User Angelo

12 votes

Extending vector bundles on a given open subscheme

answered Apr 21, 2010 at 20:48

12 votes

Curve minus point isomorphic to Curve?

answered May 20, 2010 at 8:51

12 votes

Accepted

A characteristic-free proof that the action of a connected algebraic group $G$ on the fundamental group of a $G$-variety is trivial

answered Feb 28, 2011 at 15:55

12 votes

Accepted

When is a sheaf on a scheme extendable to a representable functor?

answered Jun 18, 2011 at 2:57

12 votes

Accepted

n-th integral cohomology of a non-compact manifold of dimension n

answered Jul 18, 2011 at 8:29

12 votes

Accepted

Is there a ``path'' between any two fiber functors over the same field in Tannakian formalism?

answered Jul 31, 2011 at 16:36

12 votes

Accepted

Is every (Artin/DM) algebraic stack fibered in sets an algebraic space?

answered Oct 11, 2010 at 21:02

11 votes

The single-plus construction is not the left adjoint of the inclusion of separated presheaves?

answered Dec 15, 2010 at 7:20

11 votes

Accepted

Are representations of a linearly reductive group discretely parameterized?

answered Feb 21, 2011 at 10:03

11 votes

Accepted

Natural embedding GL_n(C) -> C^{n^2} \ {0} induces zero on cohomology

answered Apr 29, 2010 at 14:52

11 votes

How to correct an error in a submitted paper?

answered Apr 21, 2010 at 15:55

11 votes

Accepted

$K_{0}(R) =\mathbb{Z}$ but some f.g. projective not stably free?

answered Jun 10, 2010 at 5:17

11 votes

Accepted

Nonnegative additive functions on coherent sheaves

answered Dec 13, 2011 at 9:22

11 votes

Accepted

How does descent theory imply a sheaf is a scheme?

answered Nov 21, 2012 at 8:00

10 votes

Why can I divide an affine variety by the action of the general linear group?

answered Apr 17, 2012 at 16:50

10 votes

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Moduli Space of Abelian Varieties with a N-torsion point

answered Jun 27, 2012 at 14:56

10 votes

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Is the support of a flat sheaf flat?

answered Feb 10, 2012 at 21:53

10 votes

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Quotient of algebraic groups in the étale topology

answered Jun 12, 2013 at 2:35

10 votes

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Subgroups of algebraic groups

answered Jun 12, 2013 at 18:32

10 votes

Are root stacks characterized by their divisor multiplicities?

answered Sep 7, 2010 at 19:21

10 votes

Accepted

Semiring of algebraic vector bundles on projective space

answered Apr 6, 2010 at 3:33

10 votes

Accepted

Proving existence of non-special divisors of a given degree d on compact Riemann surfaces

answered Apr 19, 2010 at 5:51

10 votes

Cartier divisor on an open subscheme whose complement is of codim 2

answered Mar 28, 2010 at 15:12

10 votes

Accepted

Fixed points of the action of an algebraic group

answered Apr 5, 2011 at 9:52

10 votes

Accepted

Does there exist a non-trivial semi-stable curve of genus >1 with only 4 singular fibres

answered May 6, 2011 at 13:22

10 votes

Accepted

Query on comment in Deligne-Mumford (1969)

answered Aug 18, 2011 at 4:19

10 votes

Accepted

Branched covers of compact Riemann surfaces

answered Jul 10, 2011 at 9:40

10 votes

Nonfree projective module over a regular UFD?

answered Feb 4, 2011 at 21:48

9 votes

Proposition 3.93 of Harris-Morrison (rational classes on Deligne-Mumford moduli stack vs. rational classes on Deligne-Mumford moduli space)

answered Feb 15, 2011 at 6:14

9 votes

Accepted

Does unramified + radicial imply that a morphism is an immersion?

answered Jan 19, 2011 at 13:24

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266 Answers

Extending vector bundles on a given open subscheme

Curve minus point isomorphic to Curve?

A characteristic-free proof that the action of a connected algebraic group $G$ on the fundamental group of a $G$-variety is trivial

When is a sheaf on a scheme extendable to a representable functor?

n-th integral cohomology of a non-compact manifold of dimension n

Is there a ``path'' between any two fiber functors over the same field in Tannakian formalism?

Is every (Artin/DM) algebraic stack fibered in sets an algebraic space?

The single-plus construction is not the left adjoint of the inclusion of separated presheaves?

Are representations of a linearly reductive group discretely parameterized?

Natural embedding GL_n(C) -> C^{n^2} \ {0} induces zero on cohomology

How to correct an error in a submitted paper?

$K_{0}(R) =\mathbb{Z}$ but some f.g. projective not stably free?

Nonnegative additive functions on coherent sheaves

How does descent theory imply a sheaf is a scheme?

Why can I divide an affine variety by the action of the general linear group?

Moduli Space of Abelian Varieties with a N-torsion point

Is the support of a flat sheaf flat?

Quotient of algebraic groups in the étale topology

Subgroups of algebraic groups

Are root stacks characterized by their divisor multiplicities?

Semiring of algebraic vector bundles on projective space

Proving existence of non-special divisors of a given degree d on compact Riemann surfaces

Cartier divisor on an open subscheme whose complement is of codim 2

Fixed points of the action of an algebraic group

Does there exist a non-trivial semi-stable curve of genus >1 with only 4 singular fibres

Query on comment in Deligne-Mumford (1969)

Branched covers of compact Riemann surfaces

Nonfree projective module over a regular UFD?

Proposition 3.93 of Harris-Morrison (rational classes on Deligne-Mumford moduli stack vs. rational classes on Deligne-Mumford moduli space)

Does unramified + radicial imply that a morphism is an immersion?