This looks like a bug to I reported it as http://trac.sagemath.org/sage_trac/ticket/3678 As a work-around, maybe you could use the SymbolicExpressionRing?
On Sat, Jul 19, 2008 at 1:02 AM, Andrey Novoseltsev <[EMAIL PROTECTED]> wrote: > > Hello, > > I need to substitute some variable in a polynomial ring with a > fractional power of another one. I know that the result still will be > a polynomial, however I have discovered the following behaviour (v. > 3.0.5 on sage.math): > > sage: pr = PolynomialRing(QQ, "u,v") > sage: pr.injvar() > Defining u, v > sage: u^(1/2) > 1 > sage: pr = PolynomialRing(QQ, "w") > sage: pr.injvar() > Defining w > sage: w^(1/2) > --------------------------------------------------------------------------- > TypeError Traceback (most recent call > last) > > /home/novoselt/<ipython console> in <module>() > > /home/novoselt/polynomial_element.pyx in > sage.rings.polynomial.polynomial_element.Polynomial.__pow__ (sage/ > rings/polynomial/polynomial_element.c:8179)() > > /home/novoselt/element.pyx in > sage.structure.element.RingElement.__mul__ (sage/structure/element.c: > 8814)() > > /home/novoselt/coerce.pyx in > sage.structure.coerce.CoercionModel_cache_maps.bin_op_c (sage/ > structure/coerce.c:5582)() > > TypeError: unsupported operand parent(s) for '*': '<type 'list'>' and > 'Rational Field' > sage: sqrt(w) > sqrt(w) > > Is it how things were supposed to work for some reason or a bug? > > Thank you, > Andrey > > > --~--~---------~--~----~------------~-------~--~----~ 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://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
