Abstract
Bounds are obtained for the zeros of an analytic function on a disk in terms of the Taylor coefficients of the function. These results are derived using the notion of Birkhoff–James orthogonality in the sequence space \(\ell ^p\) with \(p \in (1, \infty )\), along with an associated Pythagorean theorem. It is shown that these methods are able to reproduce, and in some cases sharpen, some classical bounds for the roots of a polynomial.
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Alonso, J., Martini, H., Wu, S.: On Birkhoff orthogonality and isosceles orthogonality in normed linear spaces. Aequ. Math. 83(1–2), 153–189 (2012)
Bynum, W.L.: Weak parallelogram law for Banach spaces. Can. Math. Bull. 19(3), 269–275 (1976)
Bynum, W.L., Drew, J.H.: A weak parallelogram law for \(\ell _p\). Am. Math. Mon. 79, 1012–1015 (1972)
Cambanis, S., Hardin Jr., C.D., Weron, A.: Innovations and Wold decompositions of stable sequences. Probab. Theory Relat. Fields 79(1), 1–27 (1988)
Carothers, N.L.: A Short Course on Banach Space Theory. London Mathematical Society Student Texts, vol. 64. Cambridge University Press, Cambridge (2005)
Cheng, R., Harris, C.: Duality of the weak parallelogram laws on Banach spaces. J. Math. Anal. Appl. 404(1), 64–70 (2013)
Cheng, R., Harris, C.: Mixed norm spaces and prediction of S\(\alpha \)S moving averages. J. Time Ser. Anal. 36, 853–875 (2015)
Cheng, R., Miamee, A.G., Pourahmadi, M.: Regularity and minimality of infinite variance processes. J. Theor. Probab. 13(4), 1115–1122 (2000)
Cheng, R., Miamee, A.G., Pourahmadi, M.: On the geometry of \(L^p(\mu )\) with applications to infinite variance processes. J. Aust. Math. Soc. 74(1), 35–42 (2003)
Cheng, R., Ross, W.T.: Weak parallelogram laws on Banach spaces and applications to prediction. Period. Math. Hungar. 71(1), 45–58 (2015)
Cheng, R., Ross, W.T.: An inner-outer factorization in \(\ell ^p\) with applications to ARMA processes. J. Math. Anal. Appl. 437, 396–418 (2016)
De Terán, F., Dopico, F.M., Pérez, J.: New bounds for roots of polynomials based on Fiedler companion matrices. Linear Algebra Appl. 451, 197–230 (2014)
Duren, P.L.: Theory of \(H^{p}\) Spaces. Pure and Applied Mathematics, vol. 38. Academic Press, New York (1970)
Garcia, S.R., Mashreghi, J., Ross, W.: Introduction to Model Spaces and Their Operators. Cambridge Studies in Advanced Mathematics. Cambridge University Press, Cambridge (2016)
Hsu, S.-P., Cheng, F.-C.: On infinite families of zero bounds of complex polynomials. J. Comput. Appl. Math. 256, 219–229 (2014)
Ifantis, E.K., Kouris, C.B.: A Hilbert space approach to the localization problem of the roots of analytic functions. Indiana Univ. Math. J. 23:11–22 (1974)
Ifantis, E.K., Kouris, C.B.: Lower bounds for the zeros for analytic functions. Numer. Math. 27:239–247 (1977)
James, R.C.: Orthogonality and linear functionals in normed linear spaces. Trans. Am. Math. Soc. 61, 265–292 (1947)
Kalantari, B.: An infinite family of bounds on zeros of analytic functions and relationship to Smale’s bound. Math. Comp. 74(250), 203–220 (2005)
Marden, M.: Geometry of Polynomials, 2nd Ed. Mathematical Surveys, No. 3. American Mathematical Society, Providence (1966)
Miamee, A.G., Pourahmadi, M.: Wold decomposition, prediction and parameterization of stationary processes with infinite variance. Probab. Theory Relat. Fields 79(1), 145–164 (1988)
Rahman, Q.I., Schmeisser, G.: Analytic Theory of Polynomials. London Mathematical Society Monographs, vol. 26. New Series. The Clarendon Press, Oxford University Press, Oxford (2002)
Smale, S.: Newton’s Method Estimates from Data at One Point, pp. 185–196. The Merging of Disciplines: New Directions in Pure, Applied, and Computational Mathematics. Springer, New York (1986)
Wu, S.: A new sharpened and generalized version of Hölder’s inequality and its applications. Appl. Math. Comput. 197, 708–714 (2008)
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Communicated by Laurent Baratchart.
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Cheng, R., Mashreghi, J. & Ross, W.T. Birkhoff–James Orthogonality and the Zeros of an Analytic Function. Comput. Methods Funct. Theory 17, 499–523 (2017). https://doi.org/10.1007/s40315-017-0191-5
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DOI: https://doi.org/10.1007/s40315-017-0191-5
Keywords
- Analytic function
- Roots of polynomials
- Orthogonality
- Localization of zeros
- Banach space geometry
- Separation of zeros