I didn't really mean "don't implement them" -- just don't do it hastily and be sure you know what you are doing of you do! Of course, everything should be implemented....
John On 16/11/2007, William Stein <[EMAIL PROTECTED]> wrote: > > On Nov 16, 2007 2:07 AM, John Cremona <[EMAIL PROTECTED]> wrote: > > Even before getting to Laurent series, multivariate power series are > > harder to define than you might think, so I would avoid implementing > > them at this point unless you have a specific need for them! You need > > to be really careful since K[[x]][[y]], K[[y]][[x]] and K[[x,y]] are > > not all the same. > > I just want to counter with: Please *do* implement them! Numerous > people involved with Sage have procrastinated implementing > multivariate power series rings more times than I can count at this point. > We need somebody unafraid to just do it. > > William > > > There are probably people on the list more knowledgeable than me about > > this, but I thought it might be worth while posting a warning! > > > > John > > > > On 16/11/2007, David Roe <[EMAIL PROTECTED]> wrote: > > > Hey all, > > > At some point in the near future I may try to bring the implementation of > > > power series rings more into line with the p-adics. The single variable > > > case seems straightforward, but a something popped up for me when thinking > > > about the multivariable case. > > > > > > What is the appropriate analogue of laurent series? Is the key point for > > > laurent series that we allow bounded negative exponents? Or that it's a > > > field? Because allowing bounded negative exponents is not enough to > > > always > > > have inverses: x + y has no inverse if we require the exponents of x and y > > > to be bounded away from negative infinity. > > > David > > > > > > > > > > > > > > > > -- > > John Cremona > > > > > > > > > > > > > -- > William Stein > Associate Professor of Mathematics > University of Washington > http://wstein.org > > > > -- John Cremona --~--~---------~--~----~------------~-------~--~----~ 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://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
