For substituting kernels in standard forms or standard quotients by other kernels or arbitrary algebraic expressions the following functions are available :
|subf(f,a)||substitute a in SF f|
|subsq(q,a)||substitute a in SQ q|
where a is a list of pairs, each with a kernel to be replaced in the car and its replacement as algebraic form in the cdr 13, e.g.
Here x is replaced by 5 while y is replaced by a + b.