Ralf Hemmecke wrote: > > Shouldn't we clean up a bit? > > We have the category AbelianMonoidRing and also there is > MonoidRingCategory. Shouldn't at least one be a subcategory of the other? > > http://fricas.github.io/api/AbelianMonoidRing > http://fricas.github.io/api/MonoidRingCategory
Well, this is another instance of 'monoid problem': AbelianMonoidRing uses AbelianMonoid as exponents, that is uses '+' for exponent arithmetic. MonoidRingCategory uses Monoid, that is '*'... > Additionally, the docstring for AbelianMonoidRing says: > > """ > The monomials commute with each other, but in general do not commute > with the coefficients (which themselves may or may not be commutative). > """ > > That sounds as if it were allowed that one could use a non-commutative > coefficient domain. But according to the types the coefficient domain is > an AbelianMonoid. Which means that '+' for coefficients is commutative. But we do not require commutative '*'. > What makes the whole stuff confusing, is that there is a domain MonoidRing > > http://fricas.github.io/api/MonoidRing > > Opinions? ATM we have to live with this. I would like to allow operation names as parameters for constructors which would lead to single Monoid and cut some resulting duplication. But to do this correctly we need first to fix several other bugs/limitations in Spad compiler. > I tend to avoid the word "Category" for known mathematical structures. > Like Ring, MonoidRing should be the name of a category. Unfortunately, I > wouldn't have a replacement name for what is currently called MonoidRing > in FriCAS. Considering 'Category' as part of name, I think it is quite reasonable. There are several cases where the same name would be appropriate both for category and for domain and IMO adding 'Category' suffix to category is the least confusing solution. -- Waldek Hebisch -- 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 https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.
