Seminario NumLab: "On the constrained mock-Chebyshev least-squares"

Giovedì 28 Novembre 2013, ore 15:30 - Aula 2BC30 - Mariarosa Mazza


Giovedì 28 Novembre 2013 alle ore 15:30, in Aula 2BC30, Mariarosa Mazza (Università dell'Insubria) terrà un seminario dal titolo "On the constrained Mock-Chebyshev least-squares".

The algebraic polynomial interpolation on uniformly distributed nodes is affected by the Runge phenomenon, also when the function to be interpolated is analytic. Among all techniques that have been proposed to defeat this phenomenon, there is the mock-Chebyshev interpolation which is an interpolation made on a subset of the given nodes which elements mimic as well as possible the Chebyshev-Lobatto points. In this work we use the simultaneous approximation theory to combine the previous technique with a polynomial regression in order to increase the accuracy of the approximation of an analytic function. We give indications on how to select the degree of the simultaneous regression so as to obtain polynomial approximant good in the uniform norm and provide a sufficient condition to improve, in that norm, the accuracy of the mock-Chebyshev interpolation with a simultaneous regression. Numerical results are provided.