18.7 Extensions to More Than Four Dimensions

In our discussion so far, we have assumed that we are working in the normal four dimensions of QED calculations. However, in most cases, the programs will also work in an arbitrary number of dimensions. The command

vecdim expressionterminator

sets the appropriate dimension. The dimension can be symbolic as well as numerical. Users should note however, that the EPS operator and the γ5 symbol (A) are not properly defined in other than four dimensions and will lead to an error if used.