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Danny
  • Member for 10 years, 10 months
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27 votes
13 answers
8k views

Proving that $\mathbb{Z}[x]$ and $\mathbb{Q}[x]$ are not isomorphic.

12 votes
3 answers
11k views

Proving that $\mathbb{F}^\infty$ is infinite-dimensional.

12 votes
3 answers
8k views

Examples of Infinite Boolean Rings

6 votes
6 answers
1k views

Question About Dedekind Cuts

6 votes
2 answers
5k views

Prove null $T^k$ = null $T$ and range $T^k$ = range $T$

4 votes
1 answer
66 views

Question regarding nilpotent ideals of a ring.

4 votes
1 answer
326 views

When is a curve parametrizable?

3 votes
1 answer
132 views

How can I show that $x^4+6$ is reducible over $\mathbb{R}$?

2 votes
1 answer
258 views

Do there exist polynomial rings with nonzero prime ideals that are not maximal?

2 votes
3 answers
1k views

Can we find an element of infinite order in a symmetric group of infinite order?

2 votes
0 answers
1k views

Products of Laurent Series

1 vote
2 answers
77 views

How do I show $\sqrt{n} \not \in O(\log{n})$?

1 vote
1 answer
552 views

Proof that $\sigma$-algebras are closed under countable disjoint unions

1 vote
1 answer
146 views

Find $\Gamma$ such that any model of $\Gamma$ has an infinite domain.

1 vote
4 answers
424 views

Proving $\lim\limits_{n \to \infty}[\sqrt{n^2 + 1} - n] = 0$

1 vote
3 answers
161 views

Finding eigenvalues.

1 vote
1 answer
1k views

Prove that if R and S are nonzero rings then $R\times S$ is never a field.

0 votes
1 answer
163 views

Proving that there exists a function $f: \mathbb{N} \rightarrow \mathbb{N}$ that is not URM-computable.

0 votes
0 answers
95 views

Proving that every smooth manifold is metrizable

0 votes
0 answers
31 views

Calculating the elements of $H_1(G)$ for a graph

0 votes
1 answer
121 views

Fulton and Harris -- Exercise 1.1