منابع مشابه
Eneström-Kakeya Theorem and Some of Its Generalizations
The study of the zeros of polynomials has a very rich history. In addition to having numerous applications, this study has been the inspiration for much theoretical research (including being the initial motivation for modern algebra). The earliest contributors to this subject were Gauss and Cauchy. Algebraic and analytic methods for finding zeros of a polynomial, in general, can be quite compli...
متن کاملAn EnestrÖm-Kakeya Theorem for Hermitian Polynomial Matrices
We extend the Eneström-Kakeya theorem and its refinement by Hurwitz to polynomial matrices H(z) with positive semidefinite coefficients. We determine an annular region containing the zeros of detH(z). A stability result for systems of linear difference equations is given as an application.
متن کاملOn a Kakeya-type Problem
Let A be a finite subset of an abelian group G . For every element bi of the sumset 2A={b0, b1, ..., b|2A|−1} we denote by Di={a − a′ : a, a′∈A; a+a′=bi} and ri=|{(a, a′) : a+a′=bi; a, a′∈A}| . After an eventual reordering of 2A , we may assume that r0>r1>...>r|2A|−1. For every 16s6|2A| we define Rs(A) = |D0∪D1∪...∪Ds−1| and Rs(k)= max{Rs(A) : A⊆G, |A|=k}. Bourgain and Katz and Tao obtained an ...
متن کاملOn Some Variants of the Kakeya Problem
Besicovitch and Rado [1] and Kinney [5] proved the following result: There is a closed set E ⊂ R2 with measure zero which contains a circle of every radius. The construction of Besicovitch and Rado works in Rd: If d ≥ 3 there is a closed set E ⊂ Rd with measure zero which contains a sphere of every radius. We will give an exposition of this construction in Section 1 below. One can ask whether a...
متن کاملA Note on the Kakeya Maximal Operator
In this paper we obtain an upper bound for the L2 norm for maximal operators associated to arbitrary finite sets of directions in R 2.
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ژورنال
عنوان ژورنال: Applied Mathematics
سال: 2010
ISSN: 2152-7385,2152-7393
DOI: 10.4236/am.2010.16073