On optimal approximation in periodic Besov spaces

Abstract

We work with spaces of periodic functions on the d-dimensional torus. We show that estimates for L∞-approximation of Sobolev functions remain valid when we replace L1 by the isotropic periodic Besov space B01;1 or the periodic Besovspace with dominating mixed smoothness S01;1B. For t > 1=2, we also prove estimates for L2-approximation of functions in the Besov space of dominating mixed smoothness St 1;1B, describing exactly the dependence of the involved constants on the dimension d and the smoothness t.