Geodesic
On equiconvergence of expansions in trigonometric Fourier series and in principal functions of ordinary differential operators
Izvestiya. Mathematics, Tome 24 (1985) no. 3, pp. 567-582 
A. I. Vahabov. On equiconvergence of expansions in trigonometric Fourier series and in principal functions of ordinary differential operators. Izvestiya. Mathematics, Tome 24 (1985) no. 3, pp. 567-582. http://geodesic.mathdoc.fr/item/IM2_1985_24_3_a6/
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     author = {A. I. Vahabov},
     title = {On~equiconvergence of expansions in trigonometric {Fourier} series and in principal functions of ordinary differential operators},
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     url = {http://geodesic.mathdoc.fr/item/IM2_1985_24_3_a6/}
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Voir la notice de l'article provenant de la source Math-Net.Ru

A regularity concept is given for ordinary differential pencils of a general form in a space of vector-valued functions, and this concept is subjected to analysis. Theorems are established asserting that the Fourier series of an arbitrary vector-valued function in the system of eigenelements of the pencils is equiconvergent with the usual trigonometric Fourier series of the components of this vector-valued function. Bibliography: 7 titles.

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