Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-10T14:01:22.752Z Has data issue: false hasContentIssue false

On Value Distribution Theory of Second Order Periodic ODEs, Special Functions and Orthogonal Polynomials

Published online by Cambridge University Press:  20 November 2018

Yik-Man Chiang
Affiliation:
Department of Mathematics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, P.R. China e-mail: machiang@ust.hk
Mourad E. H. Ismail
Affiliation:
Department of Mathematics, University of Central Florida, Orlando, FL 32816, U.S.A. e-mail: ismail@math.ucf.edu
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We show that the value distribution (complex oscillation) of solutions of certain periodic second order ordinary differential equations studied by Bank, Laine and Langley is closely related to confluent hypergeometric functions, Bessel functions and Bessel polynomials. As a result, we give a complete characterization of the zero-distribution in the sense of Nevanlinna theory of the solutions for two classes of the ODEs. Our approach uses special functions and their asymptotics. New results concerning finiteness of the number of zeros (finite-zeros) problem of Bessel and Coulomb wave functions with respect to the parameters are also obtained as a consequence. We demonstrate that the problem for the remaining class of ODEs not covered by the above “special function approach” can be described by a classical Heine problem for differential equations that admit polynomial solutions.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2006

References

[1] Abramowitz, M. and Stegun, I. A. (eds.), Handbook of Mathematical Functions. National Bureau of Standards, Applied Mathematics Series 55, Washington, 1964.Google Scholar
[2] Andrews, G. E., Askey, R., and Roy, R., Special Functions. Encyclopedia of Mathematics and its Applications 71, Cambridge University Press, Cambridge, 1999.Google Scholar
[3] Bank, S. B., Three results in the value-distribution theory of solutions of linear differential equations. Kodai Math. J. 9(1986), no. 2, 225240.Google Scholar
[4] Bank, S. B., On the explicit determination of certain solutions of periodic differential equations. Complex Variables Theory Appl. 23(1993), no. 1-2, 101121.Google Scholar
[5] Bank, S. B., A note on the oscillation of solutions of periodic linear differential equations. Czechoslovak Math. J. 44(119)(1994), no. 1, 91107.Google Scholar
[6] Bank, S. B. and Laine, I., On the oscillation theory of. f′′ + Af = 0 where A is entire. Trans. Amer. Math. Soc. 273(1982), no. 1, 351363.Google Scholar
[7] Bank, S. B. and Laine, I., Representations of solutions of periodic second order linear differential equations. J. Reine Angew.Math. 344(1983), 121.Google Scholar
[8] Bank, S. B., Laine, I., and Langley, J. K., On the frequency of zeros of solutions of second order linear differential equations. Results Math. 10(1986), 824.Google Scholar
[9] Bank, S. B., Laine, I., and Langley, J. K., Oscillation results for solutions of linear differential equations in the complex domain. Results Math. 16(1989), no. 1-2, 315.Google Scholar
[10] Bochner, S., Über Sturm–Liouvillsche polynomsysteme. Math. Z. 29(1929), no. 1, 730736.Google Scholar
[11] Buchholz, H., The Confluent Hypergeometric FunctionWith Special Emphasis on Its Applications. Berlin, Springer-Verlag, 1969.Google Scholar
[12] Burchnall, J. L. and Chaundy, T. W., The commutative ordinary differential operators II – The identity Pn = Qm. Proc. Royal Soc. London Ser. A 134(1931), 471–485.Google Scholar
[13] Chiang, Y. M., On the complex oscillation of y′′ + (ezK)y = 0 and a result of Bank, Laine and Langley . In: Computational Methods and Function Theory, Ser. Approx. Decompos. 5, World Scientific, River Edge, NJ, 1995, 125134.Google Scholar
[14] Chiang, Y. M., On the zero-free solutions of linear periodic differential equations in the complex plane. Results Math. 38(2000), no. 3-4, 213225.Google Scholar
[15] Cruz, A., Esparza, J., and Sesma, J., Zeros of the Hankel functions of real order out of the principal Riemann sheet. J. Comp. Appl. Math. 37(1991), no. 1-3, 8999.Google Scholar
[16] Curtis, A. R., Coulomb Wave Functions. Royal Society Mathematical Tables II, Cambridge University Press, New York, 1964.Google Scholar
[17] Dzieciol, A., Yngve, S., and Fröman, P. O., Coulomb wave functions with complex values of the variable and the parameters. J. Math. Physics, 40(1999), no. 12, 61456166.Google Scholar
[18] Erdélyi, A., ed, Higher Transcendental Functions. Vol. II, McGraw-Hill, New York 1953.Google Scholar
[19] Esparza, J. and Sesma, J., Regge Trajectories for the inverse square potential. J. Math. Physics, 11(1970), 32453250.Google Scholar
[20] Esparza, J., López, J. L., and Sesma, J., Zeros of the Whittaker function associated to Coulomb waves. IMA J. Appl. Math. 63(1999), no. 1, 7187.Google Scholar
[21] Frei, M., Über die subnormalen Lösungen der Differentialgleichung w′′ + e –z w′ + konst. w = 0. Comment Math. Helv. 36(1961), 18.Google Scholar
[22] Gao, S., Some results on the complex oscillation theory of periodic second-order linear differential equations. Kexue Tongbao 33(1988), no. 13, 10641068.Google Scholar
[23] Grosswald, E., Bessel Polynomials. Lecture Notes in Math. 698, Springer-Verlag, Berlin, 1978.Google Scholar
[24] Gundersen, G. G. and Steinbart, E. M., Subnormal solutions of second order linear differential equations with periodic coefficients. Results Math. 25(1994), no. 3-4, 270289.Google Scholar
[25] Hayman, W. K., Meromorphic Functions. Clarendon Press, Oxford, 1964.Google Scholar
[26] Heine, E., Handbuch der Kugelfunctionen, Theorie und Anwendungen. 1. Second ed. Reimer, Berlin, 1878.Google Scholar
[27] Hull, M. H. Jr., and Breit, G., Coulomb Wave Functions. Handbuch der Physik 41/1, Springer, Berlin, 1959, pp. 408465.Google Scholar
[28] Hille, E., Ordinary Differential Equations in the Complex Domains. Wiley-Interscience, 1976.Google Scholar
[29] Ismail, M. E. H., An electrostatic model for zeros of general orthogonal polynomials. Pacific J. Math. 193(2000), no. 2, 355369.Google Scholar
[30] Ismail, M. E. H., Lin, S. S. and Roan, S. S., Bethe Ansatz equation of XXZ model and q-Sturm-Louville problems (to appear).Google Scholar
[31] Kamke, E., Differentialgleichungen, Lösungsmethoden und Lösungen. Akademische Verlagsgesellschaft, Leipzig, 1943.Google Scholar
[32] Keller, J. B., S. Rubinow, I. and Goldstein, M., Zeros of Hankel functions and poles of scattering amplitudes. J. Math. Physics 4(1963), 829832.Google Scholar
[33] Krall, H. L. and Frink, O., A new class of orthogonal polynomials: The Bessel polynomials. Trans. Amer. Math. Soc. 65(1949), 100115.Google Scholar
[34] Laine, I., Nevanlinna Theory and Complex Differential Equations. de Gruyter Studies in Mathematics 15, Walter de Gruyter, Berlin, 1993.Google Scholar
[35] Lommel, E., Zur Theorie der Bessel’schen Functionen. Math. Ann. 3(1871), no. 4, 475487.Google Scholar
[36] Pearson, K., On the solution of some differential equations by Bessel's functions. Messenger of Math. IX(1880), 127131.Google Scholar
[37] Skorokhodov, S. L., On the computation of complex zeros of the modified Bessel function of the second kind. Soviet Math. Dokl. 31, No. 5, (1985), 7881.Google Scholar
[38] Szegő, G., Orthogonal Polynomials. Fourth ed. American Mathematical Society Colloquium Publications 23, American Mathematical Society, Providence, RI, 1975,Google Scholar
[39] Thompson, I. J. and Barnett, A. R., Coulomb and Bessel Functions of complex arguments and order. J. Comput. Phys. 64(1986), no. 2, 490509.Google Scholar
[40] Watson, G. N., A Treatise on the Theory of Bessel Functions. Second edition. Cambridge University Press, Cambridge, 1944.Google Scholar
[41] Watson, G. N., The defraction of electric waves by the earth. Proc. Roy. Soc. London A95(1918), No. 666 8399.Google Scholar
[42] Whittaker, E. T. and Watson, G. N., A Course of Modern Analysis. Fourth ed. Cambridge University Press, Cambridge, 1927, (reprinted in 1996).Google Scholar
[43] Wittich, H., Subnormale Lösungen der Differentialgleichung w′′ + p(ez)w′ + q(ez)w = 0. Nagoya Math. J. 30(1967), 2937.Google Scholar