The basis property of the Legendre polynomials in the variable
Sbornik. Mathematics, Tome 200 (2009) no. 1, pp. 133-156
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The paper looks at the problem of determining the conditions on a variable exponent $p=p(x)$ so that the orthonormal system of Legendre polynomials $\{\widehat P_n(x)\}_{n=0}^\infty$ is
a basis in the Lebesgue space $L^{p(x)}(-1,1)$ with norm
$$
\|f\|_{p(\,\cdot\,)}=\inf\biggl\{\alpha>0:
\int_{-1}^1\biggl|{\frac{f(x)}{\alpha}}\biggr|^{p(x)}\,dx \le1\biggr\}.
$$
Conditions on the exponent $p=p(x)$, that are definitive in a certain sense,
are obtained and guarantee that the system $\{\widehat P_n(x)\}_{n=0}^\infty$
has the basis property in $L^{p(x)}(-1,1)$.
Bibliography: 31 titles.
Keywords:
variable exponent, basis.
Mots-clés : Lebesgue space, Legendre polynomial
Mots-clés : Lebesgue space, Legendre polynomial
@article{SM_2009_200_1_a4,
author = {I. I. Sharapudinov},
title = {The basis property of the {Legendre} polynomials in the variable},
journal = {Sbornik. Mathematics},
pages = {133--156},
publisher = {mathdoc},
volume = {200},
number = {1},
year = {2009},
language = {en},
url = {http://geodesic.mathdoc.fr/item/SM_2009_200_1_a4/}
}
I. I. Sharapudinov. The basis property of the Legendre polynomials in the variable. Sbornik. Mathematics, Tome 200 (2009) no. 1, pp. 133-156. http://geodesic.mathdoc.fr/item/SM_2009_200_1_a4/