4.10 Useful facilities for standard forms

4.10.1 Kernel list

The function kernels extracts all kernels from a standard form and returns them as list.

    kernels numr simp ’(plus (expt x 3)(expt y 4));

will result in (xy).

4.10.2 Greatest common divisor

The greatest common divisor of two polynomials is computed by the function *gcdf. It takes as arguments two standard forms and returns a standard form or a 1 if there is no non trivial common divisor.

4.10.3 Factorization

The function fctrf is the interface for calling the factorizer. It takes a standard form as parameter and returns a list which contains

So calling fctrf for 2x2 - 2 will result in

(2 ((((X . 1) . 1) . 1) . 1) ((((X . 1) . 1) . -1) . 1))

Here you see the common domain factor 2 and the two factors x + 1 and x- 1 as standard forms paired with their multiplicity 1.