I got an odd error when I tried some Groebner basis computations over
a function field. The "lift" command that should give coordinates of
an element of an ideal in terms of a basis gives me an error when it
shouldn't. Here's an example:
sage: K = FractionField(QQ['b','c'])
sage: R.<x,y,z> = PolynomialRing(K,3)
sage: f = y^2*z-4*x^3-K.gens()[0]*x*z^2-K.gens()[1]*z^3
sage: g = x*z^2-f.jacobian_ideal().reduce(x*z^2)
sage: g
x*z^2 + 3*c/(2*b)*z^3
sage: g.lift(f.jacobian_ideal())
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/jacobml/.sage/sage_notebook/worksheets/admin/66/code/
13.py", line 6, in <module>
g.lift(f.jacobian_ideal())
File "/usr/local/sage/local/lib/python2.5/site-packages/
SQLAlchemy-0.4.6-py2.5.egg/", line 1, in <module>
File "/usr/local/sage/local/lib/python2.5/site-packages/sage/rings/
polynomial/multi_polynomial_element.py", line 1441, in lift
raise ArithmeticError, "f is not in I"
ArithmeticError: f is not in I
sage: f.jacobian_ideal().reduce(g)
verbose 0 (2236: multi_polynomial_ideal.py, groebner_basis) Warning:
falling back to very slow toy implementation.
0
Also, perhaps on a related note, the parameters b and d seem to be
defined in an odd way: sage calls K.gens()[0] b, but doesn't recognize
b as input:
sage: K.gens()[0]
b
sage: b
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/jacobml/.sage/sage_notebook/worksheets/admin/66/code/
23.py", line 6, in <module>
b
File "/usr/local/sage/local/lib/python2.5/site-packages/
SQLAlchemy-0.4.6-py2.5.egg/", line 1, in <module>
NameError: name 'b' is not defined
Any help would be appreciated,
Jacob
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to [email protected]
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
-~----------~----~----~----~------~----~------~--~---
