Abstract
We study the Nikol’skii inequality for algebraic polynomials on the interval [−1, 1] between the uniform norm and the norm of the space L (α,β) q , 1 ≤ q < ∞, with the Jacobi weight ϕ(α,β)(x) = (1 − x)α(1 + x)β, α ≥ β > −1. We prove that, in the case α > β ≥ −1/2, the polynomial with unit leading coefficient that deviates least from zero in the space L (α+1,,β) q with the Jacobi weight ϕ (α+1,β)(x) = (1−x)α+1(1+x)β is the unique extremal polynomial in the Nikol’skii inequality. To prove this result, we use the generalized translation operator associated with the Jacobi weight. We describe the set of all functions at which the norm of this operator in the space L (α,β) q for 1 ≤ q < ∞ and α > β ≥ −1/2 is attained.
Similar content being viewed by others
References
V. V. Arestov, Inequality of different metrics for trigonometric polynomials, Math. Notes, 27:4 (1980), 265–269.
V. V. Arestov, On integral inequalities for trigonometric polynomials and their derivatives, Izv. AN SSSR, Ser. Mat., 45:1 (1981), 3–22 (in Russian); translated in Math. USSR Izv., 18:1 (1982), 1–17.
V. V. Arestov and M. V. Deikalova, Nikolskii inequality for algebraic polynomials on a multidimensional Euclidean sphere, Trudy Inst. Mat. Mekh. Ural’sk. Otdel. Ross. Akad. Nauk, 19:2 (2013), 34–47 (in Russian); translated in Proc. Steklov Inst. Math., 284 (suppl. 1) (2014), S9–S23.
V. Arestov and M. Deikalova, Nikol’skii inequality between the uniform norm and L q-norm with ultraspherical weight of algebraic polynomials on an interval, Comput. Methods Funct. Theory, 15 (2015), 689–708.
V. V. Arestov and P. Yu. Glazyrina, Sharp integral inequalities for fractional derivatives of trigonometric polynomials, J. Approx. Theory 164 (2012), 1501–1512.
R. Askey, Orthogonal polynomials and special functions, SIAM (Philadelphia, Pa, 1975).
R. Askey and S. Wainger, A convolution structure for Jacobi series, Amer. J. Math., 91 (1969), 463–485.
A. G. Babenko, An exact Jackson–Stechkin inequality for L2-approximation on the interval with the Jacobi weight and on projective spaces, Izv. Math., 62:6 (1998), 1095–1119.
A. G. Babenko, Yu. V. Kryakin, and V. A. Yudin, On a result by Geronimus, Trudy Inst. Mat. Mekh. Ural’sk. Otdel. Ross. Akad. Nauk, 16:4 (2010), 54–64 (in Russian); translated in Proc. Steklov. Inst. Math., 273 (suppl. 1) (2011), 37–48.
V. Babenko, V. Kofanov, and S. Pichugov, Comparison of rearrangement and Kolmogorov–Nagy type inequalities for periodic functions, in Approximation theory: A volume dedicated to Blagovest Sendov, Ed. by B. Bojanov, Darba (Sofia, 2002), pp. 24–53.
V. M. Badkov, Asymptotic and extremal properties of orthogonal polynomials with singularities in the weight, Trudy Mat. Inst. Steklov, 198 (1992), 41–88 (in Russian); translated in Proc. Steklov Inst. Math. 198 (1994), 37–82.
H. Bavinck, A special class of Jacobi series and some applications, J. Math. Anal. Appl., 37 (1972), 767–797.
S. N. Bernstein, Collected works, vol. 1, Izd. Akad. Nauk SSSR (Moscow, 1952).
B. Bojanov, Polynomial inequalities, in: Proc. Int. Conf. “Open Problems in Approximation Theory” (Voneshta voda, Bulgaria, June 18–24, 1993), Science Culture Technology Publishing (Singapore, 1994), pp. 25–42.
P. Borwein and T. Erdélyi, Polynomials and polynomial inequalities, Graduate Texts in Mathemathics, 161, Springer New York, 1995).
A. P. Calderon and G. Klein, On an extremum problem concerning trigonometrical polynomials, Studia Math., 12 (1951), 166–169.
P. L. Chebyshev, Theory of mechanisms known as parallelograms, in: Complete Collection of Works in Five Volumes, Vol. 2, Mathematical Analysis, Izd. Akad. Nauk SSSR (Moscow, 1947), pp. 23–51 (in Russian).
I. K. Daugavet and S. Z. Rafal’son, Certain inequalities of Markov–Nikolskii type for algebraic polynomials, Vestnik Leningrad. Univ., 1 (1972), 15–25.
M. V. Deikalova and V. V. Rogozina, Jackson–Nikol’skii inequality between the uniform and integral norms of algebraic polynomials on a Euclidean sphere, Trudy Inst. Mat. Mekh. Ural’sk. Otdel. Ross. Akad. Nauk, 18:4 (2012), 162–171.
R. A. DeVore and G. G. Lorentz, Constructive Approximation, Springer Berlin, New York, 1993).
Z. Ditzian and S. Tikhonov, Ul’yanov and Nikol’skii-type inequalities, J. Approx. Theory, 133 (2005), 100–133.
G. Gasper, Positivity and the convolution structure for Jacobi series, Ann. Math., 93 (1971), 112–118.
J. Geronimus, Sur quelques propriétés extrémales de polynomes dont les coefficients premiers sont donnés, Soobshch. Khar’k. Mat. O-va, 12 (1935), 49–59.
V. E. Gheit, On polynomials that deviate least from zero in the metric of L[1, 1] (third communication), Sib. Zh. Vychisl. Mat., 6:1 (2003), 37–57 (in Russian).
V. E. Gheit and V. V. Gheit, Polynomials of least deviation from zero in the L[-1, 1] metric with five fixed coefficients, Sib. Zh. Vychisl. Mat., 12:1 (2009), 29–40 (in Russian); translated in Numer. Anal. Appl., 2:1 (2009), 24–33.
P. Yu. Glazyrina, The Markov brothers inequality in L0-space on an interval, Math. Notes, 78:1-2 (2005), 53–58.
P. Yu. Glazyrina, Markov–Nikol’skii inequality for the spaces Lq, L0 on a segment, Trudy Inst. Mat. Mekh. Ural’sk. Otdel. Ross. Akad. Nauk 11:2 (2005), 60–71 (in Russian); translated in Proc. Steklov Inst. Math. (2005) (suppl. 2), S104–S116.
P. Yu. Glazyrina, The sharp Markov–Nikolskii inequality for algebraic polynomials in the spaces Lq and L0 on a closed interval, Math. Notes, 84:1–2 (2008), 3–21.
D. V. Gorbachev, Selected Problems in Functional Analysis and Approximation Theory and Their Applications, Grif i K (Tula, 2004) (in Russian).
D. V. Gorbachev, An integral problem of Konyagin and the (C,L)-constants of Nikol’skii, Trudy Inst. Mat. Mekh. URO RAN, 11:2 (2005), 72–91 (in Russian); translated in Proc. Steklov Inst. Math. (2005) (suppl. 2), S117–S138.
V. I. Ivanov, Certain inequalities in various metrics for trigonometric polynomials and their derivatives, Math. Notes, 18:4 (1975), 880–885.
V. I. Ivanov, Some extremal properties of polynomials and inverse inequalities of approximation theory, Trudy MIAN SSSR, 145 (1980), 79–110 (in Russian); translated in Proc. Steklov Inst. Math., 145 (1981), 85–120.
D. Jackson, Certain problems of closest approximation, Bull. Amer. Math. Soc., 39 (1933), 889–906.
V. A. Kofanov, Sharp inequalities of Bernstein and Kolmogorov type, East J. Approx., 11 (2005), 131–145.
S. V. Konyagin, Bounds on the derivatives of polynomials, Dokl. Akad. Nauk SSSR, 243:5 (1978), 1116–1118 (in Russian); translated in Soviet Math. Dokl., 19:6 (1978), 1477–1480.
T. Koornwinder, Jacobi polynomials. An analytic proof of the product formula, SIAM J. Math. Anal., 5 (1974), 125–137.
A. Korkine and G. Zolotareff, Sur une certain minimum, Nouv. Ann. Math., Ser. 2, 12 (1873), 337–355; Collected papers of A. N. Korkin, St. Petersburg Univ. (St. Petersburg, 1911), Vol. 1, pp. 329–349.
N. P. Korneichuk, Extremal Problems of Approximation Theory, Nauka Moscow, 1976) (in Russian).
N. P. Korneichuk, V. F. Babenko, and A. A. Ligun, Extremal properties of polynomials and splines, Naukova Dumka Kiev, 1992) (in Russian); translated Nova Science Publishers (Commack, NY, 1996).
Le A. M. Gendre, Exercices de calcul intégral sur divers ordres de transcendantes et sur les quadratures, 2 (Paris, 1817).
A. L. Lukashov, On Chebyshev–Markov rational functions over several intervals, J. Approx. Theory, 95 (1998), 333–352.
A. Lukashov and S. Tyshkevich, On trigonometric polynomials deviating least from zero on an interval, J. Approx. Theory, 168 (2013), 18–32.
A. Lupas, An inequality for polynomials, Univ. Beograd. Publ. Electrotehn. Fak. Sep. Mat. Fiz., 461–497(1974), 241–243.
G. V. Milovanović, D. S. Mitrinović, and Th. M. Rassias, Topics in Polynomials: Extremal Problems, Inequalities, Zeros, World Scientific Singapore, 1994).
S. M. Nikol’skii, Inequalities for entire functions of finite degree and their application in the theory of differentiable functions of several variables, Trudy MIAN SSSR, 38 (1951), 244–278 (in Russian).
S. M. Nikol’skii, Approximation of Functions of Several Variables and Imbedding Theorems, Nauka Moscow, 1977) (in Russian).
F. Peherstorfer, On the representation of extremal functions in the L1-norm, J. Approx. Theory, 27 (1978), 61–75.
F. Peherstorfer, Trigonometric polynomial approximation in the L1-norm, Math. Z., 169 (1979), 261–269.
G. Pólya and G. Szegő, Problems and Theorems in Analysis, Vol. 2, Springer Berlin, New York, 1972).
Q. I. Rahman and G. Schmeisser, Analytic Theory of Polynomials, Oxford Univ. Press Oxford, 2002).
E. B. Saff and T. Sheil-Small, Coefficient and integral mean estimates for algebraic and trigonometric polynomials with restricted zeros, J. London Math. Soc., 9 (1974), 16–22.
I. E. Simonov, Sharp Markov brothers type inequality in the spaces L p and L 1 on a closed interval, Trudy Inst. Mat. Mekh. URO RAN, 17:3 (2011), 282–290 (in Russian); translated in Proc. Steklov Inst. Math., 277 (suppl. 1) (2012), S161–S170.
I. E. Simonov, A sharp Markov brothers-type inequality in the spaces L8 and L1 on the segment, Math. Notes, 93:3–4 (2013), 607–615.
I. E. Simonov, Trigonometric polynomials with fixed leading coefficients that deviate least from zero in the integral norm, in: Contemporary Problems of Function Theory and Their Applications, Proceedings of XVIII International Saratov Winter School, Izdatel’stvo “Nauchnaya kniga” (Saratov, 2016), pp. 253–255.
I. E. Simonov and P. Yu. Glazyrina, Sharp Markov–Nikolskii inequality with respect to the uniform norm and the integral norm with Chebyshev weight, J. Approx. Theory, 192 (2015), 69–81.
P. K. Suetin, Classical Orthogonal Polynomials, Fizmatlit (Moscow, 2005) (in Russian).
G. Szegő, Orthogonal polynomials, Amer. Math. Soc. (New York, 1959).
G. Szegő and A. Zygmund, On certain mean values of polynomials, J. Anal. Math., 3 (1953), 225–244.
L. V. Taikov, A generalization of an inequality of S. N. Bernstein, Trudy Mat. Inst. Steklov, 78 (1965), 43–47 (in Russian); translated in Proc. Steklov Inst. Math., 78 (1967), 43–48.
L. V. Taikov, A group of extremal problems for trigonometric polynomials, Uspekhi Mat. Nauk, 20:3 (1965), 205–211 (in Russian).
L. V. Taikov, On the best approximation of Dirichlet kernels, Math. Notes, 53:6 (1993), 640–643.
V. M. Tikhomirov, Some Questions of Approximation Theory, Izd.Mosk. Gos. Univ. Moscow, 1976) (in Russian).
A. F. Timan, Theory of Approximation of Functions of a Real Variable, Fizmatgiz Moscow, 1960) (in Russsian); translated Pergamon (New York, 1963).
G. N. Watson, A Treatise on the Theory of Bessel Functions. Part 1, Cambridge Univ. Press Cambridge, 1995).
A. Zygmund, Trigonometric Series, Vol. 2, Cambridge Univ. Press Cambridge, 1959).
Author information
Authors and Affiliations
Corresponding author
Additional information
This work was supported by the Russian Foundation for Basic Research (project no. 15-01-02705) and by the Competitiveness Enhancement Program of the Ural Federal University (Enactment of the Government of the Russian Federation no. 211, agreement no. 02.A03.21.0006).
Rights and permissions
About this article
Cite this article
Arestov, V., Deikalova, M. Nikol’skii inequality between the uniform norm and L q -norm with jacobi weight of algebraic polynomials on an interval. Anal Math 42, 91–120 (2016). https://doi.org/10.1007/s10476-016-0201-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10476-016-0201-2