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Interesting 21 Bountied Hot Week Month
0 votes
1 answer
13 views

Extreme bias in MLE for an exponential distribution sampled over a finite window.

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JimB
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-1 votes
1 answer
133 views

Can the usual English wording of two equivalent formulas fail to be equivalent?

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ryang
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9 votes
2 answers
518 views

A negation producing mathematical nonsense?

ryang's user avatar
ryang
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1 vote
1 answer
739 views

Using the method of characteristics to find a general solution to PDE

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5 votes
2 answers
112 views

Remote generation of functions

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flippiefanus
  • 226
0 votes
1 answer
73 views

Solve the equation $a^{\,\log_{2b}\!\left(x+\frac{b}{x}\right)} = \frac{(a+2b)x - b^{2} - x^{2}}{x}, $

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Claude Leibovici
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13 votes
4 answers
11k views

When is $2$ a quadratic residue mod $p$?

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19021605
  • 1,305
0 votes
0 answers
9 views

If $k\vec{a}+m\vec{b}+n\vec{c}=2\vec{a}+3\vec{b}+4\vec{c}$

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Angelo Mark
  • 6,350
2 votes
1 answer
64 views

Looking for the next term(s) in a sequence

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Tomita
  • 3,334
3 votes
0 answers
155 views

Is it true that $4n+1 \nmid F_n+7$?

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John
  • 173
0 votes
1 answer
41 views

Dual space of Frechet spaces

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user760
  • 3,012
2 votes
1 answer
43 views

Problem about cyclotomic polynomials and the order of an element modulo p

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匚ㄖㄥᗪ乇ᗪ
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4 votes
0 answers
21 views

similarity implies unitarily equivalent in C*-algebra

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David Gao
  • 25.8k
1 vote
1 answer
754 views

AR(2) process covariance stationarity - what am I doing wrong?

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5 votes
2 answers
138 views
+50

Minimum cardinality of the set of values for a sequence($a_1,a_2...a_{2025}$) with distinct cyclic ratios

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thedeepdeepsky
  • 745
0 votes
1 answer
20 views

Estimate in Bollobás "Modern Graph Theory"

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Vezen BU
  • 2,340
1 vote
1 answer
60 views

On evaluating an integral and the use of residue theorem.

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naturallyInconsistent
  • 691
0 votes
1 answer
88 views

About the definition of the limit of functions in $\mathbb R$

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krm2233
  • 8,149
0 votes
1 answer
35 views

Rudin Principles - Exercise 7.10 Functional series M test

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spaceisdarkgreen
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3 votes
2 answers
635 views

Proving total boundedness of a subset of a metric space

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skip
  • 1
0 votes
0 answers
16 views

Continuous and Discrete Variables

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theunknownZ
  • 1
0 votes
1 answer
166 views

Show that $p_{3n} \nmid n^2+1$

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Bhaskar Vashishth
  • 11.9k
0 votes
1 answer
745 views

Expected value of sum of elements of a subset of $\{1,..n\}$

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CommunityBot
  • 1
4 votes
2 answers
185 views

Probability that 1 is a double root of a random degree-5 integer polynomial with bounded nonzero coefficients

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mezzoctane
  • 1,946
16 votes
12 answers
905 views

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

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Игорь
  • 303
24 votes
4 answers
993 views

Six circles in a rectangle: show that two lengths are equal

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Dan
  • 40.6k
1 vote
1 answer
40 views

Karatzas Shreve Problem 1.3.9

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spaceisdarkgreen
  • 69.9k
4 votes
1 answer
74 views

Contractibility of topological embeddings

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Moishe Kohan
  • 114k
44 votes
5 answers
4k views

Is this 1-line proof of Cayley–Hamilton incomplete?

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krm2233
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12 votes
3 answers
533 views

Formula for the number of divisors of an integer

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Bill Dubuque
  • 285k
-1 votes
1 answer
77 views

Almost Harmonic Mean Inquality

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Bill Dubuque
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4 votes
3 answers
3k views

how to construct 17-vertexed graph for Ramsey number R(3,6)=18

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Oscar Lanzi
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0 votes
1 answer
761 views

For what values of $x$ in $[0,2π]$ does the graph of $y=\cos{x}/(\sqrt{3}+\sin{x})$ have a horizontal tangent?

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1 vote
2 answers
56 views

Given $8$ lines on a plane and no two of them are parallel. Prove that, at least two of them form an angle less than $23^{\circ}$

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Henry
  • 173k
2 votes
2 answers
106 views

Does $4x^4+48x^3y+188x^2y^2+296xy^3+161y^4=z^2$ have integer solutions other than $(x,y)=(19t,23t)$?

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Tomita
  • 3,334
5 votes
1 answer
107 views

Find the solution of $ \sigma(n)=\sigma(n-1)+d(n) $.

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Ataulfo
  • 33.7k
0 votes
1 answer
745 views

Line bundle $L$ on the complex torus $T$

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1 vote
2 answers
1k views

Connection form and dual $1$-forms for frame field on $\Bbb{R}^2$ defined in terms of angles

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Ted Shifrin
  • 128k
6 votes
2 answers
1k views

How does the Hopf map generate $\pi_3(S^2)$?

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John Hughes
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2 votes
2 answers
783 views

surface of sphere $x^2+y^2+z^2=25$ below the plane $z=4$

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user170231
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2 votes
1 answer
153 views

Prove $\frac{4}{a^2 + 2b^2 + 3c^2 + 10} \le \frac{5a + 3b + c + 7d}{16(a+b+c+d)}$ for positive reals $abcd=1$

River Li's user avatar
River Li
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5 votes
1 answer
65 views

When is the union of two disjoint zero-dimensional subspaces a zero-dimensional subspace?

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Alessandro Codenotti
  • 13k
1 vote
0 answers
42 views

Prove $\sum\limits_{\mathrm{cyc}}\log_a(a^2+b^2+c^2) \le \sum\limits_{\mathrm{cyc}} a\log_a(abc)$ for $a+b+c=1$

River Li's user avatar
River Li
  • 51.4k
9 votes
11 answers
735 views

Is there a "natural" example of a poset that is not a lattice?

Arthur's user avatar
Arthur
  • 206k
2 votes
1 answer
49 views

Is there a simple proof of this metric relation in this Sangaku?

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Pompombojam
  • 101
3 votes
1 answer
58 views

Proof of dividing a square into six equal parts

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Anand
  • 3,814
0 votes
1 answer
748 views

Constructibility of Regular $N$-gon $\implies$ Constructibility of Regular $2N$-gon

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4 votes
1 answer
385 views

Prove that $\sum\limits_{\mathrm{cyc}} (a^{60}c^{10} + a^{50}c^{20} - 2a^{51}b^9c^{10}) \ge 0$

River Li's user avatar
River Li
  • 51.4k
6 votes
3 answers
301 views
+200

A problem about permutation group to find the minimum cardinality of a set

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Alex Ravsky
  • 108k
2 votes
1 answer
236 views
+50

Replace a random variable by a "small" Gaussian

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BGM
  • 7,879
11 votes
1 answer
548 views

How to compute $\int_0^1\frac{\ln x}{x^2-x-1}dx$ without using polylogarithmic function $\text{Li}_2(z)$

Quanto's user avatar
Quanto
  • 125k
1 vote
3 answers
802 views

How to evaluate $ \sum_{n=1}^\infty \frac{H_n^{(2)}}{n^3}$

FDP's user avatar
FDP
  • 16.2k
2 votes
0 answers
30 views

Explicit description of map from étale cohomology to the Brauer group

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J. Grube
  • 116
2 votes
3 answers
2k views

Proving $\sup \left( {A + B} \right) = \sup A + \sup B$ using the usual definition.

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Anne Bauval
  • 51.3k
0 votes
1 answer
45 views

Rational points on Noetherian $k$-algebras?

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KReiser
  • 76.4k
4 votes
1 answer
117 views

Question on a proof by Spivak

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Steppenwolf
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1 vote
0 answers
113 views

Is a the sign of the Lyapunov exponent a sufficient condition for chaos?

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Gonçalo
  • 16.6k
2 votes
1 answer
1k views

Fundamental group of the sphere via triangulation

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CommunityBot
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3 votes
1 answer
150 views
+50

Graphing the rational function $f(x)=\frac{3x}{x^2+x-2}$

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rogerl
  • 22.9k
2 votes
1 answer
146 views
+100

On solving the nested functional equation $f(f(x) + 2020x + y) = f(2021x) + f(y)$

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Marco
  • 4,155
2 votes
2 answers
97 views
+50

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

timon92's user avatar
timon92
  • 12.4k
0 votes
1 answer
64 views

Prove that $|1 - z| \ge \frac{2}{n-1}$.

Letac Gérard's user avatar
Letac Gérard
  • 4,108
6 votes
2 answers
118 views

Equation of circle after affine transformation

Hosam Hajeer's user avatar
Hosam Hajeer
  • 298
5 votes
1 answer
769 views

Fundamental solution of Poisson equation on the torus

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Dan Asimov
  • 1,197
8 votes
1 answer
266 views

Asymptotic expansion as $x \rightarrow \infty$ of $\sum_{n \le x} \lfloor\frac{x}{n}\rfloor \left\{{2\sqrt{\lfloor\frac{x}{n}\rfloor}}\right\}$

Lorenz H Menke's user avatar
Lorenz H Menke
  • 1,097
3 votes
2 answers
63 views

Find Angle in Isosceles Triangle with Constructions Involving Circumcenter and Reflections

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sirous
  • 13.8k
2 votes
1 answer
2k views

Proof of $\sup C =\sup A +\sup B$

Anne Bauval's user avatar
Anne Bauval
  • 51.3k
2 votes
1 answer
28 views

the cardinality of the set of removable/jump discontinuity points

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Dermot Craddock
  • 5,589
2 votes
2 answers
73 views

Intuition behind $\oint_{|z|=1} \frac{1}{z-a}\,dz$ depend only on whether $a$ is inside the circle.

J.G.'s user avatar
J.G.
  • 119k
1 vote
2 answers
339 views

Differential Geometry - Inverse is continuous

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Ilay Wischevsky Shlush
  • 1
0 votes
1 answer
33 views

Reference request for $\dim_K(P^m(u))=m\deg(P)$

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blargoner
  • 3,516
22 votes
0 answers
428 views

A sequence based on arithmetic derivative that always converges to prime numbers

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Augusto Santi
  • 3,182
0 votes
0 answers
27 views

Homeomorphism between n-simplex and n-disk

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YourTypicalMathEnjoyer
  • 21
1 vote
1 answer
1k views

Product of a concave function and a decreasing function

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CommunityBot
  • 1
2 votes
1 answer
84 views

Approximating rectifiable Jordan curves from within

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David Herron
  • 31
2 votes
1 answer
8k views

Supremum of set of sum of elements

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Anne Bauval
  • 51.3k
0 votes
0 answers
9 views

How should one view $\Delta \in PI(\mathcal I)$ in the context of outer space $CV_r$?

J. Zimmerman's user avatar
J. Zimmerman
  • 1,262
0 votes
0 answers
37 views

Is the layer-cake representation really an equivalent definition of the Lebesgue integral without $\sigma$-finiteness?

Markus Klyver's user avatar
Markus Klyver
  • 2,638
3 votes
2 answers
512 views

Please check my proof that $\sup(A) + \sup(B)$ is the least upper bound of $A+B$.

Anne Bauval's user avatar
Anne Bauval
  • 51.3k
2 votes
0 answers
108 views

What amount of category theory can we rigorously do only assuming ZFC axioms?

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Kristaps John Balodis
  • 1,506
0 votes
0 answers
15 views

Why do we supposed to use Log function in Logistic regression's cost calculation.

Sivaraj C's user avatar
Sivaraj C
  • 1
-1 votes
0 answers
20 views

Berry-Esseen bound for U-statistics

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CantorEuler1996
  • 137
4 votes
1 answer
176 views

Ranges achievable by rational functions of two variables

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hbghlyj
  • 6,343
0 votes
0 answers
7 views

self adjoint element in an abelian von Neumann subalgebra

mathbeginner's user avatar
mathbeginner
  • 1,995
2 votes
1 answer
84 views

How to find Farkas certificates?

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Siong Thye Goh
  • 155k
1 vote
0 answers
44 views

Number of Dyck paths avoiding DUDUDD and not ending with DUDUD

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JustAsking
  • 317
1 vote
0 answers
29 views

Prerequisites for Beilinson-Bernstein

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marcus1518
  • 147
-1 votes
1 answer
68 views

Another result for the Ramanujan summation

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LLMATHS
  • 1
5 votes
0 answers
66 views

Is a smooth convex curve a conic if the midpoints of parallel chords always lie on a line?

hbghlyj's user avatar
hbghlyj
  • 6,343
3 votes
4 answers
815 views

What is the rigorous definition of the ratio of two numbers?

ryang's user avatar
ryang
  • 45.4k
0 votes
0 answers
29 views

Regular homotopy confusion

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Gilad Derfner
  • 130
0 votes
0 answers
76 views
+100

Can we formally define generalised formal theories just like we can define generalised Turing machines?

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Ryder Rude
  • 1,587
2 votes
2 answers
203 views

Suppose that the function $f$ maps every compact set to a compact set. If the preimage of every point is a closed set, then $f$ is continuous.

Dean Miller's user avatar
Dean Miller
  • 9,401
1 vote
1 answer
290 views

Closed form for summation: $\sum\limits_{c_0+c_1+\cdots+c_n = n \atop c_n = n-i}\prod\limits_{j=0}^n{j \choose c_j}$

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DroneBetter
  • 809
0 votes
2 answers
112 views

How to find $L=\prod\limits_{n\ge1}\frac{(\pi/2)\arctan(n) }{\arctan(2n) \arctan(2n-1) }$?

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Claude Leibovici
  • 298k
0 votes
2 answers
59 views

A non valid triangulation on the torus

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Lee Mosher
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