Garmekain's user avatar
Garmekain's user avatar
Garmekain's user avatar
Garmekain
  • Member for 7 years, 6 months
  • Last seen more than a week ago
48 votes
1 answer
7k views

Why is that if every row of a matrix sums to 1, then the rows of the inverse matrix sums to 1 too?

11 votes
2 answers
795 views

How is the similarity of the structure of two functions defined?

7 votes
1 answer
145 views

What values of $a,b\in\mathbb{Z^+}$ satisfy $a^b=b^a+1$?

7 votes
3 answers
203 views

Approximating $\pi$ and $\ln 2$ with $I_k=\int_0^\infty \left(\text{sech}x\tanh\tfrac12x\right)^k\,dx$ for integer $k$

6 votes
2 answers
302 views

What are $f\circ\emptyset$ and $\emptyset\circ f$ if $\circ$ is function composition and $f$ is any function?

6 votes
0 answers
265 views

Proof that every even integer $>2$ can be expressed as the sum of two times some prime $p$ and the distance between $p$ and a greater or equal prime?

6 votes
1 answer
93 views

Trouble understanding topological groups.

5 votes
4 answers
360 views

Does the set $S=\{x\mid x\in S\}$ exist?

5 votes
1 answer
212 views

Evaluate $\frac{1}{2}\int_0^1\int_{-1}^1\frac{1}{\sqrt{1-x^2}}\int_0^{\sqrt{1-x^2}}\sqrt{(x-h)^2+y^2}dy dx dh$

5 votes
1 answer
1k views

Prove or disprove $p(|T|)\neq 0\longrightarrow \exists v\in V_c:R(v)\neq 0$

5 votes
2 answers
1k views

How can the set of all graphs be the same size as its power set?

5 votes
1 answer
490 views

Does symmetry of the Green's function of some operator imply that the operator is hermitian?

4 votes
1 answer
86 views

Does every module define a category?

4 votes
4 answers
6k views

Prove the cardinality of $\mathbb{Z}$ and $\mathbb{N}$ is the same.

4 votes
0 answers
59 views

Methods for finding some function $h$ with the property that, given two functions $f,g$, then $h\circ f=g\circ h$ is true?

4 votes
1 answer
88 views

The recursive systems of equations with the following form, have they ever been considered?

3 votes
1 answer
561 views

Has anyone ever used the size of the symmetric difference of two sets $X,Y$ as a metric on finite sets?

3 votes
1 answer
147 views

How is that $A^n A\neq A A^n$?

3 votes
1 answer
74 views

Formalization of proof that there exists no bijective map from the integers to the naturals such that the ordering is preserved?

3 votes
2 answers
9k views

Infinite number of irrational numbers between 0 and 1?

3 votes
11 answers
415 views

Can we say that $\frac{0}{0}$ is every number?

3 votes
0 answers
70 views

Prove $\exists T\neq \emptyset,\sum\limits_{v\in V}C=0$

3 votes
1 answer
401 views

Can a finite number have an uncountable infinite amount of non-zero terms? [duplicate]

3 votes
3 answers
2k views

Some examples of functions that are their own inverse? [duplicate]

3 votes
1 answer
88 views

Is it possible to have a monoid with a proper class as the collection of elements?

3 votes
2 answers
151 views

Integer solutions for $\frac{n(n-1)}2=m^2-1$

3 votes
0 answers
79 views

Complex scalar fields on real manifolds.

2 votes
1 answer
130 views

Is there a name for this "homomorphism" between vector spaces over different fields?

2 votes
1 answer
41 views

Finding real functions satisfying $f(x,z)^2=\int_\Bbb R f(x,y)f(y,z)dy$?

2 votes
3 answers
41 views

Homomorphism between integers and $(-1,1)$ under any operation contains an irrational point

1
2 3 4 5 6