“…We mention here only some papers of Hansen and Sickel [17], [18], [19], D. Dũng [5,6], Temlyakov [40,41], V. Romanyuk [30], [31] and Bazarkhanov [1], where the authors considered wavelet type dictionaries. Best n-term trigonometric approximation was studied by Temlyakov [44], [43], A. Romanyuk [25], [26], [27], [28], A. Romanyuk and V. Romanyuk [29], Stasyuk [38], [39] and others. Probably closest to us are the papers D. Dũng [7,9], where the univariate and isotropic framework is considered.…”