Often to solve a problem one must change variables. Our belief is that for system engineering problems the changes of variables are fairly simple.
The nature of a simple effective class of changes of variables is explained in [HS99] and sketched in Chapter 31 The NCProcess output prompts for changes of variables if NCCOV → True by placing parentheses in carefully selected places. The experimental commands described in §31 actually automates this change of variable business to some extent.