Extending a Chebyshev Subspace to a Weak Chebyshev Subspace ofHigher Dimension and Related Results

[摘要] Let G={g1,…,gn} be an n-dimensional Chebyshev sub-space of C[a, b] such that 1∉G and U=(u0, u1 ,…,un ) be an (n+1)-dimensional subspace of C[a, b] where u0 =1, ui =gi , i=1….. n. Under certain restriction on G, we proved that U is a Chebyshev subspace if and only if it is a Weak Chebyshev subspace. In addition, some other related results are established.

[关键词] Chebyshev system;Weak Chebyshev system