On 13 October 2014 08:27, Waldek Hebisch <[email protected]> wrote: >> > ... >> > It make sense to omit variable names in some cases, for example >> > SparseUnivariatePolynomial gets a lot of use. But in general names >> > are important for readability and FriCAS tries to follow traditional >> > notation. So we should support names.
> Ralf Hemmecke wrote: >> ... >> And I rather think we should have two levels of such domains. The lower >> level should basically work without variables and implement all the >> features. Then there could be a small wrapper domain that would serve >> as an interface to the end user. Programming should still be done with >> the low-level domain. >> Ralf, could you explain what advantages you see or what you would like to achieve by working without variables? I can see the utility of not having to be concerned with names in the case of univariate polynomials but if there is more than one variable then it seems to me that there is no natural choice of canonical isomorphism. For example if we have two polynomials each with two unnamed "variables", why should we prefer to associate the first "variable" of one polynomial with the first "variable" of another, instead of the first of one with the second of the other etc. Using named variables seems like a simple way to provide such an isomorphism. FriCAS already includes domains such as SparseMultivariatePolynomial which do not require the use of List Symbol. In this case the indices for the IndexedExponents domain may come from any domain of category OrderedSet. We could arrange that the indices come from a (0- or 1-based) interval of the Integers but the utility of this does not seem obvious to me. Bill. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.
