If a is a multivariate polynomial with integer coefficients, content returns the content of a with respect to x, thus returning the greatest common divisor of the coefficients of a with respect to the indeterminate(s) x.  The indeterminate(s) x can be a name, list, or set of names.

The third argument pp, if present, will be assigned the primitive part of a, namely a divided by the content of a.

If the coefficients of a in x are rational functions then the content computed will be such that the primitive part is a multivariate polynomial over the integers whose content is 1.

Similarly, primpart returns a/content(a, x). The third argument co, if present, will be assigned the content. Note:  Whereas the sign is removed from the content, it is not removed from the primitive part.