The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions

Motivated by results on the location of the zeros of a complex polynomial with monotonicity conditions on the coefficients (such as the classical Eneström–Kakeya theorem and its recent generalizations), we impose similar conditions and give bounds on the number of zeros in certain regions. We do so...

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Main Authors: Robert Gardner, Matthew Gladin
Format: Article
Language:English
Published: MDPI AG 2023-10-01
Series:AppliedMath
Subjects:
Online Access:https://www.mdpi.com/2673-9909/3/4/38
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author Robert Gardner
Matthew Gladin
author_facet Robert Gardner
Matthew Gladin
author_sort Robert Gardner
collection DOAJ
description Motivated by results on the location of the zeros of a complex polynomial with monotonicity conditions on the coefficients (such as the classical Eneström–Kakeya theorem and its recent generalizations), we impose similar conditions and give bounds on the number of zeros in certain regions. We do so by introducing a reversal in monotonicity conditions on the real and imaginary parts of the coefficients and also on their moduli. The conditions imposed are less restrictive than many of those in the current literature and hence apply to polynomials not covered by previous results. The results presented naturally apply to certain classes of lacunary polynomials. In particular, the results apply to certain polynomials with two gaps in their coefficients.
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spelling doaj.art-7a45538608ba4efcbca0a8b72bf1b48b2023-12-22T13:48:46ZengMDPI AGAppliedMath2673-99092023-10-013472272910.3390/appliedmath3040038The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity ConditionsRobert Gardner0Matthew Gladin1Department of Mathematics and Statistics, East Tennessee State University, Johnson City, TN 37614, USADepartment of Mathematics and Statistics, East Tennessee State University, Johnson City, TN 37614, USAMotivated by results on the location of the zeros of a complex polynomial with monotonicity conditions on the coefficients (such as the classical Eneström–Kakeya theorem and its recent generalizations), we impose similar conditions and give bounds on the number of zeros in certain regions. We do so by introducing a reversal in monotonicity conditions on the real and imaginary parts of the coefficients and also on their moduli. The conditions imposed are less restrictive than many of those in the current literature and hence apply to polynomials not covered by previous results. The results presented naturally apply to certain classes of lacunary polynomials. In particular, the results apply to certain polynomials with two gaps in their coefficients.https://www.mdpi.com/2673-9909/3/4/38complex polynomialscounting zerosmonotone coefficients
spellingShingle Robert Gardner
Matthew Gladin
The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions
AppliedMath
complex polynomials
counting zeros
monotone coefficients
title The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions
title_full The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions
title_fullStr The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions
title_full_unstemmed The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions
title_short The Number of Zeros in a Disk of a Complex Polynomial with Coefficients Satisfying Various Monotonicity Conditions
title_sort number of zeros in a disk of a complex polynomial with coefficients satisfying various monotonicity conditions
topic complex polynomials
counting zeros
monotone coefficients
url https://www.mdpi.com/2673-9909/3/4/38
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