User AgCl - Mathematics Stack Exchange

346 votes

36 answers

33k views

A challenge by R. P. Feynman: give counter-intuitive theorems that can be translated into everyday language

asked Jul 21, 2010 at 4:24

122 votes

8 answers

15k views

Are the "proofs by contradiction" weaker than other proofs?

asked Jul 21, 2010 at 3:19

43 votes

4 answers

5k views

If all sets were finite, how could the real numbers be defined?

asked Jul 22, 2010 at 15:58

34 votes

4 answers

9k views

Sum of two periodic functions

asked Jul 28, 2010 at 23:44

13 votes

1 answer

9k views

Geometric multiplicity of an eigenvalue

asked Oct 8, 2010 at 2:33

12 votes

2 answers

3k views

Khayyam's work on cubic equations

asked Nov 25, 2010 at 18:33

12 votes

2 answers

357 views

Writing $f(x,y)$ as $\Phi(g(x) + h(y))$

asked Nov 29, 2010 at 2:06

11 votes

4 answers

857 views

Sets of integers in which every element is the sum of two others

asked Aug 17, 2010 at 11:57

10 votes

2 answers

1k views

Every real sequence is the derivative sequence of some function

asked Nov 17, 2010 at 0:37

9 votes

2 answers

690 views

A numerical optimization problem with a convolution in the constraint

asked Oct 18, 2010 at 18:57

8 votes

1 answer

878 views

Integer translates of a scaling function

asked Oct 1, 2010 at 3:48

7 votes

1 answer

2k views

Quadratic minimization in a Hilbert space

asked Nov 18, 2010 at 7:38

6 votes

4 answers

4k views

Dividing a disk into $7$ equal pieces with $3$ line segments

asked Aug 6, 2010 at 20:40

4 votes

1 answer

2k views

Rigorous definition of convolution with the unit doublet

asked Nov 9, 2010 at 0:43

3 votes

2 answers

949 views

Choice function on $\mathcal P (\mathbb R) \setminus \{ \emptyset\}$

asked Aug 22, 2010 at 11:11

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15 Questions

A challenge by R. P. Feynman: give counter-intuitive theorems that can be translated into everyday language

Are the "proofs by contradiction" weaker than other proofs?

If all sets were finite, how could the real numbers be defined?

Sum of two periodic functions

Geometric multiplicity of an eigenvalue

Khayyam's work on cubic equations

Writing $f(x,y)$ as $\Phi(g(x) + h(y))$

Sets of integers in which every element is the sum of two others

Every real sequence is the derivative sequence of some function

A numerical optimization problem with a convolution in the constraint

Integer translates of a scaling function

Quadratic minimization in a Hilbert space

Dividing a disk into $7$ equal pieces with $3$ line segments

Rigorous definition of convolution with the unit doublet

Choice function on $\mathcal P (\mathbb R) \setminus \{ \emptyset\}$