User Simon Wadsley

22 votes

Accepted

Are there any finitely generated artinian modules that are not Noetherian?

answered Apr 14, 2011 at 13:36

16 votes

D-modules on rigid analytic spaces

answered Mar 1, 2011 at 9:49

15 votes

Accepted

Isomorphic but non-conjugate subgroups of $GL(n,\mathbb{Z})$ ?

answered Mar 19, 2012 at 11:51

13 votes

Can we categorify the equation (1 - t)(1 + t + t^2 + ...) = 1?

answered Oct 20, 2009 at 20:17

11 votes

Different definitions of the dimension of an algebra

answered Oct 26, 2009 at 8:30

10 votes

Can an infinite conjugacy class in a group split into more than one conjugacy class in some subgroup of finite index?

answered Nov 20, 2009 at 13:48

10 votes

Why should the tensor product of $\mathcal{D}_X$-modules over $\mathcal{O}_X$ be a $\mathcal{D}_X$-module?

answered Dec 21, 2016 at 14:19

10 votes

Accepted

What kind of algebraic object is $\mathcal{D}_X$? (algebra of diifferential operators). What's special about modules over it?

answered Dec 21, 2016 at 17:07

7 votes

Different definitions of the dimension of an algebra

answered Oct 26, 2009 at 9:05

7 votes

When are finite-dimensional representations on Hilbert spaces completely reducible?

answered Jul 14, 2023 at 11:33

7 votes

Faithful flatness and non-commutative algebras

answered Dec 5, 2023 at 15:53

6 votes

Accepted

Adjoint action on the universal enveloping algebra and the PBW theorem

answered Aug 16, 2023 at 21:37

6 votes

Accepted

Prove that the ideal of $\mathbb{C}G$ generated by a family of elements $\lbrace p_i\rbrace_{i=1}^n$ is equal to $\mathbb{C}G$

answered Sep 26, 2023 at 11:16

6 votes

Generalization of the two bucket puzzle

answered Nov 17, 2009 at 9:31

6 votes

Accepted

Polycyclic group not of type $FP_\infty$

answered Feb 12, 2013 at 12:20

6 votes

Maximal Ideals in Formal Laurent Series Rings?

answered Mar 11, 2011 at 11:12

5 votes

$\mathbb{Z}G$ (left) Noetherian$\Rightarrow$ $\ell^1(G)$ is a flat (right) $\mathbb{Z}G$-module?

answered Sep 17, 2013 at 8:38

5 votes

Accepted

Non-free projective modules for a Universal Enveloping Algebra?

answered Oct 22, 2009 at 10:03

5 votes

Accepted

Testing ideal membership in the Weyl algebra: a simple example

answered Sep 20, 2019 at 9:31

4 votes

Accepted

$R/I\cong R/\text{Ann}_R(R/I)$ but $I\neq\text{Ann}_R(R/I)$

answered Sep 18, 2020 at 9:01

4 votes

Accepted

Motivation and reference for Brauer algebras

answered Dec 23, 2020 at 13:33

4 votes

Accepted

What's the relation between pseudo-compact and admissible rings?

answered Feb 22, 2023 at 16:26

4 votes

Accepted

Is every endomorphism of the sheaf of holomorphic functions on a disk a differential operator?

answered Feb 19, 2018 at 13:00

4 votes

Accepted

Zero-divisors in a graded Lie algebra

answered Jun 4, 2013 at 12:31

4 votes

Accepted

Dual of a bimodule

answered Aug 27, 2019 at 15:37

4 votes

Accepted

Bi-embeddability vs. isomorphism

answered Oct 15, 2009 at 15:31

3 votes

Accepted

Separable and finitely generated projective but not Frobenius?

answered Oct 23, 2009 at 11:18

3 votes

How does one identify properties of objects with good "inheritance"?

answered Nov 10, 2009 at 9:31

3 votes

Relation between Lie Algebra Cohomology and Number of Relations of a Cyclic Module?

answered Nov 19, 2009 at 20:55

3 votes

Accepted

About the construction of the Universal Enveloping Lie Algebroid

answered Jun 19, 2014 at 9:28

Stack Exchange Network

52 Answers

Are there any finitely generated artinian modules that are not Noetherian?

D-modules on rigid analytic spaces

Isomorphic but non-conjugate subgroups of $GL(n,\mathbb{Z})$ ?

Can we categorify the equation (1 - t)(1 + t + t^2 + ...) = 1?

Different definitions of the dimension of an algebra

Can an infinite conjugacy class in a group split into more than one conjugacy class in some subgroup of finite index?

Why should the tensor product of $\mathcal{D}_X$-modules over $\mathcal{O}_X$ be a $\mathcal{D}_X$-module?

What kind of algebraic object is $\mathcal{D}_X$? (algebra of diifferential operators). What's special about modules over it?

Different definitions of the dimension of an algebra

When are finite-dimensional representations on Hilbert spaces completely reducible?

Faithful flatness and non-commutative algebras

Adjoint action on the universal enveloping algebra and the PBW theorem

Prove that the ideal of $\mathbb{C}G$ generated by a family of elements $\lbrace p_i\rbrace_{i=1}^n$ is equal to $\mathbb{C}G$

Generalization of the two bucket puzzle

Polycyclic group not of type $FP_\infty$

Maximal Ideals in Formal Laurent Series Rings?

$\mathbb{Z}G$ (left) Noetherian$\Rightarrow$ $\ell^1(G)$ is a flat (right) $\mathbb{Z}G$-module?

Non-free projective modules for a Universal Enveloping Algebra?

Testing ideal membership in the Weyl algebra: a simple example

$R/I\cong R/\text{Ann}_R(R/I)$ but $I\neq\text{Ann}_R(R/I)$

Motivation and reference for Brauer algebras

What's the relation between pseudo-compact and admissible rings?

Is every endomorphism of the sheaf of holomorphic functions on a disk a differential operator?

Zero-divisors in a graded Lie algebra

Dual of a bimodule

Bi-embeddability vs. isomorphism

Separable and finitely generated projective but not Frobenius?

How does one identify properties of objects with good "inheritance"?

Relation between Lie Algebra Cohomology and Number of Relations of a Cyclic Module?

About the construction of the Universal Enveloping Lie Algebroid