Pavel Čoupek's user avatar
Pavel Čoupek's user avatar
Pavel Čoupek's user avatar
Pavel Čoupek
  • Member for 10 years, 10 months
  • Last seen more than 1 year ago
16 votes

$\mathbb{Z}$ is Noetherian but not Artinian

14 votes
Accepted

Double Complex Where $\mathrm{Tot}^\prod$ is Acyclic but $\mathrm{Tot}^\oplus$ is not

10 votes
Accepted

Algebraic vs. Integral Closure of a Ring

10 votes
Accepted

Do these facts about $\mathbb{Q}/\mathbb{Z}$ generalize to more general cases?

8 votes
Accepted

Unique prime ideal implies every element is nilpotent or a unit.

8 votes
Accepted

$k$-algebra morphisms from formal power series ring

7 votes
Accepted

Non-commutative ring Local Ring

7 votes
Accepted

If $\varphi(I)$ is an Ideal $\forall I $ ideal of $A$, is $\varphi$ surjective?

7 votes

How to define the natural map on the second page of a spectral sequence?

6 votes

Non-abelian Group with infinite exponent in which every proper subgroup has finite exponent

6 votes

Are there any finite non-abelian group with one subgroup of each size ?

6 votes
Accepted

Number of generators in a tensor product

6 votes
Accepted

Group $G$ such that there is a proper subgroup containing every other proper subgroup of $G$

6 votes
Accepted

What are some examples of "exotic" algebraic structures?

6 votes
Accepted

Hilbert's Nullstellensatz implies $I(Z(I)) = \sqrt{I}$

6 votes
Accepted

Is the Universal Property Alone Enough to Use Tensor Products?

5 votes
Accepted

Question from $p$-adic HodgeTheory, linear algebra data

5 votes
Accepted

Several questions about direct limit of rings

5 votes
Accepted

A module with infinitely many associated primes.

5 votes
Accepted

Functors which are non-isomorphic but whose derived functors are isomorphic

5 votes
Accepted

locally free resolution of coherent sheaf on quasi-projective scheme

5 votes
Accepted

Is Yoneda Lemma a characterization of isomorphism?

5 votes

decomposition group and inertia group, the minimal polynomial,surjectivity of the map $D_{M/P}\rightarrow Gal$

4 votes
Accepted

Essential smallness of finitely presentable subcategory

4 votes

Why is $\bigcap_{\mathfrak{p} \in D(f)} A_\mathfrak{p} \subset A_f$?

4 votes
Accepted

Graded rings: coproduct vs tensor product

4 votes

Retraction and direct limit

4 votes
Accepted

Is $k[x,y]$ isomorphic to a subring of $k[z]$?

4 votes
Accepted

Must certain rings be isomorphic to $\mathbb{Z}[\sqrt{a}]$ for some $a$

4 votes
Accepted

Does first isomorphism theorem hold in the category of normed linear spaces?

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