Velikin, V. L. Approximation in a Banach space by a convergent sequence of subspaces of fixed dimension. (English) Zbl 0709.41513 Proc. Steklov Inst. Math. 180, 92-94 (1989). MSC: 41A65 Abstract approximation theory (approximation in normed linear spaces and other abstract spaces) PDF BibTeX XML Cite \textit{V. L. Velikin}, Proc. Steklov Inst. Math. 180, 92--94 (1989; Zbl 0709.41513)