On 9/5/07, Joel B. Mohler <[EMAIL PROTECTED]> wrote: \> Yes, so I found FreeMonoid after sending my first e-mail and was testing it > out. I think I may have found something that is not implemented: > > sage: a=FreeMonoid(1,'a').0 > sage: a*a > a^2 > sage: a.substitute(5) > a # should be 5? > sage: a.substitute(a=5) > a # should be 5? > > I would have expected those last two results to be 5 -- am I missing > something?
The whole "substitute" architecture was implemented in SAGE long after monoids were implemented. So you'll have to implement monoid substitution and send me a patch. I made a trac ticket for you: http://www.sagemath.org:9002/sage_trac/ticket/598 > I guess substituting isn't an entirely common operation for free > monoids, but it seems to be a sensibly defined operation. Then again, maybe > not: > > sage: M.<x,y> = FreeMonoid(2) > sage: (x*y).substitute(x=1) > x*y # I would think that this is 1*y > > I find that result unsatisfactory as well, but I sure don't have a good idea > about what ring (?) the result '1*y' would be a part of. Just do the arithmetic. All monoids have a 1 by definition, so 1*y is just "y" in that monoid. William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@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-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
