On Wed, May 14, 2008 at 9:25 AM, Carl Witty <[EMAIL PROTECTED]> wrote: > > On May 14, 7:17 am, "William Stein" <[EMAIL PROTECTED]> wrote: >> So 1+1 = 1 and 1*1 = 1 and 1*0 = 0 and 1+0 = 1 and 0+0=0? >> That's *not* a ring, so you shouldn't make matrices over it in >> Sage, since in Sage all matrices are over rings. > > Once #2519 (lattices in the poset sense) is merged, I was going to > suggest modifying Sage matrices to support lattices as well as rings. > (The booleans are a lattice). This might end up being totally new > code, since most current Sage matrix operations are meaningless on > matrices over lattices; but matrix addition and multiplication are > well-defined.
Interesting and potentially useful. I'm looking forward to hearing more. By the way, a few days ago Ralf posted this: "There are also some further points about coercion in http://axiom-portal.newsynthesis.org/refs/articles/doye-aldor-phd.pdf"; Amusingly, on page 26 of that Ph.D. thesis it says (in reference to Maple): "It is ridiculous that one may create matrices over any type which does not form a ring! [...] Martin points out that Axiom allows Matrix(Float) as a type yet the Float type does not really form a ring." I'm amused by a thesis that claims that computing with "matrices" that have floating point entries is ridiculous. :-) -- William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
