In this paper we study the behavior of best Lp-approximations by algebraic polynomials pairs on union of intervals, when the measure of them tends to zero.

For 1 < p < 2 we obtain sharp lower bounds for the uniform norm of products of homogeneous polynomials on Lp(µ), whenever the number of factors is no greater than the dimension of these Banach spaces (a condition readily ...

The logaritmie barrier and predictor-corretor interior point methods are applied to the Lp norm fitting problem exploiting the matrix structure in order to obtain an efficient implementation.The fitting problem has numerous ...

We study the behavior of the best simultaneous approximation to two functions from a convex set in Lp spaces, 2<p<∞, on a finite union of intervals when its measure tends to zero. In particular, we give sufficient conditions ...

In this paper we study the behavior of best Lp-approximations by rational functions to an analytic function on union of disks, when the measure of them tends to zero.

The best polynomial approximation operator was recently extended by one of the authors from Lp to Lp−1. In this paper, we study weak and strong inequalities for maximal operators related with the extended best polynomial ...

In this paper we introduce a new technique for proving norm inequalities in operator ideals with a unitarily invariant norm. Among the well-known inequalities which can be proved with this technique are the Löwner–Heinz ...

En el capítulo I presentamos el 'Teorema de convexidad de Riesz-Thorin' y diferentes aplicaciones. Y concluimos con el 'Teorema de interpolación de Riesz-Stein'. En el capítulo II, hacemos un breve estudio de 'operadores ...