Let $X$ be a curve in the projective 3-space, formed by a disjoint union of complete intersection curves of the same ``type'' $(r,s)$. Then $X$ is subcanonical, i.e. $\omega_X=\scr O_X(r+s-4)$, so it is the 0-locus of a section of a rank 2 vector bundle $E$. The authors show here that, numerically, bundles arising from disjoint union of complete intersection curves are characterized by the dimensions of the first cohomology groups: if $F$ is any vector bundle with $c_1(F)=c_1(E)$ and $h^1F(n)=h^1E(n)$ for all $n$, then $F$ has a section whose 0-locus $X'$ has the same numerical characters (degree, genus, postulation, etc.) as $X$.
Subcanonical curves with the same postulation as $Q$ skew complete intersections in projective $3$-space
ROGGERO, Margherita;
1989-01-01
Abstract
Let $X$ be a curve in the projective 3-space, formed by a disjoint union of complete intersection curves of the same ``type'' $(r,s)$. Then $X$ is subcanonical, i.e. $\omega_X=\scr O_X(r+s-4)$, so it is the 0-locus of a section of a rank 2 vector bundle $E$. The authors show here that, numerically, bundles arising from disjoint union of complete intersection curves are characterized by the dimensions of the first cohomology groups: if $F$ is any vector bundle with $c_1(F)=c_1(E)$ and $h^1F(n)=h^1E(n)$ for all $n$, then $F$ has a section whose 0-locus $X'$ has the same numerical characters (degree, genus, postulation, etc.) as $X$.File in questo prodotto:
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