arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1306.1445math.AG
收藏

Wachspress表面的几何形状

Geometry of Wachspress surfaces

Corey Irving, Hal Schenck

摘要:

设P_d是具有d个顶点的凸多边形。Wachspress曲面W_d是逼近论中的一个基本对象,它定义为从P^2到P^{d-1}的有理映射w_d的像,由P_d的Wachspress重心坐标确定。我们证明了w_d是P^2的爆破X_d上的正则映射,并且如果d>4由X_d上的一个非常充分的因子给出,则光滑像W_d也是如此.确定了W_d的理想的生成元,证明了在分次lex序下,I(W_d)的初始理想由Stanley-Reisner理想给出.由此证明了相应的曲面是具有Castelnuovo-Mumford正则性2的算术Cohen-Macaulay曲面,并确定了I(W_d)的所有分次贝蒂数.

英文摘要:

Let P_d be a convex polygon with d vertices. The associated Wachspress surface W_d is a fundamental object in approximation theory, defined as the image of the rational map w_d from P^2 to P^{d-1}, determined by the Wachspress barycentric coordinates for P_d. We show w_d is a regular map on a blowup X_d of P^2, and if d>4 is given by a very ample divisor on X_d, so has a smooth image W_d. We determine generators for the ideal of W_d, and prove that in graded lex order, the initial ideal of I(W_d) is given by a Stanley-Reisner ideal. As a consequence, we show that the associated surface is arithmetically Cohen-Macaulay, of Castelnuovo-Mumford regularity two, and determine all the graded betti numbers of I(W_d).

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。

↑