Re: [Axiom-developer] about Expression Integer

[Ralf Hemmecke]

> >        differentiate(p: %,v: OV) ==
> >              multivariate(differentiate(univariate(p,v)),v)
> >
> > where univariate just converts p to an element of
> > SparseUnivariatePolynomial(%). (BTW, that's already a trick!)

> Alternatively, if we are going to allow constructions in which
> the coefficient domain of SUP might contain the polynomial
> variable, then the implementation of 'differentiate' in SUP
> should be corrected.

Look more closely. SUP does not even know of a variable name. So how 
should it do something else than differentiate with respect to the only 
(unamed) variable it has? It's a univariate polynomial in the sense of 
being a function with finite support from the natural numbers to the 
coefficient ring.

Ralf