Generalized growth and approximation of entire function solution of Helmholtz equation in Banach spaces
Article
First Online:
Received:
Accepted:
- 84 Downloads
- 2 Citations
Abstract
In this paper, we study the generalized growth and polynomial approximation of entire function solution of Helmholtz equation in \(R^2\) in Smirnov spaces [\(\varepsilon _p (S)\) and \(\varepsilon ^{^\prime }_p(S), 1\le p\le \infty \)] where S is finitely simply connected domain in the complex plane with the boundary that belongs to the Al’per class (Izv AN SSSR Ser Matem 19(3):423–444, 1955). Some bounds on generalized order and generalized type of entire solution of Helmholtz equation have been obtained in terms of the coefficients and approximation errors using function theoretic methods. Our results extend and improve the results of Kumar (J Appl Anal 18:179–196, 2012).
Keywords
Generalized order and type Helmholtz equation Polynomial approximation Smirnov spaceMathematics Subject Classification
30B10 41A10References
- 1.Al’per, Ya.S.: On uniform approximation of functions of complex variables in a closed domain. Izv. AN SSSR. Ser. Matem. 19(3), 423–444 (1955)Google Scholar
- 2.Batyrev, A.V.: On the question of best approximation of analytic functions by polynomials. Dokl. AN SSSR 76(2), 173–175 (1951)MathSciNetGoogle Scholar
- 3.Bergman, S.: Integral operators in the theory of linear partial differential equations. In: Ergeb. Math. Grenzgeb., vol. 23. Springer, New York (1969)Google Scholar
- 4.Bernstein, S.N.: Extremal Properties of Polynomials (in Russian). ONTI, Moscow-Leningrad (1937)Google Scholar
- 5.Bernstein, S.N.: On the Best Approximation of Continuous Functions by Polynomials of a Given Degree, in Colleciton of Works by S.N. Bernstein (in Russian), vol. 1, pp. 11–104. AN SSSR, Moscow (1952)Google Scholar
- 6.Gilbert, R.P., Colton, D.L.: Singularties of solutions to elliptic partial differential equations. Q. J. Math. 19, 391–396 (1968)MathSciNetCrossRefMATHGoogle Scholar
- 7.Giroux, A.: Approximation of entire functions over bounded domains. J. Approx. Theory 28(1), 45–53 (1980)MathSciNetCrossRefMATHGoogle Scholar
- 8.Ibragimov, I.I., Shikhaliev, N.I.: On the best polynomial approximation in a space of analytic functions. Dokl. AN SSSR 227(2), 280–283 (1976)MathSciNetMATHGoogle Scholar
- 9.Ibragimov, I.I., Shikhaliev, N.I.: On the construction characteristic of a class of functions of complex variable. Dokl. AN SSSR 236(4), 789–791 (1977)Google Scholar
- 10.Kapoor, G.P., Nautiyal, A.: Polynomial approximation of an entire function of slow growth. J. Approx. Theory 32, 64–75 (1981)MathSciNetCrossRefMATHGoogle Scholar
- 11.Kreyszig, E.O., Kracht, M.: Methods of complex analysis in partial differential equations with applications. In: Can. Math. Soc. Ser. Monogr. Adv. Texts. Wiley, New York (1988)Google Scholar
- 12.Kumar, D.: Approximation of entire function solutions of Helmholtz equation having slow growth. J. Appl. Anal. 18, 179–196 (2012)MathSciNetCrossRefMATHGoogle Scholar
- 13.McCoy, P.A.: Solution of the Helmholtz equation having rapid growth. Complex Var. Elliptic Equ. 18, 91–101 (1992)MathSciNetCrossRefMATHGoogle Scholar
- 14.Nautiyal, A.: On the growth of entire solutions of generalized axially symmetric Helmholtz equation. Indian J. Pure Appl. Math. 14, 718–721 (1983)MathSciNetMATHGoogle Scholar
- 15.Reddy, A.R.: Approximation of an entire function. J. Approx. Theory 3(1), 128–137 (1970)Google Scholar
- 16.Reddy, A.R.: Best polynomial approximation to certain entire fucntions. J. Approx. Theory 5, 97–112 (1972)CrossRefMATHGoogle Scholar
- 17.Reddy, A.R.: A contribution to best approximation in the \(L_2\) norm. J. Approx. Theory 1(1), 110–117 (1974)CrossRefMATHGoogle Scholar
- 18.Sheremeta, M.N.: On the connection beetween the growth of the maximum modulus of an entire function and the moduli of coefficients of its power expansion. Izv. Vuzov. Mat. (2), 100–108 (1967)Google Scholar
- 19.Sheremeta, M.N.: On the connection between the growth of zero-order functions which are entire or analytic in a circle and coefficients of their power expansions. Izv. Vuzov. Mat. (6), 115–121 (1968)Google Scholar
- 20.Sheremeta, M.N.: On the connection between the growth of the maximum modulus of an entire function and the moduli of the coefficients of its power series expansion. Am. Math. Soc. Transl. 88, 291–301 (1970)MATHGoogle Scholar
- 21.Suetin, P.K.: Series of Faber Polynomials. Gordon and Breach, New York (1968)MATHGoogle Scholar
- 22.Vakarchuk, S.B.: On the best polynomial approximation of functions analytic in the unit circle in some Banach spaces. Math. Zamet. 55(4), 6–14 (1994)MathSciNetGoogle Scholar
- 23.Vakarchuk, S.B.: On the best approximation of analytic functions of two complex variables by generalized polynomials in some space. Izv. Vuzov. Mat. (7), 14–25 (1991)Google Scholar
- 24.Vakarchuk, S.B.: On the best polynomial approximations in some Banach spaces of analytic functions. Dopov. AN Ukr SSR Ser. A (1), 8–10 (1991)Google Scholar
- 25.Vakarchuk, S.B.: On the best polynomial approximation of entire transcendental functions in some Banach spaces I. Ukr. Mat. Zh. 47(9), 1123–1133 (1994)MathSciNetMATHGoogle Scholar
- 26.Vakarchuk, S.B.: On the best polynomial approximation of entire transcendental functions in some Banach spaces II. Ukr. Mat. Zh. 47(10), 1318–1322 (1994)Google Scholar
- 27.Vakarchuk, S.B., Zhir, S.I.: On the polynomial approximation of entire transcendental functions. Mat. Fiz. Anal. Geom. 9(4), 595–603 (2002)Google Scholar
- 28.Vakarchuk, S.B., Zhir, S.I.: Some questions of the polynomial approximation of entire transcendental functions. Ukr. Mat. Zh. 54(9), 1155–1162 (2002)MathSciNetCrossRefMATHGoogle Scholar
- 29.Vakarchuk, S.B., Zhir, S.I.: Polynomial approximation of entire functions of generalized order in the unit disk. In: Abstracts. Int. Akhiezer Centenary Conference at the Inst. for Low Temp. Physics and Eng., pp. 98–99. Kharkov Nat. Univ., Kharkov (2001)Google Scholar
- 30.Vakarchuk, S.B., Zhir, S.I.: On the polynomial approximation of entire transcendental functions in the complex plane. In: Problems of the Theory of Approximation of Functions and Adjacent Problems (in Ukrainian), pp. 27–42. Inst. of Math. of the Ukr. Academy of Sci., Kiev (2005)Google Scholar
- 31.Vakarchuk, S.B., Zhir, S.I.: On the best polynomial approximation of entire transcendental functions of generalized order. Ukr. Mat. Zh. 60(8), 1011–1026 (2008)MathSciNetCrossRefMATHGoogle Scholar
- 32.Vakarchuk, S.B., Zhir, S.I.: On some problems of polynomial approximation of entire transcendental functions. Ukr. Math. J. 54, 1393–1401 (2002)MathSciNetCrossRefMATHGoogle Scholar
- 33.Vakarchuk, S.B., Zhir, S.I.: The best polynomial approximation of entire transcendental functions with generalized growth order in Banach spaces \({\varepsilon ^{\prime }}_p(G)\) and \(\varepsilon _p(G), p\ge 1\). J. Math. Sci. 179(2), 300–327 (2001)MathSciNetCrossRefGoogle Scholar
- 34.Varga, R.S.: On an extension of a result of S.N. Bernstein. J. Approx. Theory 1(2), 176–179 (1968)MathSciNetCrossRefMATHGoogle Scholar
- 35.Zhir, S.I., Vakarchuk, S.B.: On the best polynomial approximation of entire transcendental functios in the Smirnov spaces. In: Modern Methods in the Theory of Functions and Adjacent Problems, Conference “Voronezh Winter Math School” (in Russian), Voronezh, pp. 98–99 (2003)Google Scholar
Copyright information
© Università degli Studi di Ferrara 2015