ABSTRACT
It is only during the last 10 years that the techniques described in this chapter have begun to be widely used by experimenters. Even now they are often considered difficult to use and of marginal utility. We intend to show that this prejudice is unjustified and we will demonstrate, with the help of several examples, that, because of their flexibility and general applicability, they have an important place in the formulator's and developer's tool kit along with the more traditional and better known methods. The long and complex calculations needed are taken care of by specialised computer programs, of which a large number are now available.
A. Recognising the Exchange Algorithm Situation
