Best Approximation in Finite Dimensional Subspaces of L(W, V) Original Research Article

We prove Kolmogorov′s type characterization of best approximation for given L ∈ L(W, V) in finite dimensional subspace V ⊂ L(W, V). This extends the results obtained by Malbrock for the case W = V = c0 and W = C(T), V = C(S).