["Followup-To:" header set to gmane.comp.mathematics.sage.algebra.] On 2012-08-14, John H Palmieri <jhpalmier...@gmail.com> wrote: > ------=_Part_11_31037299.1344973817229 >> What about just "dual"? By default, it would compute the dual with >> respect to the category to which it belongs, and we can allow >> customization like so: > > >> sage: H.dual(category=VectorSpaces(QQ)) >> ... a vector space ... >> > > I think "H.dual()" is good. Specifying a category like this also, as well as > > sage: VectorSpaces(QQ)(H.dual())
Start with an object O in some category C1, take its dual D in C1, and apply the forgetful functor to map it to a sub-category C2; one would not always get the same result as if one first applies the forgetful functor to O and then dualise the result in C2, right? And hence VectorSpaces(QQ)(H.dual()) might (perhaps not here, but in other situations) be different from (VectorSpaces(QQ)(H)).dual(). Would that be a problem? Anyway, I support the suggestion to have just one method "dual()" that has an optional argument "category" (having self.category() as default). Then it is clear in what category the dual is taken. Cheers, Simon -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To post to this group, send email to sage-combinat-devel@googlegroups.com. To unsubscribe from this group, send email to sage-combinat-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en.
