On the Location of Zeros of Polynomials

Complex Analysis and Operator Theory - Tập 16 - Trang 1-13 - 2021
Prasanna Kumar1, Ritu Dhankhar1
1Department of Mathematics, Birla Institute of Technology and Science Pilani, Zuarinagar, India

Tóm tắt

In this paper, we discuss the necessary and sufficient conditions for a polynomial P(z) to have all its zeros inside the open unit disc. These results involve two associated polynomials namely, the derivative of the reciprocal polynomial of P(z) and the reciprocal of the derivative of P(z). We also derive some generalizations of the classical Theorem of Laguerre.

Tài liệu tham khảo

Cauchy, A.L.: Exercises de Mathématique. Année de Bure Fréres, Paris (1829) Cohn, A.: Über die Anzahl der Wurzeln einer algebraischen Gleichung in einem Kreise. Math. Zeitschr 14, 110–138 (1922) Díaz-Barrero, J.L., Egozcue, J.J.: A generalization of the Gauss-Lucas theorem. Czec. Math. J. 58(2), 481–486 (2008) Dubinin, V.N.: Applications of Schwarz lemma to inequalities for entire functions with constraints on zeros. J. Math. Sci. 143, 3069–3076 (2007) Eneström, G.: Härledning af an allmän formel för antalet pensionärer, som vid en godtyeklig tidpunkt förefinnas inom en sluten pensionslcassa. Öfversigt af Vetenskaps-Akademiens Förhandlinger 50, 405–415 (1893) Govil, N.K., Kumar, P.: On sharpening of an inequality of Turán. Appl. Anal. Disc. Math. 13, 711–720 (2019) Govil, N.K., Rahman, Q.I.: On the Eneström-Kakeya theorem. Tohoku Math. J. 20(2), 126–136 (1968) Karamata, J.: Sur une inégalité relative aux fonctions convexes. Math. Univ. Belgrade 1, 145–148 (1932) Kumar, P.: On the inequalities concerning polynomials. Comp. Anal. Oper. Theory, 14, 65 (2020). https://doi.org/10.1007/s11785-020-01023-0 Kumar, P., Dhankhar, R.: Some refinements of inequalities for polynomials. Bull. Math. Soc. Sci. Math. Roumanie, 63 (111)(4), 359–367 (2020) Laguerre, E.: Nouvelles annales de mathématiques. Oeuvres Série 2(17), 97–101 (1878) Lax, P.D.: Proof of a conjecture due to Erdős on the derivative of a polynomial. Bull. Am. Math. Soc. 50, 509–513 (1944) Marden, M.: Geometry of polynomials. Math. Surv. 3 (1966) Schur, I.: ÜberPolynome, die nur in Innern des Einheitkreis verschwinden, Reine. Angew. Math. 148, 122–145 (1918) Turán, P.: Über die ableitung von polynomen. Comp. Math. 7, 89–95 (1939)