Three polynomials are defined for given sets $S$ of $n$ points in general position in the plane: The Voronoi polynomial with coefficients the numbers of vertices of the order-$k$ Voronoi diagrams of $S$, the circle polynomial with coefficients the numbers of circles through three points of $S$ enclosing $k$ points of $S$, and the $E_{\leq k}$ polynomial with coefficients the numbers of (at most $k$)-edges of $S$. We present several formulas for the rectilinear crossing number of $S$ in terms of these polynomials and their roots. We also prove that the roots of the Voronoi polynomial lie on the unit circle if, and only if, $S$ is in convex position. Further, we present bounds on the location of the roots of these polynomials.
翻译:针对平面中处于一般位置的 $n$ 个点集 $S$,本文定义了三种多项式:沃罗诺伊多项式(系数为 $S$ 的 $k$ 阶沃罗诺伊图的顶点数)、圆多项式(系数为过 $S$ 中三个点且包含 $S$ 中 $k$ 个点的圆的数量),以及 $E_{\leq k}$ 多项式(系数为 $S$ 中至多 $k$ 条边的数量)。我们给出了 $S$ 的直线交叉数关于这些多项式及其根的若干公式,并证明沃罗诺伊多项式的根位于单位圆上当且仅当 $S$ 处于凸位置。此外,我们还给出了这些多项式根的位置边界。