ABSTRACT
The subject of numerical analysis-as we understand it - is the investigation and theoretical foundation of approximation methods for operator equations.
An operator is a mapping A which associates with every element of a set X one element of a set Y,
We will exclusively consider linear operators, that is we suppose X and Y to be linear spaces over the complex field C and require that A(a1x1 +a2x2) = a1 Ax1 + a2Ax2 for all elements X~t x2 of X and complex numbers a1, a2.
