Abstract
We investigate the direct and inverse theorems for trigonometric polynomials in the Morrey space \({{\mathcal {M}}}^{p(\cdot ),\lambda (\cdot )}\) with variable exponents. For this space, we obtain estimates of the K-functional in terms of the modulus of smoothness and the Bernstein type inequality for trigonometric polynomials.
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V. S. Guliyev: The research of V.S. Guliyev was partially supported by the grant of 1st Azerbaijan-Russia Joint Grant Competition (the Agreement number No. 18-51-06005). The research of V.S. Guliyev and Yoshihiro Sawano is partially supported by the Ministry of Education and Science of the Russian Federation (the Agreement number: 02.a03.21.0008). Yoshihiro Sawano is partially supported by 16K05209 JSPS.
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Guliyev, V.S., Ghorbanalizadeh, A. & Sawano, Y. Approximation by trigonometric polynomials in variable exponent Morrey spaces. Anal.Math.Phys. 9, 1265–1285 (2019). https://doi.org/10.1007/s13324-018-0231-y
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DOI: https://doi.org/10.1007/s13324-018-0231-y