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Interesting 15 Bountied Hot Week Month
6 votes
1 answer
976 views

"Hard" exercises on Linear Algebra and Analytic Geometry

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Dhairya Kumar
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1 vote
1 answer
61 views

Question on solving the equation $ z^2 - z - (5 - 5i) = 0$

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Dhairya Kumar
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0 votes
1 answer
120 views

Differential equation $yy'+2y=x$

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Gonçalo
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0 votes
0 answers
8 views

Does log-convexity of coefficients force a rigid differential hierarchy for power series?

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One day
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0 votes
0 answers
7 views

Clarification of a construction by Heinzer and Ohm of "An essential ring which is not a v-multiplication ring"

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rschwieb
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3 votes
1 answer
742 views

Solving multivariate polynomial to find closest point to a $3$ (or more) circles

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0 votes
1 answer
14 views

Elementary submodels of $L_{\omega_1}$.

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Noah Schweber
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0 votes
4 answers
12k views

If $60^a = 3$ and $60^b = 5$, then find $12^{\frac{1-a-b}{2(1-b)}}$

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Red Five
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0 votes
0 answers
156 views

Vojtěch Jarník 2026, P2

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Harish Chandra Rajpoot
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1 vote
1 answer
609 views

Linear transformation problem involving the intersection of the range and nullify of T

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14 votes
5 answers
4k views

Index of a maximal subgroup in a finite group

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Nicky Hekster
  • 53.4k
2 votes
1 answer
48 views

Understanding a step in differentiating $f(x)=\frac{x}{x-1}$ using the limit definition

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heropup
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4 votes
2 answers
1k views

About using Archimedean property to prove the existence of least upper bound

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1 vote
1 answer
115 views

Solving this coupled ODE system with sine

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Gonçalo
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1 vote
1 answer
136 views

The Probabilistic Method exercise 2.7.7

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3 votes
0 answers
148 views
+50

How to extend the following approximations of LogSumExp function into $N$ variables? (metrics defined in question)

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Joako
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0 votes
1 answer
614 views

Homothety and rotation and fixed point in complex analysis

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1 vote
1 answer
50 views

Integration by Parts Differential Changes

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heropup
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0 votes
1 answer
103 views

Are variable-exponent interpolation formulas for ellipse circumference known?

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Intelligenti pauca
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5 votes
5 answers
1k views

Why is $\sqrt [n] 1$ not an expression "in radicals" of a root of unity?

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Jianing Song
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14 votes
3 answers
492 views

Is the nearest miss $a^n + b^n + k_n = c^n$ of Fermat Last Theorem known for given n?

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Adam Bailey
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0 votes
1 answer
49 views

Interval of validity for initial value problem

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Gonçalo
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-2 votes
2 answers
97 views

Convergence of trigonometric sequences

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Anne Bauval
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1 vote
3 answers
2k views

Continuity of a Function with a Finite Domain

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user1752280priyangshupaul
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44 votes
3 answers
166k views

Proof for triangle inequality for vectors

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Peter Szilas
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6 votes
2 answers
181 views
+50

Why is the spin group needed to define the Dirac operator?

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Quaere Verum
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4 votes
0 answers
124 views

The maps $f$: $\mathbb{RP}^2$ $\to$ $\mathbb{RP}^2$ of degree $0$

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Sebastiano
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1 vote
1 answer
214 views

$A_1,A_2,...,A_k\subseteq \{1,2,...,11\}$ are such that for any three of them at least two are not comparable by inclusion. What is a maximum of $k$?

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bof
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0 votes
2 answers
52 views

Determine the dimensions of a cuboid from two perspective images of it and the distance between the two cameras positions

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sirous
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5 votes
0 answers
79 views
+200

What is the rigorous definition of a boundary layer?

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Leonidas
  • 1,138
4 votes
2 answers
61 views

A property of free cocompletions

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user43208
  • 9,573
2 votes
2 answers
176 views

A brief way to compute the residue of $f(z)=\frac{z^m}{(1-e^{-z})^{n+1}}$ at $z=0$?

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RobPratt
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0 votes
1 answer
616 views

Finding the solutions of nonlinear system with absolute value

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2 answers
73 views

Integration in the real domain $\int \frac{x^2}{(x^2+H)^2+F^2}~dx$

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Átila Correia
  • 20.5k
1 vote
1 answer
92 views

$4k+2$ unit cubes, each face-adjacent to 3 others.

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Mark Saving
  • 34.2k
4 votes
1 answer
122 views

Red–blue unit distance configuration with fixed degree

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Mark Saving
  • 34.2k
78 votes
9 answers
7k views

How can one prove that $e<\pi$?

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Robert Lee
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1 vote
0 answers
66 views

Almost fermat primes

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jjagmath
  • 25.5k
2 votes
1 answer
52 views

Coordinates of a vector not taken from the origin

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SV-97
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5 votes
0 answers
160 views

About the sum $\sum_{n=0}^{\infty}\frac{(4n)!}{2^{6n}(n+1)^3n!^2(2n)!}$

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2 votes
1 answer
899 views

A proof that the intersection of polytope and hyperplane is determined by the intersection of the hyperplane and polytope's edges?

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David Gao
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1 vote
1 answer
618 views

Derivation of transport equation

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Gonçalo
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3 votes
1 answer
179 views

Is the inversion density of the Collatz parity vector universally bounded below $\frac{1}{6}$?

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1 answer
41 views

Finding a density function of one variable based upon a density function of two variables

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heropup
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6 votes
3 answers
554 views

How to prove the parallelogram law from some axioms?

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Moe
  • 473
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1 answer
45 views

$N$ Players, $M$ Levels: Does Strategy Matter?

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Christophe Boilley
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2 votes
0 answers
40 views

Generalizing a geometric construction for the tribonacci constant to the tetranacci?

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Tito Piezas III
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6 votes
5 answers
4k views

Showing Bernstein polynomial is a basis

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s114
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1 vote
2 answers
2k views

Prove that $\operatorname{null} T_1 \subset \operatorname{null} T_2$ if and only if there exists $S \in L(W,W)$ such that $T_2 = ST_1$.

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Ben Steffan
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8 votes
8 answers
760 views

How do we know that the number $1$ is not equal to the number $-1$?

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Andrea Mori
  • 28.8k
-1 votes
3 answers
615 views

Finding the singular points and residues of a function --- help

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1 vote
1 answer
115 views

Parametric Solution to system of two quadratic equations

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Tito Piezas III
  • 62.8k
3 votes
1 answer
172 views

Combinatorics Problem Help (Vietnam Math Olympiad 2016 Day 1 Problem 4)

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Dominique
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2 votes
1 answer
618 views

If the orbit of a point $x$ is a closed set, then either $x$ has a periodic iterated or its omega-limit is empty.

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Alp Uzman
  • 12.6k
-1 votes
1 answer
623 views

What is the circuit rank of a complete graph?

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13 votes
2 answers
1k views

Given 20 distinct positive integers not greater than 99, prove or disprove that among their pairwise differences, at least four are equal ones.

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Misha Lavrov
  • 166k
0 votes
1 answer
180 views

Trigonometric indentity proof by induction: $\sin\alpha\sin2\alpha+\sin2\alpha\sin3\alpha+\ldots+\sin(n-2)\alpha\sin(n-1)\alpha=\frac{n}{2}\cos\alpha$

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Dhairya Kumar
  • 2,082
0 votes
1 answer
66 views

Probability of selecting group elements that sum to identity

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Shaun♦
  • 49.3k
1 vote
0 answers
62 views

Analysis 2 exercise, Integration into a Banach Space

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Hyraxlover
  • 55
7 votes
1 answer
649 views

Minimum expected number of 5-die rolls to simulate a fair 6-die

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1 vote
1 answer
66 views

How to demonstrate that $1_{\text{inf}_{n\ge k} A_n} = \inf_{n\ge k} 1_{A_n}$?

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knowledge today
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2 votes
3 answers
184 views

How to show that this octagon identification gives the double torus using group presentations?

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Lee Mosher
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0 votes
1 answer
641 views

Simple concrete example of a language that is Turing recognizable but not decidable

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River Li
  • 54.4k
-1 votes
1 answer
278 views

Smooth monotonically decreasing function to satisfy various constraints.

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River Li
  • 54.4k
1 vote
3 answers
266 views

$\chi(1)>1$, then $|\chi|^2$ is not an irreducible character.

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19021605
  • 1,712
3 votes
1 answer
58 views

Is the Poisson binomial test valid for a simple casino mines game?

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French Man
  • 3,143
1 vote
2 answers
351 views

How to express $ \int \sqrt{\frac{4 - \cos^2 x}{1 + 4 \cos x}} dx $ in terms of known functions?

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R. J. Mathar
  • 5,202
6 votes
3 answers
477 views

A beautiful heart-shaped curve generated from an ellipse and a circle

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Jean Marie
  • 93.4k
9 votes
3 answers
635 views

Is the topology that has the same sequential convergence with a metrizable topology equivalent as that topology?

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gaoqiang
  • 440
0 votes
1 answer
745 views

The velocity time graph of a particle moving along a straight line is shown in the following figure

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CommunityBot
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4 votes
2 answers
149 views

What is a PDiff or piecewise smooth manifold?

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Absurdus
  • 516
2 votes
2 answers
2k views

$a$ algebraic number, $\exists$ integer $n>0$ such that $na$ algebraic integer

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Daniel Aricatt
  • 150
2 votes
2 answers
111 views

Intersection of parametrizations of connected 1- manifolds and regularity

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mathuser1234
  • 43
1 vote
1 answer
87 views
+50

Unique reachability of a nonnegative configuration under local updates on a cycle

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mathlove
  • 158k
0 votes
1 answer
616 views

Interior of subset in product topology = product of each subset in own topology

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CommunityBot
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8 votes
1 answer
133 views

Riemann-sum approximation of the Itô integral: what are the minimal assumptions?

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Oğuzhan Kılıç
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2 votes
1 answer
611 views

Dual Simplex Method

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Rodrigo de Azevedo
  • 24.3k
3 votes
1 answer
239 views

Consistency between inner product, norms, and metrics

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River Li
  • 54.4k
10 votes
1 answer
629 views

Three sphere problem: What is the probability that the line segment intersects the plane?

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Dan
  • 43.7k
0 votes
0 answers
28 views

Plane Curve with No Cover by Connected Fixed-Radius Discs

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John Samples
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1 vote
2 answers
98 views

How to obtain real vector from abstract tangent vector in the case of the manifold $\mathbb R^n$

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Filippo
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5 votes
0 answers
71 views

Efficiently computing the subfields of $\mathbb{Q}(\sqrt[6]7, e^{\pi i / 3})$ via the Galois correspondence

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Robin
  • 7,054
8 votes
2 answers
12k views

Character Table S4

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19021605
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1 vote
1 answer
639 views

Solve $\min\limits_{\bf x}\|{\bf Ax}\|$ subject to $\|{\bf x}\|=1$ and ${\bf Bx} \geq {\bf 0}$

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Rodrigo de Azevedo
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1 vote
1 answer
609 views

Hilbert Space Algebraic Tensor Product is not Complete - Proven Example?

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6 votes
1 answer
173 views

Is the countable box product of real lines $\mathbb{R}^\omega$ Strongly KC?

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mezzoctane
  • 3,030
3 votes
2 answers
334 views

Question on faithful representation and irreducible characters

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Dhairya Kumar
  • 2,082
0 votes
1 answer
67 views

Understanding why a function is analytic at a point

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Aromath
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3 votes
1 answer
3k views

Differential equation (Brachistochrone problem)

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JJacquelin
  • 69.5k
1 vote
1 answer
80 views

What is the basic reproduction number ($R_0$) for a logistic function?

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J.G.
  • 119k
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0 answers
134 views

Conjecture : $\forall n>2, \max_{d \mid (2^n + 3)} v_2(d+9)<3\log(n)$

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Lhachimi
  • 1,106
6 votes
1 answer
623 views

Multiplying both sides of an equation in proofs

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3 votes
2 answers
152 views

Is there a name for the function $x^2 \cdot\operatorname{sign}(x)$?

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JonathanZ
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5 votes
1 answer
85 views

Basic Question about Polygonal Arcs

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Christophe Boilley
  • 13.6k
4 votes
1 answer
70 views

Growth rate of $f(n)=-\sum_{d|n}\frac{\mu(d)\log(d)}{d}\ll \log \log n$

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davidlowryduda♦
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8 votes
2 answers
490 views

A triangle inscribed in a sinusoid is necessarily obtuse

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