Refined theorems of approximation theory in the space of $p$-absolutely continuous functions
Matematičeskie zametki, Tome 80 (2006) no. 5, pp. 701-711.

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In this paper, we prove direct and inverse theorems of approximation theory in the space of $p$-absolutely continuous functions which generalize Terekhin's results in the same way as Timan's results in $L_p$ generalize the classical theorems of approximation theory. The main theorems are refined for functions with quasimonotone Fourier coefficients and, in a number of cases, the resulats are shown to be sharp.
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S. S. Volosivets. Refined theorems of approximation theory in the space of $p$-absolutely continuous functions. Matematičeskie zametki, Tome 80 (2006) no. 5, pp. 701-711. http://geodesic.mathdoc.fr/item/MZM_2006_80_5_a5/

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