On 10/12/07, Joel B. Mohler <[EMAIL PROTECTED]> wrote: > > I find the two following results contradictory: > > sage: FractionField(ZZ) is QQ > True > sage: is_FractionField(QQ) > False > > Is that a bug?
No. all of the many dozens of is_* methods do *type* checking. They are not checking some abstract mathematical properties. There is a specific data type in Sage for abstract FractionFields and is_FractionField tests if something is of that type. If it just tested whether a field was a fraction field in some abstract mathematical sense, it would be a useless function, since all fields are fraction fields of themselves. William -- William Stein Associate Professor of Mathematics University of Washington http://wstein.org --~--~---------~--~----~------------~-------~--~----~ 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/ -~----------~----~----~----~------~----~------~--~---
