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Understanding the Hilbert scheme of subvarieties of $\mathbb{CP}^n$

EDIT: migrated to MSE. I am looking to get a more concrete understanding of the Hilbert scheme of projective subvarieties, specifically over $\mathbb{C}$, and to obtain good references on this subject....
Paul Cusson's user avatar
  • 1,763
4 votes
1 answer
154 views

irreducibility punctual Hilbert scheme of relative subschemes of length $2$

Let $X$ be an irreducible projective variety over $\mathbb{C}$ (note that I do not assume $X$ smooth) and let $ p : X \longrightarrow S$ be a projective surjective morphism. For any open $U \subset S$,...
Libli's user avatar
  • 7,300
7 votes
0 answers
566 views

Philosophical underpinnings of Grothendieck's construction of the Hilbert scheme

Long ago when I was in grad school I was told that Grothendieck's construction of the Hilbert scheme is rooted in two main technical points: Castelnuovo-Mumford regularity and Mumford flattening ...
Yellow Pig's user avatar
  • 2,964
1 vote
0 answers
164 views

References for Hilbert schemes over non-Archimedean valuation

Can you suggest me some suitable references to learn the theory of Hilbert polynomials (or related Hilbert schemes) in the non-Archimedean setting? Thanks.
Sam Taylor's user avatar
2 votes
1 answer
240 views

Regarding a conjecture Fogarty proposed

In a paper by Fogarty titled "Algebraic Family On An Algebraic Surface," he conjectured that $\bf Hilb^n(\mathbb P^N)$ is always variety-- reduced and irreducible. Is this still a conjecture; any ...
Algeometry's user avatar
16 votes
1 answer
1k views

Reference Request for Hilbert Schemes

I'm a physicist working on Fractional Quantum Hall effect. The mathematical subjects of study are symmetric, translational invariant, homogeneous polynomials on $\mathbb{C}$. Very early in my study I ...
Hamed's user avatar
  • 613
3 votes
1 answer
451 views

Standard techniques on rationally connected varieties

Is there some standard technique or approach to determine when a (irreducible) subvariety of a rationally connected variety is again rationally connected? Any reference/text dealing with this kind of ...
Ron's user avatar
  • 2,126
3 votes
0 answers
205 views

Projective schemes with a fixed hyperplane section

Let $H$ be a hyperplane in $\mathbb P^n$, and $X \subseteq H$ be a subscheme. Let $CX \subseteq \mathbb P^n$ be the cone on $X$ from a point $p \notin H$. Let $Hilb_{CX}$ be the Hilbert scheme whose ...
Allen Knutson's user avatar
2 votes
0 answers
434 views

Is the universal closed subscheme reduced?

Let $G$ be a finite subgroup of $\text{SL}(2,\mathbb{C})$ and let $Y=\text{GHilb}(\mathbb{C}^2)$ be the minimal resolution of $X=\mathbb{C}^2/G$ where $\text{GHilb}(\mathbb{C}^2)$ is the Nakamura $G$-...
Ehsan M. Kermani's user avatar
5 votes
0 answers
325 views

"Reductive Groups and Hilbert Schemes" - Reference

Bezrukavnikov and Ginzburg have unpublished notes, 'Hilbert Schemes and Reductive Groups' (referenced here, for example): does anyone know what became of these notes? Did Bezrukavnikov-Ginzburg ...
George Melvin's user avatar
13 votes
3 answers
1k views

Reference for combinatorics of cell decomposition of the Hilbert scheme of points in the plane

It is known from either Morse theory or Bialynicki-Birula decomposition that the fixed points of a ${\mathbb{C}}^*$ action on a smooth algebraic variety over $\mathbb{C}$ determine a cell ...
Yellow Pig's user avatar
  • 2,964
9 votes
3 answers
2k views

Reference request: is the punctual Hilbert scheme irreducible?

The punctual Hilbert scheme in dimension $d$ parameterizes ideals $I$ of codimension $n$ in $k[x_1,\dots, x_d]$ which are contained in some power of the ideal $(x_1,\dots, x_d)$. In other words, it is ...
Anton Geraschenko's user avatar