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arXiv 2602.02144math.GT
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优化多项式曲线系统交叉数上界常数

Optimizing the Upper-Bound Constant for the Crossing Number of Polynomial Curve Systems

Hyungryul Baik

AI总结:

本文优化了多项式曲线系统交叉数上界常数,通过放松参数对称性并解决熵平衡问题,将上界常数降低约30%。

摘要:

Baader, Jörg,和Parlier最近为 genus g 表面上大小为 m≈g^{1+α} 的曲线系统建立了上界,得到了一个主导系数为 9/4=2.25。他们的构造依赖于与完全二分图相关的纤维表面,并使用对称参数选择对应于中心二项式系数。在本笔记中,我们通过放松参数对称性并解决由此产生的熵平衡问题来优化其构造。我们证明,对于每个 α>0 和每个 ε>0,$$ \mathrm{Cr}\bigl(g,\lfloor g^{1+α}\rfloor\bigr) \ \le\ (C_\star+\varepsilon)\,α^2\, g^{1+2α}(\log g)^2 \qquad (g\ \text{sufficiently large}), $$ 其中 $$ C_\star\ =\ \inf_{0<x\le 1/2}\ \frac{2x}{H(x)^2} \ \approx\ 1.5805443269, \qquad H(x)=-x\log x-(1-x)\log(1-x). $$ 这将之前的常数减少了约 30%,同时仍保持在相同的拓扑框架内。

英文摘要:

Baader, Jörg, and Parlier recently established an upper bound for the crossing number of curve systems of size $m\asymp g^{1+α}$ on a genus $g$ surface, obtaining a leading coefficient of $9/4=2.25$. Their construction relies on fibre surfaces associated with complete bipartite graphs and uses a symmetric parameter choice corresponding to the central binomial coefficient. In this note, we optimize their construction by relaxing the parameter symmetry and solving the resulting entropy balance problem. We show that for every $α>0$ and every $\varepsilon>0$, \[ \mathrm{Cr}\bigl(g,\lfloor g^{1+α}\rfloor\bigr) \ \le\ (C_\star+\varepsilon)\,α^2\, g^{1+2α}(\log g)^2 \qquad (g\ \text{sufficiently large}), \] where \[ C_\star\ =\ \inf_{0<x\le 1/2}\ \frac{2x}{H(x)^2} \ \approx\ 1.5805443269, \qquad H(x)=-x\log x-(1-x)\log(1-x). \] This reduces the previous constant by about $30\%$ while staying within the same topological framework.

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。

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