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6 votes
0 answers
674 views

Bezout Theorem in $\mathbb P^3$

For a $\mathbb C P^2$ is known a result: if through the generic points $p_1,p_2,\dots p_n$ with multiplicities $m_1,m_2\dots, m_n$ correspondingly a degree $d$ curve passes then $d^2\geq m_1^2+m_2^2+\...
Nikita Kalinin's user avatar
5 votes
0 answers
326 views

Max Noether's theorem for algebraic surfaces

The well-known Max Noether's theorem for curves [see Arbarello-Cornalba-Griffiths-Harris Geometry of Algebraic Curves vol.1, p. 117] states that, if a smooth curve $C$ is non-hyperelliptic, then the ...
Francesco Polizzi's user avatar
3 votes
0 answers
287 views

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

Assume we work over $\mathbb{C}$. Let $S\subset \mathbb{P}^3$ be a quartic surfaces with 16 nodes (ordinary double points). Then there is a simple principally polarized abelian surface $(A,\theta)$ ...
Bernie's user avatar
  • 1,025
3 votes
0 answers
255 views

Intuition behind results in Mumford's “Lectures on curves on an algebraic surface”, II

NOTE: This is a followup to my question here. These are some questions concerning Mumford's "Lectures on curves on an algebraic surface". We concern ourselves with questions of the Picard variety $P$...
user avatar
3 votes
0 answers
298 views

What does Hodge theory tell us about simply connected surfaces of general type

Let $X$ be a smooth complex projective variety. We know that $\Omega^1_X$ has a non-zero section if and only if the abelianization of the fundamental group of X is infinite. This follows from Hodge ...
Fabiano Rug's user avatar
2 votes
0 answers
65 views

What conditions are sufficient for two points to be independent in the Mordell-Weil group?

Consider a finite field $\mathbb{F}_{q}$ and an elliptic surface $$ \mathcal{E}\!: y^2 + a_1(t)xy + a_3(t)y = x^3 + a_2(t)x^2 + a_4(t)x + a_6(t), $$ where $a_i(t) \in \mathbb{F}_{q}[t]$. I am mainly ...
Dimitri Koshelev's user avatar
2 votes
0 answers
137 views

Is a supersingular Kummer surface $k$-unirational in characteristic 2?

Let $k$ be a perfect field of even characteristic. Consider the simplest example of a supersingular genus 2 curve, i.e., $$ C\!: y^2 + y = x^5. $$ By the article of J. S. Müller "Explicit Kummer ...
Dimitri Koshelev's user avatar
2 votes
0 answers
289 views

quasi-trigonal curves

I have read in the literature about quasi-trigonal curves. Such a curve C is a hyperelliptic curve X with two points p,q identified (basically a pinch). They seem to be pretty important in the theory ...
IMeasy's user avatar
  • 3,779
1 vote
0 answers
262 views

Section ring $R(X,D)$ of $D$ is finitely generated if $\kappa (X,D) \leq 1$

In the remark on the bottom of page 5 of this paper, the author states that It is well-known fact that the algebra of a Divisor $D$ with $\kappa (X,D) \leq 1$ is finitely generated over $k$. In ...
numberjedi's user avatar
0 votes
0 answers
51 views

Does this tangent developable-like surface have a cusp along a curve or is it smooth?

Consider the following surface $X$ which is a subvariety of the full flag variety $Y=\{0 \subset V_1 \subset V_2 \subset V\}$ where $V$ is a fixed three-dimensional vector space and ${\rm dim} V_i =i$....
Yellow Pig's user avatar
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