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arXiv 0906.1071math.CO
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拟阵的半平面性质与Tutte群

On the half-plane property and the Tutte group of a matroid

Petter Brändén, Rafael S. González D'León

摘要:

一个多元多项式是稳定的,如果它是非零的,只要所有变量都有正的虚部。一个拟阵具有弱半平面性质(WHPP),如果存在一个稳定的多项式,其支撑等于该拟阵的基集。如果多项式的所有非零系数都等于1,则拟阵具有半平面性质(HPP)。我们描述了一个系统的方法,使我们能够减少WHPP的HPP为大家庭的拟阵。这种方法利用了拟阵的Tutte群。证明了没有射影几何具有WHPP,二元拟阵具有WHPP当且仅当它是正则的。我们还证明了T_8和R_9不具有WHPP。

英文摘要:

A multivariate polynomial is stable if it is non-vanishing whenever all variables have positive imaginary parts. A matroid has the weak half-plane property (WHPP) if there exists a stable polynomial with support equal to the set of bases of the matroid. If the polynomial can be chosen with all of its nonzero coefficients equal to one then the matroid has the half-plane property (HPP). We describe a systematic method that allows us to reduce the WHPP to the HPP for large families of matroids. This method makes use of the Tutte group of a matroid. We prove that no projective geometry has the WHPP and that a binary matroid has the WHPP if and only if it is regular. We also prove that T_8 and R_9 fail to have the WHPP.

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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