[GAP Forum] Composition of polynomials

[Anvita]

Dear Forum,

Suppose that f1,...fn are polynomials in x1,...,xk
and suppose that f is another such polynomial that
can be represented in the form

f = g(f1,...,fn)

where g(y1,...,yn) is a new polynomial. Can I use GAP
to find the polynomial g? For example, expressing a
symmetric polynomial as a polynomial in the elementary
symmetric  polynomials is a particular case of this problem.

Thank you,
Anvita