## Collocation for singular integral equations with fixed singularities of particular Mellin type

Peter Junghanns, Robert Kaiser, and Giuseppe Mastroianni

### Abstract

This paper is concerned with the stability of collocation methods for Cauchy singular integral equations with fixed singularities on the interval $[-1,1]$. The operator in these equations is supposed to be of the form $a\mathcal{I}+b\mathcal{S}+\mathcal{B}^\pm$ with piecewise continuous functions $a$ and $b$. The operator $\mathcal{S}$ is the Cauchy singular integral operator and $\mathcal{B}^\pm$ is a finite sum of integral operators with fixed singularities at the points $\pm1$ of special kind. The collocation methods search for approximate solutions of the form $\nu(x)p_n(x)$ or $\mu(x)p_n(x)$ with Chebyshev weights $\nu(x)=\sqrt{\frac{1+x}{1-x}}$ or $\mu(x)=\sqrt{\frac{1-x}{1+x}}$, respectively, and collocation with respect to Chebyshev nodes of first and third or fourth kind is considered. For the stability of collocation methods in a weighted $\mathbf{L}^2$-space, we derive necessary and sufficient conditions.

Full Text (PDF) [602 KB], BibTeX

### Key words

collocation method, stability, $C^*$-algebra, notched half plane problem

65R20, 45E05

### Links to the cited ETNA articles

 [12] Vol. 14 (2002), pp. 79-126 P. Junghanns and A. Rathsfeld: A polynomial collocation method for Cauchy singular integral equations over the interval [13] Vol. 17 (2004), pp. 11-75 P. Junghanns and A. Rogozhin: Collocation methods for Cauchy singular integral equations on the interval

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