User C Monsour

36 votes

Accepted

In classical geometry why is a line considered to be parallel to itself?

answered Apr 17, 2018 at 22:39

27 votes

Why is it important for a matrix to be square?

answered Jun 8, 2018 at 1:02

15 votes

Why is $\operatorname{Var}[X]≤(b−a)^2/4$ if $X$ is a random variable with values between $[a,b]$

answered May 20, 2018 at 19:37

13 votes

Accepted

Is there a reason why $Z(G)$ is named the "centre" of a group?

answered Jan 15, 2019 at 22:36

10 votes

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Problem in the "proof" of Eisenstein's criterion on irreducibility.

answered Apr 29, 2018 at 10:07

9 votes

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Why is there a difference between life-insurance and general (non-life) insurance mathematics?

answered Jun 15, 2019 at 13:32

8 votes

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Covering a sphere with spherical caps

answered Apr 28, 2018 at 5:32

8 votes

What is the abelianization of $\langle x,y,z\mid x^2=y^2z^2\rangle?$

answered Aug 20, 2018 at 2:54

7 votes

Burnside's transfer theorem in group theory

answered Jul 8, 2018 at 2:45

6 votes

Degree of Field Extension $[\mathbb{Q}(\sqrt[3]{2}):\mathbb{Q}]$

answered Jul 12, 2018 at 1:10

6 votes

Integer solutions to the non linear Diophantine equation $x^5+y^5=47$

answered Apr 28, 2018 at 18:44

6 votes

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Does there exist a measurable function with a specific property?

answered May 5, 2018 at 19:06

6 votes

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Proof about relatively prime numbers.

answered May 15, 2018 at 3:09

6 votes

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A group of order $p^nm$ isn't simple

answered Sep 26, 2018 at 3:20

6 votes

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Group action on a set that has smaller cardinality than group's one

answered Oct 4, 2018 at 15:06

5 votes

Accepted

Group theory conjectures

answered Apr 24, 2018 at 3:40

5 votes

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Prove that there is no simple group of order $144$

answered Jun 26, 2018 at 0:20

5 votes

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How to prove: if $G$ finite, $P$ a subgroup or order $p$ and $P = C_G(P)$ then $P$ is a Sylow $p$-subgroup of $G$

answered Jun 21, 2018 at 23:54

5 votes

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Can someone explain to me why $\mathcal P(\mathcal P(\emptyset)) = \{\emptyset,\{\emptyset\}\}$?

answered May 19, 2018 at 6:49

5 votes

SL(2,5) and SL(2,11)

answered Jul 5, 2018 at 15:56

4 votes

Every group of order $150$ has a normal subgroup of order $25$

answered Aug 14, 2018 at 11:42

4 votes

Examples of finite groups that are not a semidirect product

answered Oct 31, 2020 at 8:18

4 votes

Categorization of Gaussian primes

answered May 20, 2018 at 23:57

4 votes

Accepted

Determining the elements of the group $H:=\langle a\rangle \cap \langle b\rangle$

answered Jun 27, 2018 at 0:47

4 votes

To show a particular element is the unit of a ring

answered Jul 10, 2018 at 0:48

4 votes

Proving there are an infinite number of irreducible monic polynomials over a field

answered May 12, 2018 at 5:03

4 votes

Accepted

Does $\sum\limits_{n=1}^{\infty}\frac{\cos^{2}(n+1)}{n}$ converge?

answered May 6, 2018 at 5:43

4 votes

Finding maximal in $\Bbb Z[x]$

answered Oct 6, 2018 at 13:23

4 votes

Accepted

What is the automorphism group of $D_5$ (and, more generally, of $D_n$)?

answered Oct 16, 2018 at 3:26

4 votes

Accepted

Show that a group of order 440 has a unique subgroup of order 55

answered Oct 23, 2018 at 0:16

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301 Answers

In classical geometry why is a line considered to be parallel to itself?

Why is it important for a matrix to be square?

Why is $\operatorname{Var}[X]≤(b−a)^2/4$ if $X$ is a random variable with values between $[a,b]$

Is there a reason why $Z(G)$ is named the "centre" of a group?

Problem in the "proof" of Eisenstein's criterion on irreducibility.

Why is there a difference between life-insurance and general (non-life) insurance mathematics?

Covering a sphere with spherical caps

What is the abelianization of $\langle x,y,z\mid x^2=y^2z^2\rangle?$

Burnside's transfer theorem in group theory

Degree of Field Extension $[\mathbb{Q}(\sqrt[3]{2}):\mathbb{Q}]$

Integer solutions to the non linear Diophantine equation $x^5+y^5=47$

Does there exist a measurable function with a specific property?

Proof about relatively prime numbers.

A group of order $p^nm$ isn't simple

Group action on a set that has smaller cardinality than group's one

Group theory conjectures

Prove that there is no simple group of order $144$

How to prove: if $G$ finite, $P$ a subgroup or order $p$ and $P = C_G(P)$ then $P$ is a Sylow $p$-subgroup of $G$

Can someone explain to me why $\mathcal P(\mathcal P(\emptyset)) = \{\emptyset,\{\emptyset\}\}$?

SL(2,5) and SL(2,11)

Every group of order $150$ has a normal subgroup of order $25$

Examples of finite groups that are not a semidirect product

Categorization of Gaussian primes

Determining the elements of the group $H:=\langle a\rangle \cap \langle b\rangle$

To show a particular element is the unit of a ring

Proving there are an infinite number of irreducible monic polynomials over a field

Does $\sum\limits_{n=1}^{\infty}\frac{\cos^{2}(n+1)}{n}$ converge?

Finding maximal in $\Bbb Z[x]$

What is the automorphism group of $D_5$ (and, more generally, of $D_n$)?

Show that a group of order 440 has a unique subgroup of order 55