User Bernie

6 votes

1 answer

250 views

Are there curves of genus 2 with real multiplication by a non-maximal order?

asked Aug 28, 2017 at 13:41

5 votes

1 answer

278 views

Are there primitive quartic CM fields whose norms of units give all totally positive units of the real quadratic subfield?

asked Jun 28, 2017 at 13:34

4 votes

0 answers

495 views

Is the Gysin map in etale cohomology compatible with taking function fields?

asked Aug 8, 2017 at 11:45

4 votes

0 answers

198 views

Can Kummer surfaces coming from the same abelian surface be Cremona equivalent / isomorphic?

asked Sep 21, 2017 at 13:47

4 votes

1 answer

235 views

Existence of regular conic bundles with a given discriminant divisor

asked Mar 16, 2017 at 14:10

4 votes

0 answers

335 views

Modules over an Azumaya algebra and modules over the associated Brauer-Severi variety

asked Sep 4, 2015 at 12:01

4 votes

1 answer

255 views

Can relative flatness of a sheaf be tested using (faithfully) flat morphisms?

asked Sep 28, 2015 at 15:12

4 votes

1 answer

311 views

Relative tangent bundle of a twisted Grassmann variety

asked Aug 9, 2016 at 14:36

3 votes

0 answers

269 views

Can one construct the GIT quotient of a projective bundle?

asked Sep 10, 2016 at 16:04

3 votes

2 answers

371 views

Is this quotient of a threefold known? What are its singularities?

asked Oct 3, 2016 at 17:24

3 votes

1 answer

376 views

What is known about the cohomology of the relative tangent bundle on a conic bundle?

asked Feb 25, 2016 at 17:01

3 votes

0 answers

144 views

Which blow ups in the base of a conic bundle preserve the "standard" condition?

asked Jul 19, 2016 at 15:01

3 votes

0 answers

335 views

Which sheaves on a projective bundle are flat over the base scheme?

asked Oct 5, 2015 at 10:03

3 votes

0 answers

272 views

Can one control the ramification of a Brauer class under birational morphisms?

asked Nov 16, 2015 at 17:53

3 votes

0 answers

287 views

How much information is encoded in the Jacobian-Kummer K3 surface of a curve of genus two?

asked Jun 8, 2017 at 10:08

3 votes

1 answer

101 views

Why does the variety of ideals in this quaternion type algebra have a non-reduced structure?

asked Nov 4, 2016 at 14:21

3 votes

0 answers

158 views

Moduli space with exceptional Mukai vector and tangent spaces at strictly semistable bundles

asked Jul 8, 2022 at 10:54

2 votes

1 answer

225 views

What finite groups are stabilizers in Kirwan's desingularization construction?

asked Feb 1, 2016 at 18:00

2 votes

2 answers

607 views

Canonical (tautological) section of a family of sheaves

asked May 12, 2015 at 16:08

2 votes

0 answers

231 views

Surjectivity locus of a morphism of families of sheaves

asked Jun 24, 2015 at 12:19

2 votes

0 answers

74 views

If a subgroup H of a finite group G acts freely on a variety, can the G-Hilbert scheme be computed by iteration?

asked Oct 17, 2016 at 14:02

1 vote

0 answers

166 views

Are two conic bundles birational, if their bases are birational via a map preserving the associated quaternion algebras?

asked Jul 6, 2016 at 13:29

1 vote

1 answer

506 views

Can one drop the locally free assumption in projection formula on a projective bundle?

asked Oct 7, 2015 at 16:39

1 vote

1 answer

256 views

About the canonical morphism from $f^{}f_{}f^{}F$ to $f^{}F$

asked Oct 12, 2015 at 17:40

1 vote

1 answer

177 views

How to test if these two threefolds are birationally equivalent?

asked Nov 14, 2016 at 22:05

0 votes

0 answers

81 views

A quaternion x generates a left ideal of rank 2 if and only if x, ix and jx are linearly dependent?

asked Jan 13, 2017 at 14:36

0 votes

1 answer

151 views

Behaviour of (principal) polarizations of (singular) surfaces under birational maps

asked Oct 20, 2017 at 13:52

0 votes

1 answer

110 views

How to find ideals of finite length in a power series ring with special properties?

asked Jun 16, 2015 at 14:04

Stack Exchange Network

28 Questions

Are there curves of genus 2 with real multiplication by a non-maximal order?

Are there primitive quartic CM fields whose norms of units give all totally positive units of the real quadratic subfield?

Is the Gysin map in etale cohomology compatible with taking function fields?

Can Kummer surfaces coming from the same abelian surface be Cremona equivalent / isomorphic?

Existence of regular conic bundles with a given discriminant divisor

Modules over an Azumaya algebra and modules over the associated Brauer-Severi variety

Can relative flatness of a sheaf be tested using (faithfully) flat morphisms?

Relative tangent bundle of a twisted Grassmann variety

Can one construct the GIT quotient of a projective bundle?

Is this quotient of a threefold known? What are its singularities?

What is known about the cohomology of the relative tangent bundle on a conic bundle?

Which blow ups in the base of a conic bundle preserve the "standard" condition?

Which sheaves on a projective bundle are flat over the base scheme?

Can one control the ramification of a Brauer class under birational morphisms?

How much information is encoded in the Jacobian-Kummer K3 surface of a curve of genus two?

Why does the variety of ideals in this quaternion type algebra have a non-reduced structure?

Moduli space with exceptional Mukai vector and tangent spaces at strictly semistable bundles

What finite groups are stabilizers in Kirwan's desingularization construction?

Canonical (tautological) section of a family of sheaves

Surjectivity locus of a morphism of families of sheaves

If a subgroup H of a finite group G acts freely on a variety, can the G-Hilbert scheme be computed by iteration?

Are two conic bundles birational, if their bases are birational via a map preserving the associated quaternion algebras?

Can one drop the locally free assumption in projection formula on a projective bundle?

About the canonical morphism from $f^{}f_{}f^{}F$ to $f^{}F$

How to test if these two threefolds are birationally equivalent?

A quaternion x generates a left ideal of rank 2 if and only if x, ix and jx are linearly dependent?

Behaviour of (principal) polarizations of (singular) surfaces under birational maps

How to find ideals of finite length in a power series ring with special properties?