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arXiv 1902.04231math.CVmath.CO
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如何计算多项式在单位圆上的零点个数?

How to count the number of zeros that a polynomial has on the unit circle?

R. S. Vieira

摘要:

计算实多项式的实零点个数的经典问题很久以前就由Sturm解决了。然而,计算多项式在单位圆上的零点个数的类似问题仍然是一个悬而未决的问题。在本文中,我们表明,第二个问题可以减少到第一个通过使用一个合适的莫比乌斯变换对-通常称为凯莱变换-具有映射的单位圆到实数线,反之亦然的属性。虽然该方法适用于任意复杂的多项式,我们详细讨论了几类多项式的对称零点,例如,自共轭,自伴,自反演,自互反和斜互反多项式的情况。最后讨论了该方法在Salem多项式和具有小Mahler测度的多项式中的应用。

英文摘要:

The classical problem of counting the number of real zeros of a real polynomial was solved a long time ago by Sturm. The analogous problem of counting the number of zeros that a polynomial has on the unit circle is, however, still an open problem. In this paper, we show that the second problem can be reduced to the first one through the use of a suitable pair of Möbius transformations - often called Cayley transformations - that have the property of mapping the unit circle onto the real line and vice versa. Although the method applies to arbitrary complex polynomials, we discuss in detail several classes of polynomials with symmetric zeros as, for instance, the cases of self-conjugate, self-adjoint, self-inversive, self-reciprocal and skew-reciprocal polynomials. Finally, an application of this method to Salem polynomials and to polynomials with small Mahler measure is also discussed.

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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