<em>N</em>-Widths and Average Widths of Besov Classes in Sobolev Spaces

Gui Qiao XU, Yong Sheng SUN, Yong Ping LIU

Acta Mathematica Sinica . 2006, (6): 1667 -1678 . DOI: 10.1007/s10114-005-0692-4