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Questions tagged [fano-varieties]

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11 votes
0 answers
684 views

Big tangent bundle

Let $X$ be a nonsingular complex algebraic variety whose tangent bundle is $T_X$. I use Lazarsfeld's book for the definition of a big vector bundle. A line bundle $L$ is big if it has Itaka dimension ...
7 votes
1 answer
609 views

Is there an Enriques–Kodaira-like classification of Fano threefolds?

I am mainly interested in varieties over an algebraic closed field $k$ (or $\mathbb{C}$). The classification of complex surface is established in the last century and known as Enriques–Kodaira ...
15 votes
2 answers
1k views

How does one prove that the complete intersection of a quadric and a cubic of $\mathbb P^5$ is unirational?

The question is stated in the title, but I would like to add some motivation. I've been teaching a course on complex tori and abelian varieties this semester and I would like to end it by showing ...
14 votes
1 answer
1k views

Frobenius splitting of Fano varieties

Dear MO, Question 1. Do you know of an example of a Fano variety which is not Frobenius split? Background (1) A variety $X$ in characteristic $p$ is called Frobenius split if there is a "$p$-th ...
3 votes
1 answer
609 views

Semiorthogonal decompositions for Fano 3-folds and 4folds

Let $X$ be a projective Fano 3-fold or 4-fold and let $D^b(X)$ be the bounded derived category of coherent sheaves on $X$. For what $X$ is it known a semi orthogonal decomposition into indecomposable ...
6 votes
0 answers
378 views

Bound for the Picard number of a Fano 3-fold

Let $X$ be a Fano 3-fold with terminal singularities. Is there some bound (possibly explicit) for the Picard rank of $X$ ? If $X$ is smooth, it is well-known that the bound is $10$, obtained by del ...

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