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arXiv 1705.00935math.AGmath.OAquant-ph
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关于Kippenhahn的一个定理

On a theorem by Kippenhahn

Stephan Weis

摘要:

Kippenhahn发现了一个真正的代数平面曲线,其凸包是一个矩阵的数值域。当钱和中里发现一个空间模拟失败的例子时,这个定理的正确性受到了质疑。他们表明,上述平面曲线确实位于数值域内。我们证明了定理的一个较容易的逆方向。寻找Kippenhahn定理的高维推广在实代数几何中是一个挑战。

英文摘要:

Kippenhahn discovered a real algebraic plane curve whose convex hull is the numerical range of a matrix. The correctness of this theorem was called into question when Chien and Nakazato found an example where the spatial analogue fails. They showed that the mentioned plane curve indeed lies inside the numerical range. We prove the easier converse direction of the theorem. Finding higher-dimensional generalizations of Kippenhahn's theorem is a challenge in real algebraic geometry.

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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