The convert( p, 'elsymfun' ) command converts the input polynomial to an expression in terms of the elementary symmetric functions.

If the input polynomial is not symmetric, then an exception is raised.

$\mathrm{convert}\left(x^3+y^3+z^3\,'\mathrm{elsymfun}'\right)$

${\left(x+y+z\right)}^3-3\left(x+y+z\right)\left(xy+xz+yz\right)+3xyz$

$\mathrm{convert}\left({\left(x+y\right)}^2+{\left(x+z\right)}^2+{\left(z+y\right)}^2\,'\mathrm{elsymfun}'\right)$

$2{\left(x+y+z\right)}^2-2xy-2xz-2yz$

$\mathrm{convert}\left(x-y\,'\mathrm{elsymfun}'\right)$

Error, (in `convert/elsymfun`) polynomial is not symmetric