User shadow10

9

23

votes

3

answers

625

views

A game on a graph

Dec 29 at 5:45 URL 4,291

8

21

votes

2

answers

2k

views

A functional equation with no solution

calculus derivatives functional-equations

Nov 13 '14 at 17:51 travelingbones 189

4

16

votes

4

answers

381

views

An inequality on sequences with each term dividing sum of two neighbouring terms

number-theory inequality

Jul 26 '14 at 7:04 r9m 16.9k

6

13

votes

1

answer

162

views

A claim that a is a square

number-theory inequality

Jan 9 '14 at 18:36 benh 6,399

5

10

votes

1

answer

463

views

A Shapiro type inequality

inequality contest-math

Feb 12 '18 at 5:52 Sergey Sadov 1

4

9

votes

2

answers

434

views

If the sum of cubes of $a,b,c,d$ is $1$, then $\frac{1}{1-bcd}+\frac{1}{1-cda}+\frac{1}{1-dab}+\frac{1}{1-abc}\le \frac{16}{3}$

multivariable-calculus inequality substitution symmetric-polynomials uvw

Oct 25 '18 at 7:05 Michael Rozenberg 177k

3

8

votes

1

answer

578

views

If $P(x)-2^n$ has a rational root for each $n\in\mathbb{N}$, is $P$ linear?

polynomials roots

Oct 12 at 2:04 Qiaochu Yuan 341k

2

8

votes

3

answers

327

views

An integral inequality with inverse

integral-inequality

Jul 18 '14 at 18:23 Théophile 24.5k

4

8

votes

1

answer

120

views

A question of rationality

calculus real-analysis functions

Apr 22 '14 at 15:25 fgp 19.3k

2

7

votes

2

answers

128

views

Inequality $\cos x+\cos y+\cos z=0$ and $\cos{3x}+\cos{3y}+\cos{3z}=0$ prove that $\cos{2x}\cdot \cos{2y}\cdot \cos{2z}\le 0$

trigonometry inequality

Feb 18 '20 at 7:36 wuyudi 945

5

7

votes

1

answer

1k

views

IMO 2014 problem 3, first day

contest-math euclidean-geometry

Feb 25 '15 at 9:53 Community♦ 1

3

7

votes

1

answer

195

views

Graphs with uncountably many vertices

elementary-set-theory graph-theory infinite-graphs

Aug 22 '14 at 21:59 hot_queen 6,792

4

7

votes

1

answer

189

views

Size of a family of sets $F$ such that if $|A\cap X|=|B\cap X|$ for all $X\in F$, then $A=B$

combinatorics probabilistic-method

Aug 3 '14 at 5:27 Community♦ 1

1

7

votes

2

answers

344

views

Finding all possible values of $x^4+y^4+z^4$

algebra-precalculus

Jun 3 '14 at 12:47 user642796 48.1k

5

6

votes

3

answers

165

views

If $a+b+c+d=4$, then $\sum\frac{1}{a+3}\le \frac{1}{abcd}$

algebra-precalculus inequality symmetric-polynomials

Feb 18 '20 at 19:16 Michael Rozenberg 177k

2

6

votes

1

answer

190

views

Almost sure convergence through subsequences

probability-theory independence borel-cantelli-lemmas

Nov 12 '15 at 8:45 BCLC 1

7

6

votes

3

answers

189

views

An uncanny inequality with Gamma function

inequality contest-math

Oct 4 '14 at 0:26 robjohn♦ 306k

4

6

votes

2

answers

398

views

Unique solution comes out to be trace

linear-algebra

Sep 28 '14 at 11:08 user153012 11.3k

6

votes

1

answer

119

views

Finding all such polynomials under a gcd condition

elementary-number-theory polynomials contest-math

Jul 12 '14 at 20:00 Calvin Lin 53.5k

3

6

votes

1

answer

115

views

A formula for $\pi$ and an inequality

inequality definite-integrals pi

Jun 20 '14 at 16:57 Daniel Fischer♦ 193k

3

6

votes

1

answer

59

views

Polygonal line in a square

probability

Jun 16 '14 at 11:57 Greg Martin 53.9k

4

5

votes

1

answer

203

views

Existence of a continuous surjective map [duplicate]

analysis algebraic-topology

Dec 13 '17 at 17:42 Mathis 837

2

5

votes

1

answer

185

views

Squeezing an open set and a compact set between two sets

general-topology compactness

Aug 15 '15 at 9:38 Dominik 18.6k

3

5

votes

1

answer

112

views

Inequality on length of intervals

measure-theory contest-math combinatorial-geometry

Dec 30 '14 at 22:50 Mizar 5,531

4

5

votes

1

answer

108

views

Find all such functions defined on the space

geometry contest-math 3d

Jul 9 '14 at 12:18 hmakholm left over Monica 268k

1

5

votes

1

answer

160

views

Evaluating a limit involving integral

calculus limits

Jun 14 '14 at 16:09 RRL 76.3k

1

4

votes

1

answer

320

views

Two problems related to continuity of a metric from Munkres' topology book

general-topology metric-spaces continuity

Jun 2 '15 at 7:45 T. Eskin 7,435

1

4

votes

2

answers

2k

views

Open and closed subset of $\mathbb{R}$

general-topology

Sep 2 '14 at 19:36 triple_sec 20.4k

2

4

votes

2

answers

124

views

A game with checkers

combinatorics

Jul 23 '14 at 17:23 Denis 6,367

3

4

votes

1

answer

255

views

A problem from Komal

number-theory radicals

Jul 14 '14 at 16:49 cactus314 22.5k

Stack Exchange Network

current community

your communities

more stack exchange communities

Next privilege

Next badge

139 Questions

A game on a graph

A functional equation with no solution

An inequality on sequences with each term dividing sum of two neighbouring terms

A claim that a is a square

A Shapiro type inequality

If the sum of cubes of $a,b,c,d$ is $1$, then $\frac{1}{1-bcd}+\frac{1}{1-cda}+\frac{1}{1-dab}+\frac{1}{1-abc}\le \frac{16}{3}$

If $P(x)-2^n$ has a rational root for each $n\in\mathbb{N}$, is $P$ linear?

An integral inequality with inverse

A question of rationality

Inequality $\cos x+\cos y+\cos z=0$ and $\cos{3x}+\cos{3y}+\cos{3z}=0$ prove that $\cos{2x}\cdot \cos{2y}\cdot \cos{2z}\le 0$

IMO 2014 problem 3, first day

Graphs with uncountably many vertices

Size of a family of sets $F$ such that if $|A\cap X|=|B\cap X|$ for all $X\in F$, then $A=B$

Finding all possible values of $x^4+y^4+z^4$

If $a+b+c+d=4$, then $\sum\frac{1}{a+3}\le \frac{1}{abcd}$

Almost sure convergence through subsequences

An uncanny inequality with Gamma function

Unique solution comes out to be trace

Finding all such polynomials under a gcd condition

A formula for $\pi$ and an inequality

Polygonal line in a square

Existence of a continuous surjective map [duplicate]

Squeezing an open set and a compact set between two sets

Inequality on length of intervals

Find all such functions defined on the space

Evaluating a limit involving integral

Two problems related to continuity of a metric from Munkres' topology book

Open and closed subset of $\mathbb{R}$

A game with checkers

A problem from Komal