $Y\sim \operatorname{Exp} (1)$

Awarded Nov 27 at 13:02

JustANoob

1,73912 silver badges26 bronze badges

Academic reference concerning Minkowski's question mark function

Awarded Nov 27 at 12:41

Casper

1,0446 silver badges20 bronze badges

The Fredholm index is locally constant

Awarded Nov 27 at 11:50

pomegranate

7533 silver badges11 bronze badges

Potential error in the paper: "Every positive integer is the sum of three palindromes"

Awarded Nov 27 at 11:41

TheOutZ

1,48911 silver badges23 bronze badges

Prove that every terms of a sequence defined by a recurrence relation is a perfect square.

Awarded Nov 27 at 11:34

user488002

914 bronze badges

Prove: $\int_{-1}^1 x^n P_n(x) dx = \frac{2^{n+1}n!^2}{(2n+1)!}$

Awarded Nov 27 at 11:05

Carlos Eduardo Staudt

1196 bronze badges

Book recommendation for masters student with no maths background

Awarded Nov 27 at 10:23

naz

3,5195 gold badges26 silver badges58 bronze badges

Can a linear function have zero slope?

Awarded Nov 27 at 9:47

Reza Hosseinzadeh

234 bronze badges

Can someone confirm my method and answer for this trig problem?

Awarded Nov 27 at 7:51

Sarah Rubenstein

2452 silver badges6 bronze badges

How to find the range and kernel of a linear transformation T(x1, x2, x3, x4...) = (x1, x3, x5, x7...)?

Awarded Nov 27 at 7:30

agviao12

435 bronze badges

If two random variables have CDFs that have the same value for all x, can we assume the random variables are equal?

Awarded Nov 27 at 7:19

Joseph Garvin

1,26012 silver badges26 bronze badges

Combinatorics problem; counting in two ways, china 1993

Awarded Nov 27 at 6:42

shahin nematy

494 bronze badges

Covering chessboard with L-tetrominoes

Awarded Nov 27 at 6:28

Jebediah

5433 silver badges18 bronze badges

A combinatorial card problem

Awarded Nov 27 at 5:58

ncmathsadist

50.3k3 gold badges86 silver badges135 bronze badges

What is $\lim_{x \rightarrow 0} x^0$?

Awarded Nov 27 at 5:40

limito

533 bronze badges

Largest subset with no pair summing to power of two

Awarded Nov 27 at 5:40

Dexter

2,00310 silver badges27 bronze badges

Colouring the sides of a hexagon

Awarded Nov 27 at 5:32

Esther Rose

1477 bronze badges

2013 Putnam A1 Proof understanding (geometry)

Awarded Nov 27 at 5:19

Lebes

1,7362 gold badges14 silver badges34 bronze badges

Find a Taylor Series and its radius of convergence for $f(x) = x^2.$

Awarded Nov 27 at 5:07

UH1

3491 gold badge5 silver badges11 bronze badges

Maximum possible number of colored cells in a 5x5 grid where no 3x3 subgrid can include more than 5 colored cells.

Awarded Nov 27 at 5:02

Kariya436869

235 bronze badges

Hilbert class field of $\mathbb Q(\sqrt{-14})$

Awarded Nov 27 at 4:49

Math123

1,27310 silver badges27 bronze badges

What is the relation among sides of triangle in oval (ellipse)

Awarded Nov 27 at 4:39

bolo

1497 bronze badges

A biquadratic equation to have at least two real roots

Awarded Nov 27 at 4:21

voreko9043

212 bronze badges

Doob's h-transform for Simple Random Walk

Awarded Nov 27 at 3:54

Simon

5773 silver badges14 bronze badges

What's maximum value of $x (1-x^2)$ for $0 < x <1$?

Awarded Nov 27 at 3:54

Physics freak

1797 bronze badges

Guess the right permutation game

Awarded Nov 27 at 3:48

malenkiy_scot

5172 silver badges11 bronze badges

How addition and multiplication works

Awarded Nov 27 at 3:31

user3243180

335 bronze badges

Prove that $f(x,y) =\frac{x^3-xy^2}{x^2+y^2}$ if $(x,y) \neq (0,0)$ and $f(0,0)=0$, is continuous in $\Bbb R^2$

Awarded Nov 27 at 3:26

BSplitter

1,75913 silver badges33 bronze badges

Generating Function explicit formula

Awarded Nov 27 at 1:42

Jono

335 bronze badges

finding code of a function in GAP packages [closed]

Awarded Nov 27 at 1:23

user146566

1158 bronze badges

Exercise from Serre's "Trees" - prove that a given group is trivial

Awarded Nov 27 at 1:08

Dennis Gulko

15.9k1 gold badge38 silver badges62 bronze badges

How to resolve Skolem's Paradox by realizing what can be said of a set is relative to what is in the domain of some model?

Awarded Nov 27 at 0:42

pichael

9096 silver badges14 bronze badges

Probability that a Mersenne number is prime

Awarded Nov 27 at 0:08

user188688

1817 bronze badges

Smallest size of set of real numbers such that the sum of any seven is strictly positive, and the sum of any eleven is strictly negative

Awarded Nov 27 at 0:08

Rich

412 bronze badges

Matrix-vector multiplication/cross product problem

Awarded Nov 26 at 21:33

Kurt Muster

453 bronze badges

Solve the system of equations for $\sqrt{xy}$

Awarded Nov 26 at 21:06

Lars Smith

7077 silver badges12 bronze badges

Convergent/divergent series $\sum_{n=2}^{\infty}(n\sqrt{n}-\sqrt{n^3-1})$

Awarded Nov 26 at 20:51

atomoutside

5131 gold badge5 silver badges13 bronze badges

Distribution of $1/(1+X^2)$ if $X$ is standard Cauchy

Awarded Nov 26 at 20:51

Luskentyrian

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Tensor Product Rules

Awarded Nov 26 at 20:51

murpw2011

3051 silver badge8 bronze badges

Relation between projection matrix and linear span

Awarded Nov 26 at 20:27

user568810

1219 bronze badges

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