Skip to main content

Explore our questions

2 votes
3 answers
149 views

Proving an heuristic bound involving the gaussian

6 votes
2 answers
59 views

Cubic equation for closest point to a function

12 votes
3 answers
589 views

Die dilemma: get paid the sum or go home

1 vote
2 answers
44 views

About the relationship between flatness as $R$-module of an ideal $K$ of a commutative ring $R$ and the flatness of the quotient $R/K$

0 votes
0 answers
5 views

Understanding Achim Klenke's Probability Theory, Proof of Theorem 15.34

2 votes
1 answer
746 views

Unfair Coin Toss

1 vote
0 answers
12 views

How to recover an affine group scheme

6 votes
2 answers
100 views

Connected components on a regular manifold

1 vote
1 answer
29 views

What is the shortest way to write an equivalent relation between n number of elements assuming that the transitive property is invalid.

2 votes
0 answers
62 views
+300

Specific invariants for cyclic groups in Galois theory

3 votes
1 answer
750 views

Hartman-Grobman Theorem - Necessary?

7 votes
3 answers
804 views

Where do hash functions come from?

3 votes
1 answer
773 views

"Functional example" of Cauchy sequence which is not convergent

1 vote
0 answers
95 views

Some examples of distributions of real random variables ( Achim Klenke, Probability Theory )

21 votes
3 answers
395 views

Does $\sum_{n=0}^{\infty}\frac{(4n)!^2}{2^{8n}(n+1)^2(2n)!^4}$ has the proposed closed form?

2 votes
1 answer
29 views

How to find Farkas certificates?

5 votes
1 answer
47 views

Does every Moore closure operator that satisfies $cl(\emptyset)=\emptyset$ arise as an intersection of Kuratowski closure operators?

0 votes
0 answers
32 views

Number of Solutions to $x^2 - y^2 \equiv n \pmod {m} $

44 votes
4 answers
42k views

Name for diagonals of a matrix

0 votes
1 answer
77 views

Trivial base change theorem in a Grothendieck site

1 vote
1 answer
752 views

Proof that for any n-sided polygon P, and any integer m greater than n, there is an m-sided polygon with the same area and perimeter as P?

1 vote
0 answers
70 views

Does anything deeper hide behind this inequality?

4 votes
3 answers
205 views

Formula for cycloid?

3 votes
1 answer
143 views

The name of an algebraic structure satisfying $y*(y*x)=x=(x*y)*y$

5 votes
0 answers
110 views

How many points are needed to cover a whole lattice?

22 votes
2 answers
3k views

Why are normal subgroups called "normal"?

6 votes
4 answers
9k views

What is the meaning of "independent events " and how can we logically conclude independence of two events in probability?

2 votes
1 answer
28 views

Proving $A = B$ under positive eigenvalue condition and equation $A^4 + 2A^3B = 2AB^3 + B^4$, without assuming commutativity

4 votes
0 answers
88 views
+250

Over $\mathbb R^2$, given a tool that can $n$-sect an angle for any $n$, for which $n$ can you construct the $n$th root of any given $x > 0$?

0 votes
1 answer
48 views

Average distance between all the points on 3d surface

0 votes
0 answers
21 views

Recommend a book on elliptic curves that can be used to learn cryptography?

2 votes
3 answers
139 views

Recommended books in Quantum Field Theory for students major in mathematics

0 votes
0 answers
11 views

Obtaining One of Multiple Subsets Coupon Collector Variant

6 votes
1 answer
231 views

Find minimum of $\sum\limits_{i=1}^{n}a^2_{i}-2\sum\limits_{\mathrm{cyc}} a_1 a_2$ subject to $\sum\limits_{i=1}^n a_i = 1$

1 vote
1 answer
55 views

Possible game states of card game Naishi

0 votes
1 answer
29 views

Collinearity of $M', H, N'$ where $M', N'$ are reflections of midpoints across sides of the intouch triangle

4 votes
0 answers
62 views

The role of the de Rham theorem in $\nabla C^\infty(X)\cong C^\infty_0(X)$

2 votes
3 answers
338 views

Why are left and right cosets different in the non-normal case?

1 vote
1 answer
179 views

Why does Fermat's little theorem not hold for all composite numbers?

1 vote
1 answer
138 views

A Collatz–type dynamical system with alternating multipliers ($3$ and $5$): three attractors and huge excursions

2 votes
1 answer
104 views

Showing that a ring is Cohen-Macaulay

1 vote
0 answers
131 views

Replace a random variable by a "small" Gaussian

11 votes
10 answers
775 views
+200

Seeking different ways you can find $x=8$ in $(x-6)^3 = x^{\frac{1}{3}}+6$

0 votes
1 answer
931 views

Find the growth rate for $y=4^{x +1}$

5 votes
1 answer
385 views

Compute $\sum_{k=1}^3\Big(\sum_{r=1}^\infty\Big(\frac{\tan\frac\theta{2^r}}{2^r}\Big)^k\Big)+\sum_{r=1}^\infty\frac{\tan\frac\theta{2^r}}{8^r}$

32 votes
6 answers
7k views

How to evaluate $\int_{0}^{2\pi}e^{\cos \theta}\cos( \sin \theta) d\theta$?

0 votes
0 answers
15 views

Proof of a continuous map $h:S^1 \to X$ is nullhomotopic iff $h_*$ is trivial homomorphism without lifting

2 votes
1 answer
61 views

Are there infinitely many odd composite numbers with digit-disjoint factorizations?

0 votes
0 answers
10 views

Caro Wei bound with second neighbors in triangle free graphs

4 votes
3 answers
391 views

Prove or disprove $\sum\limits_{\mathrm{cyc}} \sqrt{a_1a_2} \ge \sum\limits_{\mathrm{cyc}} \sqrt[3]{a_1a_2a_3}$ for $0 \le a_1 \le \cdots \le a_n$

39 votes
1 answer
3k views

Is War necessarily finite?

2 votes
1 answer
765 views

Russian problem book on Real Analysis, Functional Analysis, Topology, et al.

5 votes
2 answers
661 views

Name of the algebraic structure

0 votes
1 answer
34 views

Showing positive definite quadratic forms give the "most symmetrical" metrics over $\mathbb{R}^n$

2 votes
0 answers
107 views

Self-adjoint operators with empty essential spectrum have compact resolvent

3 votes
1 answer
928 views

Unique factorization fails in cyclotomic integers for $p=23$

7 votes
5 answers
730 views

Canonicity of the push-pull map for sheaves of sets

0 votes
1 answer
26 views

On the dimension of a linear system to give an embedding in $\mathbb{P}^3$

0 votes
1 answer
921 views

Prove that if $f$ is Riemann integrable on $[0,1]$, then $f$ is measurable and it equals to Lebesgue integral.

0 votes
1 answer
51 views

Structure Theorem for finitely generated modules over PID Proof

3 votes
0 answers
30 views

Computing the Positive Real Zero of the Symbolic Antiderivative of the Riemann-Zeta Function

2 votes
1 answer
2k views

How to find the conditional density of $X$ given an event $A$ has happened?

10 votes
0 answers
281 views

Why is the Whitehead product $[\iota_2, \eta] : \pi_4\mathbb{S}^2$ trivial?

0 votes
2 answers
778 views

How would I find the Context Free Grammar for the complement of $L = \{a^n \mid n\geq 0\}$? The alphabet is $\{a\}$.

0 votes
0 answers
27 views

Estimates in Hahn decomposition for measures of finite positive variation

3 votes
4 answers
4k views

How to change the sign of the Dirac delta function argument?

1 vote
1 answer
18 views

Characterization of the $\sigma$-ideal generated by wandering sets for a measureable system $(X,\mathcal{B},T)$

3 votes
1 answer
71 views

Is this set of Diophantine equations independent?

-2 votes
0 answers
40 views

$\sum_{j=2}^{k+1} \sum_{p=k+1}^\infty \frac{1}{p j^p} + \sum_{j=k+2}^\infty \sum_{p=2}^\infty \frac{1}{p j^p}<\frac{1}{k+1}$ for all $k \ge 2$.

0 votes
1 answer
83 views

I'm struggling with a logic problem and need some help understanding my mistake

5 votes
1 answer
301 views

Which theorems and definitions do I need to know to prove the impossible chessboard puzzle has a solution for every number of squares?

2 votes
0 answers
46 views

Contractibility of topological embeddings

-1 votes
0 answers
23 views

CW-structure on $ X = S^1\times\partial D^2 \;\cup\; \{x,y\}\times D^2 \subset T=S^1\times D^2. $

1 vote
1 answer
57 views

In how many ways a mouse can get in the $j$-th cell in the $i$-th row?

2 votes
2 answers
117 views

Simplest Fraction in Interval

11 votes
8 answers
2k views

Finding $ \int^1_0 \frac{\ln(1+x)}{x}dx$

0 votes
1 answer
29 views

Equivalences of a generator module

1 vote
1 answer
749 views

One sided limit of composite function

3 votes
1 answer
58 views

Prove that the sum of concatenation of all nonzero single digits (except $0$ in base 1) in first $2026$ bases is not a square

0 votes
0 answers
20 views

Reference for classical action of the standard height function on the two-torus written as sum of elementary and elliptic integrals?

6 votes
1 answer
258 views

Why Bohr's definition of almost periodicity?

3 votes
0 answers
51 views

For which $n$ and $k$ does there exist a "cursed" centrifuge arrangement?

1 vote
0 answers
29 views

Find the maximum of the following function $Q(x_1, x_2, ..., x_N)$ subject to some constraints.

0 votes
0 answers
37 views

Confusion regarding Tangent Basis

17 votes
2 answers
513 views

Help with $\int_{0}^{\pi /4} x^3 (\sqrt{\tan (x)} + \sqrt{\cot (x)}) dx$

133 votes
29 answers
26k views

Different ways to prove there are infinitely many primes?

12 votes
1 answer
386 views

Convergence of Laplace transform

3 votes
1 answer
110 views

The number of strings with bounded partial sums

1 vote
0 answers
35 views

Determining the location of portals using air pressure

0 votes
0 answers
33 views

Lie groupoid equivalence implies homotopy equivalence of classifying spaces

3 votes
1 answer
143 views

$=$-sign within factorial: is this an ancient notation for the Pochhammer symbol or just a typo?

2 votes
3 answers
329 views

Closed form for $\int_{0}^{1} \frac{\tan^{-1} x}{1+x+x^2}dx$

0 votes
1 answer
768 views

Tangent Space Projector from Riemannian Metric

0 votes
0 answers
14 views

Properties of self-concordant functions

3 votes
7 answers
408 views

Proof that limit points are unique

16 votes
2 answers
1k views

The (alternating) sum of reciprocals of ${n\choose 0}, {n\choose 1}, ... {n\choose n}$

Browse more Questions