#11526: count_points() error for generic schemes. (includes patch)
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Reporter: mmarco | Owner: AlexGhitza
Type: defect | Status: new
Priority: major | Milestone: sage-4.7.1
Component: algebraic geometry | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author: Miguel Marco
Merged: | Dependencies:
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sage raises an error when trying to count the number of points of a
subscheme of an affine scheme.
See, for instance:
sage: F=FiniteField(3)
sage: R.<x,y>=F[]
sage: A=AffineSpace(F,2)
sage: I=R.ideal(x^2-y^2-1)
sage: S=A.subscheme(I)
sage: S.count_points(2)
---------------------------------------------------------------------------
NameError Traceback (most recent call
last)
/home/mmarco/sage-4.6.2/<ipython console> in <module>()
/usr/lib64/python2.7/site-packages/sage/schemes/generic/scheme.py in
count_points(self, n)
531 F1 = GF(q**i, name='z')
532 S1 = self.base_extend(F1)
--> 533 a.append(len(S1.rational_points()))
534 return(a)
535
/usr/lib64/python2.7/site-
packages/sage/schemes/generic/algebraic_scheme.py in rational_points(self,
F, bound)
1129 raise TypeError, "Unable to enumerate points over
%s."%F
1130 try:
-> 1131 return X.points()
1132 except TypeError:
1133 raise TypeError, "Unable to enumerate points over
%s."%F
/usr/lib64/python2.7/site-packages/sage/schemes/generic/homset.py in
points(self, B)
162 except TypeError:
163 raise TypeError, "Domain of argument must be of the
form Spec(S)."
--> 164 if is_RationalField(R) or R == Z:
165 if not B > 0:
166 raise TypeError, "A positive bound B (= %s) must
be specified."%B
NameError: global name 'Z' is not defined
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11526>
Sage <http://www.sagemath.org>
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