arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.06324math.AG
收藏

射影平面曲线补集之间的同构

Isomorphisms between complements of projective plane curves

Mattias Hemmig

AI总结:

本文研究射影平面不可约曲线补集间的同构,证明单尖点曲线补集同构蕴含射影等价,并推广至次数≤7的曲线,同时给出次数8的新反例。

摘要:

本文研究了在任意代数闭域上,射影平面 $\mathbb{P}^2$ 中不可约曲线的补集之间的同构。特别关注有理单尖点曲线。我们证明,如果存在一条直线仅与单尖点曲线 $C \subset \mathbb{P}^2$ 的奇异点相交,那么任何其补集与 $\mathbb{P}^2 \setminus C$ 同构的其他曲线必与 $C$ 射影等价。这推广了 H. Yoshihara 在复数域上证明的结果。此外,我们研究了不可约曲线的重数序列的性质,这些性质蕴含这些曲线的补集之间的任何同构都能延拓为 $\mathbb{P}^2$ 的自同构。利用这些结果,我们证明两条次数 $\leq 7$ 的不可约曲线具有同构的补集当且仅当它们射影等价。最后,我们描述了次数为 $8$ 的不可约射影非等价曲线的新例子,这些曲线具有同构的补集。

英文摘要:

In this article, we study isomorphisms between complements of irreducible curves in the projective plane $\mathbb{P}^2$, over an arbitrary algebraically closed field. Of particular interest are rational unicuspidal curves. We prove that if there exists a line that intersects a unicuspidal curve $C \subset \mathbb{P}^2$ only in its singular point, then any other curve whose complement is isomorphic to $\mathbb{P}^2 \setminus C$ must be projectively equivalent to $C$. This generalizes a result of H. Yoshihara who proved this result over the complex numbers. Moreover, we study properties of multiplicity sequences of irreducible curves that imply that any isomorphism between the complements of these curves extends to an automorphism of $\mathbb{P}^2$. Using these results, we show that two irreducible curves of degree $\leq 7$ have isomorphic complements if and only if they are projectively equivalent. Finally, we describe new examples of irreducible projectively non-equivalent curves of degree $8$ that have isomorphic complements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑