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Student
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  • België
7 votes
3 answers
278 views

Pointwise convergence of sequence $(f_n)_n$ of functions to $f$ and changing limits

6 votes
3 answers
142 views

Supplementary exercise 51, chapter 3 from 'A walk through combinatorics' 4th edition

5 votes
1 answer
6k views

Tensor product of localization is isomorphic to localization of tensor product

5 votes
2 answers
758 views

Compute $5!25! \mod 31$

5 votes
5 answers
169 views

Computing $7^{13} \mod 40$

4 votes
2 answers
495 views

Inverse image of a Noetherian module under a module morphism

4 votes
1 answer
413 views

isomorphic extension fields of the $p$-adic numbers

4 votes
2 answers
64 views

If $x = y^3$ in $\mathbb{Z} + \frac{-1 + \sqrt{-3}}{2}\mathbb{Z}$, then there is some $w \in \mathbb{Z} + \sqrt{-3}\mathbb{Z}$ such that $x = w^3$.

4 votes
1 answer
96 views

Subgroups of finitely generated group are not necessarily finitely generated (proof).

4 votes
2 answers
518 views

Restriction of homomorphism to finite index subgroup gives finite index subgroup of kernel

4 votes
1 answer
395 views

Prove that the following map has at least $k-2$ fixed points

4 votes
1 answer
313 views

Boundary $\partial F_n$ of a free group $F_n$

3 votes
1 answer
122 views

automorphism of free group $F_n$ fixing $F_{n-1}$ and image of $n$th generator

3 votes
2 answers
102 views

image of homomorphism contains free group, then so does domain

3 votes
1 answer
363 views

$x_n \to x \in \mathbb{R}$ and $y_n \to 0 $. What about $\frac{x_n}{y_n}$?

3 votes
2 answers
4k views

Why is this function only differentiable at zero?

3 votes
1 answer
109 views

components of subgraph determine subgroups up to conjugacy

3 votes
3 answers
445 views

Prove that $\sum_{k = 0}^{49}(-1)^k\binom{99}{2k} = -2^{49}$

3 votes
0 answers
135 views

showing elements in $\mathbb{Z}+\frac{1 + \sqrt{5}}{2}\mathbb{Z}$ are associated

3 votes
0 answers
74 views

Factoring $a + b\frac{1 + \sqrt{5}}{2}$ if $a^2 + ab - b^2 = a+b$

3 votes
2 answers
128 views

Proving that $a+b\sqrt{-3}$ is a cube if $a^2 + 3b^2 = c^3$

3 votes
1 answer
120 views

Compute $50! \mod 2014$

3 votes
1 answer
438 views

Proof about positive semi-definite matrix

3 votes
2 answers
933 views

Proving $(x_1 - a_1, \ldots, x_n -a_n)$ is a maximal ideal [duplicate]

3 votes
3 answers
145 views

Question about definition of graded ring

3 votes
1 answer
360 views

Non-singular zeros are isolated.

3 votes
4 answers
4k views

Number of elements of order 2

3 votes
3 answers
82 views

Find all couples $(a,b) \in \mathbb{Z}^2$

2 votes
2 answers
469 views

If $m^2 +n^2 - m$ is a multiple of $mn$ and $p$ divides $m$ then $p^2$ divides $m$

2 votes
2 answers
165 views

finding smallest natural number $n$ such that $n \equiv 1023 \bmod 2015$ and $n \equiv 1302 \bmod 2016$