Dear William, On 11/09/2008 09:43 PM, William Stein wrote: > On Sun, Nov 9, 2008 at 7:31 AM, Nicolas M. Thiery > <[EMAIL PROTECTED]> wrote: >> - Are the Sage categories currently used for anything but documenting >> and testing the mathematical properties of parents? > > Yes. Here is an example of one of the main ways I intended > categories to be used in practice.
Similar to what you wrote... sage: C = VectorSpaces(GF(5)) sage: C Category of vector spaces over Finite Field of size 5 sage: W = (ZZ^3).span([[1,2,3],[4,5,3]]) sage: W Free module of degree 3 and rank 2 over Integer Ring Echelon basis matrix: [1 2 3] [0 3 9] sage: C(W) Vector space of degree 3 and dimension 2 over Finite Field of size 5 Basis matrix: [1 0 2] [0 1 3] That looks to me as if C is like a coercion function. Should sage: C(ZZ) actually work? Currently it doesn't. > As you can see, categories are to parents like parents > are to elements... Can you point me to the proper specification of a sage category concept? The only thing I could find up to now is http://www.sagemath.org/doc/ref/module-sage.categories.category.html which is a rather imprecise specification. Ralf --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
