TITLE: Expressing a symmetric polynomial in terms of elementary symmetric polynomials using computer?
QUESTION [15 upvotes]: Are there any computer algebra systems with the functionality to allow me to enter in an explicit symmetric polynomial and have it return that polynomial in terms of the elementary symmetric polynomials? Can I do this in sage? How do I do it? Thank you.

REPLY [4 votes]: In Sage, if $p$ is the polynomial to convert
Sym = SymmetricFunction(QQ)
e = Sym.elementary()
f = Sym.from_polynomial(p)
e(f)