Surely all Ralf meant was that R[X] is a subring of R[[X]], i.e. some elements of R[[X]] are exact, just as some decimal numbers like 0.25 are exact (in binary), and just as we might want to define a real number as having *exactly* the value 0.25 and not just 0.25 + O(10^-1000) one might want to consider 1+X as an exact power series and not just 1+X+O(X^1000).
Of course I amy have misunderstood Ralf (or you)! John On 22 January 2014 11:49, Ralf Stephan <gtrw...@gmail.com> wrote: > While the ring type hierarchy does not reflect that polynomials are power > series, you can have a power series without bigoh which is pratically a > polynomial but, being a power series, has much less member functions > available. > > I think Sage shouldn't allow a zero bigoh term in power series. It should > avoid unexpected behaviour, eg. users complaining that a polynomial isn't > what it seems. > > But I'm writing here to ask for your opinion before I think about patching, > because I'm only beginning to understand Sage, and I'm not even a > mathematician! > > Regards, > Ralf Stephan > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
