User Ehsaan

27 votes

0 answers

548 views

Is there a group $G$ for which $\mathrm{Aut}(G) \simeq (\mathbb{R},+)$?

asked Nov 27, 2020 at 15:48

11 votes

3 answers

729 views

Examples of subgroups where it's nontrivial to show closure under multiplication?

asked Apr 27, 2019 at 14:07

10 votes

1 answer

400 views

Morita equivalent rings have homeomorphic spectra?

asked Oct 7, 2015 at 19:17

8 votes

2 answers

2k views

Prove that semi-simple rings are Dedekind-finite

asked May 22, 2013 at 19:15

8 votes

1 answer

977 views

Nontrivial examples of pro-$p$ groups

asked Dec 1, 2014 at 1:08

7 votes

1 answer

875 views

If $N$ and $G/N$ are virtually solvable, then $G$ is virtually solvable?

asked Jul 4, 2013 at 18:13

7 votes

1 answer

3k views

Inducing homomorphisms on localizations of rings/modules

asked Feb 20, 2014 at 4:49

7 votes

3 answers

2k views

Quotient of locally free sheaf is locally free?

asked Aug 16, 2014 at 23:21

7 votes

2 answers

352 views

Algebraic results using lower K-theory as a blackbox

asked Nov 1, 2014 at 21:25

6 votes

1 answer

793 views

Rank of projective module defined as the smallest $n$ such that $P$ is a direct summand of $R^n$

asked Oct 11, 2014 at 18:08

5 votes

1 answer

186 views

If the torsion subset of a group has "finite index", is the group torsion?

asked Jan 2, 2020 at 22:34

4 votes

1 answer

332 views

If $R$ is a simple ring, is every corner $eRe$ simple?

asked Jul 20, 2015 at 3:59

4 votes

2 answers

140 views

If $H$ is a Hilbert space, does the coordinate projection $\pi :H\oplus H\rightarrow H$ take closed subspaces to closed subspaces?

asked Apr 6, 2015 at 5:27

4 votes

1 answer

559 views

Sheaf of sections vanishing at a point is $\Gamma(E) \otimes I_p$

asked Aug 20, 2014 at 5:02

4 votes

4 answers

537 views

An extension of line bundles splits locally

asked Jun 25, 2014 at 22:12

4 votes

4 answers

1k views

Is there a (f.g., free) module isomorphic to a quotient of itself?

asked Mar 11, 2014 at 22:36

4 votes

2 answers

132 views

If $(x_n)$ is a linear recurrence, is the same true for the subsequence $(x_{pn+q})$?

asked Feb 12, 2019 at 21:51

3 votes

1 answer

1k views

"Local free"ness in vector bundles and projective modules

asked May 29, 2014 at 18:31

3 votes

0 answers

59 views

If $G$ is a topological/algebraic group, is there a purely group-theoretic interpretation of $G^0$?

asked Nov 30, 2016 at 22:03

3 votes

1 answer

250 views

Ultralimit extends limit of nets?

asked Mar 19, 2020 at 15:31

2 votes

0 answers

91 views

Is ultrafilter convolution a special case of convolution of probability measures?

asked Mar 6, 2020 at 20:44

2 votes

0 answers

168 views

Hadamard quotient of D-finite series

asked Jun 5, 2019 at 22:37

2 votes

1 answer

145 views

Characterization of real intervals $[a,b]$ as posets

asked Aug 7, 2019 at 16:00

2 votes

1 answer

210 views

When are a set and its complement both syndetic?

asked Dec 27, 2019 at 20:04

2 votes

0 answers

74 views

Proof that a particular subgroup is proper

asked Dec 5, 2014 at 4:56

2 votes

1 answer

788 views

Every modular right ideal is contained in a modular maximal ideal

asked Jul 2, 2015 at 16:07

2 votes

1 answer

2k views

What's wrong with my proof that reductive Lie algebras are semisimple?

asked Apr 6, 2014 at 18:48

2 votes

0 answers

82 views

If $\mathbb{C}[G]$ is Noetherian and $G$ has a representation on $V$, when must $V$ be finite-dimensional?

asked Jul 25, 2013 at 15:09

2 votes

1 answer

228 views

Prove that $H^1(\mathcal{M}^*)=0$.

asked Jul 28, 2014 at 22:44

1 vote

1 answer

788 views

Countable set in a Banach space which spans densely?

asked May 24, 2015 at 23:12

Stack Exchange Network

37 Questions

Is there a group $G$ for which $\mathrm{Aut}(G) \simeq (\mathbb{R},+)$?

Examples of subgroups where it's nontrivial to show closure under multiplication?

Morita equivalent rings have homeomorphic spectra?

Prove that semi-simple rings are Dedekind-finite

Nontrivial examples of pro-$p$ groups

If $N$ and $G/N$ are virtually solvable, then $G$ is virtually solvable?

Inducing homomorphisms on localizations of rings/modules

Quotient of locally free sheaf is locally free?

Algebraic results using lower K-theory as a blackbox

Rank of projective module defined as the smallest $n$ such that $P$ is a direct summand of $R^n$

If the torsion subset of a group has "finite index", is the group torsion?

If $R$ is a simple ring, is every corner $eRe$ simple?

If $H$ is a Hilbert space, does the coordinate projection $\pi :H\oplus H\rightarrow H$ take closed subspaces to closed subspaces?

Sheaf of sections vanishing at a point is $\Gamma(E) \otimes I_p$

An extension of line bundles splits locally

Is there a (f.g., free) module isomorphic to a quotient of itself?

If $(x_n)$ is a linear recurrence, is the same true for the subsequence $(x_{pn+q})$?

"Local free"ness in vector bundles and projective modules

If $G$ is a topological/algebraic group, is there a purely group-theoretic interpretation of $G^0$?

Ultralimit extends limit of nets?

Is ultrafilter convolution a special case of convolution of probability measures?

Hadamard quotient of D-finite series

Characterization of real intervals $[a,b]$ as posets

When are a set and its complement both syndetic?

Proof that a particular subgroup is proper

Every modular right ideal is contained in a modular maximal ideal

What's wrong with my proof that reductive Lie algebras are semisimple?

If $\mathbb{C}[G]$ is Noetherian and $G$ has a representation on $V$, when must $V$ be finite-dimensional?

Prove that $H^1(\mathcal{M}^*)=0$.

Countable set in a Banach space which spans densely?