Li, Chong Simultaneous approximation with restricted ranges. (Chinese. English summary) Zbl 0850.41015 Math. Numer. Sin. 12, No. 1, 9-16 (1990). MSC: 41A28 Simultaneous approximation 41A50 Best approximation, Chebyshev systems Keywords:restricted ranges; best simultaneous approximations; Haar system × Cite Format Result Cite Review PDF