2007 / March Volume 2 No.1
Pencils on coverings of a given curve whose degree is larger than the Castelnuovo-Severi lower bound
Published Date |
2007 / March
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Title | Pencils on coverings of a given curve whose degree is larger than the Castelnuovo-Severi lower bound |
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Pagination | 103-107 |
Abstract | Fix integers $q, g, k, d$. Set
$\pi_{d,k,q} := kd - d - k + kq + 1$
and assume
$q>0,\ k \ge 2,\ d \ge 3q + 1,\ g \ge kq - k + 1$
and
$\pi_{d,k,q} - ((\lfloor d/2 \rfloor + 1 - q) \cdot (\lfloor k/2 \rfloor + 1) \le g \le \pi_{d,k,q}$.
Let $Y$ be a smooth and connected genus $q$ projective curve. Here we prove the existence of a smooth and connected genus $g$ projective curve $X$, a degree $k$ morphism $f: X \to Y$ and a degree $d$ morphism $u: X \to P^1$ such that the morphism $(f, u): X \to Y \times P^1$ is birational onto its image. |
AMS Subject Classification |
14H51, 14H30
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Received |
2006-03-31
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