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alkabary
  • Member for 10 years, 9 months
  • Last seen more than 3 years ago
14 votes
3 answers
5k views

Prove that $2$, $3$, $1+ \sqrt{-5}$, and $1-\sqrt{-5}$ are irreducible in $\mathbb{Z}[\sqrt{-5}]$.

11 votes
2 answers
5k views

Difference between Stabilizer and Centralizer?

11 votes
4 answers
5k views

Does a Conjugacy Class always contain an element and its inverse?

11 votes
2 answers
10k views

Number of ways to pair off $2n$ points such that no chords intersect

10 votes
3 answers
6k views

Finding the number of non-decreasing sequences.

10 votes
3 answers
3k views

Trying mathematical induction with $3n+1$ conjecture

9 votes
1 answer
1k views

Presentation of a group question

8 votes
3 answers
790 views

Why $\lim_{x\to -\infty} \frac{x^3}{\sqrt{x^6+4}} =-1 $ and not $1$?

7 votes
1 answer
481 views

Division with Gaussian integers

6 votes
1 answer
631 views

Inverses of elements in group algebras

5 votes
2 answers
169 views

Do I add or multiply in this question?

5 votes
2 answers
10k views

Prove the generating function for the Catalan number sequence is $f(x) = \frac{1 -\sqrt{1-4x}}{2x}$

5 votes
5 answers
636 views

Why aren't there any solutions?

4 votes
1 answer
854 views

In how many ways can two dozen identical robots be assigned to four assembly lines?

4 votes
2 answers
1k views

Latin square property sufficient?

4 votes
1 answer
3k views

Using Fermats prime numbers to prove that there is infinitely many prime numbers [duplicate]

4 votes
1 answer
158 views

Proving irreducibility of representations using matrix representation

4 votes
1 answer
2k views

Prove that a graph is a maximal planar graph if and only if $e = 3v − 6$

4 votes
4 answers
621 views

Pythagorean triples

4 votes
3 answers
2k views

Showing that order of $SL_2(Z_3)$ is 24

3 votes
4 answers
546 views

Is it always true that $(a,b,c)(a,b,c) = (a,c,b)$?

3 votes
1 answer
485 views

Center in relation to the Centralizer

3 votes
3 answers
411 views

Why is this following integral not zero ?

3 votes
2 answers
44k views

Finding the order of all the elements in Group $\mathbb{Z}_{12}$

3 votes
3 answers
3k views

Proving that the Gaussian integers have no zero divisors

3 votes
1 answer
6k views

Quotient field of gaussian integers

3 votes
4 answers
2k views

How to show that $\cos\frac{2\pi}{n} + \cos\frac{4\pi}{n} + \ldots+ \cos\frac{2\pi(n-1)}{n} = -1$ for all positive integers $n$?

3 votes
2 answers
853 views

Let G be a finite cyclic group of order n. If d is a positive divisor of n , prove that x^d = e has exactly d distinct solutions in G

3 votes
1 answer
2k views

Show in a maximal planar graph every face is a triangle.

3 votes
1 answer
9k views

The number of pendant vertices in a tree

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