Lipschitz continuity and Gateaux differentiability of the best approximation operator in vector-valued Chebyshev approximation

Some Results on p-Best Approximation in Vector Spaces

Best Approximation in TVS

In this paper  we give newresults on the best approximation  in the Hausdorff topological vectorspace and  consider relationship  with orthogonality. Also we determined under  what conditions the map $P_{K,f}$ is upper semicontinous.

Continuity Properties of Best Analytic Approximation

Let A be the operator which assigns to each m×n matrix-valued function on the unit circle with entries in H∞+C its unique superoptimal approximant in the space of bounded analytic m × n matrix-valued functions in the open unit disc. We study the continuity of A with respect to various norms. Our main result is that, for a class of norms satifying certain natural axioms, A is continuous at any f...

Best Lipschitz constant of the trapezoidal approximation operator preserving the expected interval

In this paper, we prove new distance properties between a fuzzy number and its trapezoidal approximation preserving the expected interval. Then, we find the best Lipschitz constant of the trapezoidal approximation operator preserving the expected interval. Finally, we use this result in finding within a reasonable error the trapezoidal approximation of a fuzzy number preserving the expected int...

Variations on the Chebyshev and Lq Theories of Best Approximation

The classical Chebyshev theory of best uniform approximation to continuous functions by polynomials of degree <n was initiated by Chebyshev in [2]. This theory has a distinct advantage over the corresponding ones for L4-norms, 1 < q < co, in that the unique best approximant is characterized by a remarkable geometric property. Let f be a realvalued function, continuous on [0, 11, and, for n = 0,...