AI 中文总结
该研究证明了平面上的彩色体积Helly定理,给出相关常数V的存在性,并以凸四边形半平面交的测度估计为核心依据,得出对应测度上界结论。
AI 中文摘要
我们证明了R²中凸集的彩色体积Helly定理:存在常数V>0,若𝔽₁、𝔽₂、𝔽₃、𝔽₄是R²中凸集的有限族,且对每个横截集F_i∈𝔽_i(i=1,…,4),都有|∩₁⁴F_i|≥V,则存在某个i使得|∩𝔽_i|≥1。此处|A|表示R^d中集合A的Lebesgue测度。主要依据的定理为:设Q₁,…,Q₄是R²中面积不超过1的凸四边形(每个Q_i自然是4个半平面的交),则对每个Q_i,都存在其中一个半平面H_i,使得|∩₁⁴H_i|≤4096。
英文摘要
We prove a colorful volume Helly theorem for convex sets in $\mathbb R^2$: There is a constant $V>0$ such that if $\mathfrak F_1,\mathfrak F_2,\mathfrak F_3,\mathfrak F_4$ are finite families of convex sets in $\mathbb R^2$ and if $|\bigcap_1^4F_i|\ge V$ for every transversal $F_i\in \mathfrak F_i,\; (i=1,\ldots,4)$, then $|\bigcap \mathfrak{F}_i|\ge 1$ for some $i$. Here $|A|$ is the Lebesgue measure of $A\subset \mathbb R^d$. The main ingredient is the following theorem. Let $Q_1,\ldots,Q_4\subset\mathbb R^2$ be convex quadrilaterals of area at most $1$, where of course each $Q_i$ is the intersection of 4 halfplanes. Then for every $Q_i$ there is one of these halfplanes $H_i$, say, such that $|\bigcap_1^4 H_i| \le 4096$.