Components of the Hilbert scheme of smooth projective curves using ruled surfaces

Autor: Seonja Kim, Hristo Iliev, Youngook Choi
Rok vydání: 2020
Předmět:
Zdroj: manuscripta mathematica. 164:395-408
ISSN: 1432-1785
0025-2611
Popis: Let $${\mathcal {I}}_{d,g,r}$$ be the union of irreducible components of the Hilbert scheme whose general points correspond to smooth irreducible non-degenerate curves of degree d and genus g in $$\mathbb {P}^r$$ . We use families of curves on cones to show that under certain numerical assumptions for d, g and r, the scheme $${\mathcal {I}}_{d,g,r}$$ acquires generically smooth components whose general points correspond to curves that are double covers of irrational curves. In particular, in the case $$\rho (d,g,r) := g-(r+1)(g-d+r) \ge 0$$ we construct explicitly a regular component that is different from the distinguished component of $${\mathcal {I}}_{d,g,r}$$ dominating the moduli space $${\mathcal {M}}_g$$ . Our result implies also that if $$g \ge 57$$ then $${\mathcal {I}}_{\frac{4g}{3}, g, \frac{g+1}{2}}$$ has at least two generically smooth components parametrizing linearly normal curves.
Databáze: OpenAIRE