On projective curves of next to maximal regularity

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• 作者：Wanseok Lee
• 关键词：14N05 ; 14H45
• 刊名：Journal of Pure and Applied Algebra
• 出版年：April, 2014
• 年：2014
• 卷：218
• 期：4
• 页码：735-742
• 全文大小：397 K

文摘

It is known that if a rational curve () of degree fails to be -regular then admits a unique -secant line and the arithmetic genus of is at most . In this paper, we study the effect of such a secant line on algebraic and geometric properties of the curve . We show that if the singular locus of does not lie on then is obtained by a simple linear projection of a curve of maximal regularity. Also we show that if then is -regular which enables us to estimate the Hartshorne-Rao module and the graded Betti numbers of .