Skip to main content
minor grammar fixes
Source Link
Charles Staats
  • 7.3k
  • 5
  • 67
  • 86

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criterionscriteria about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

ifIf one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ reflexive sheaves, then one knows of course that each $V_i$ is reflexive. But is also the union of all these sheaves also reflexive?

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criterions about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

if one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ reflexive sheaves, then one knows of course that each $V_i$ is reflexive. But is also the union of all these sheaves reflexive?

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criteria about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

If one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ reflexive sheaves, then one knows of course that each $V_i$ is reflexive. But is the union of all these sheaves also reflexive?

deleted 37 characters in body
Source Link
Veen
  • 659
  • 4
  • 16

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criterions about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

if one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ of vector bundles (each of finite rank)reflexive sheaves, then one knows of course that each $V_i$ is reflexive. But is also the union of all these sheaves (direct limit) reflexive?

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criterions about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

if one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ of vector bundles (each of finite rank), then one knows of course that each $V_i$ is reflexive. But is also the union of all these sheaves (direct limit) reflexive?

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criterions about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

if one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ reflexive sheaves, then one knows of course that each $V_i$ is reflexive. But is also the union of all these sheaves reflexive?

Source Link
Veen
  • 659
  • 4
  • 16

Criterions for Reflexiveness of sheaves and a special case

A coherent sheaf $V$ on a say noetherian scheme is called reflexive if the canonical map $V \rightarrow \mathcal Hom_{\mathcal O_X}(\mathcal Hom_{\mathcal O_X}(V,\mathcal O_X),\mathcal O_X)$ is an isomorphism of sheaves.

In principle, one can define this notion also for quasicoherent sheaves, and this is what my question is about: does one have criterions about when a quasicoherent module is reflexive? Or is the question of reflexiveness in general very hard to answer?

What I am particularly interested in as a special case:

if one has an infinite chain of inclusions $V_1 \subset V_2 \subset ...$ of vector bundles (each of finite rank), then one knows of course that each $V_i$ is reflexive. But is also the union of all these sheaves (direct limit) reflexive?