#16381: primary decomposition doesn't work when ideal is in a quotient
polynomial
ring
-----------------------------------+----------------------------
Reporter: was | Owner: malb
Type: defect | Status: new
Priority: minor | Milestone: sage-6.3
Component: commutative algebra | Keywords:
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
-----------------------------------+----------------------------
I was trying to do a simple example on page 51 of Atiyah-Macdonald using
Sage, and it fails:
{{{
R.<x,y,z> = QQ[]
I = R.ideal([x*y - z^2])
A.<xbar,ybar,zbar> = R.quotient(I)
p = A.ideal([x,z])
p.primary_decomposition()
}}}
boom! ---
{{{
Error in lines 5-5
Traceback (most recent call last):
File "/projects/71755b5a-fde1-45bc-
9ca8-d06d5b9749f1/.sagemathcloud/sage_server.py", line 733, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
File "", line 1, in <module>
File "/usr/local/sage/sage-6.2.rc0/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 604, in
__call__
return self.f(self._instance, *args, **kwds)
File "/usr/local/sage/sage-6.2.rc0/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 1146, in
primary_decomposition
return [I for I, _ in self.complete_primary_decomposition(algorithm)]
File "/usr/local/sage/sage-6.2.rc0/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 604, in
__call__
return self.f(self._instance, *args, **kwds)
File "/usr/local/sage/sage-6.2.rc0/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 505, in
wrapper
return func(*args, **kwds)
File "/usr/local/sage/sage-6.2.rc0/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 1068, in
complete_primary_decomposition
P = primdecSY(self)
File "function.pyx", line 1285, in
sage.libs.singular.function.SingularFunction.__call__
(sage/libs/singular/function.cpp:13025)
TypeError: Cannot call Singular function 'primdecSY' with ring parameter
of type '<class
'sage.rings.quotient_ring.QuotientRing_generic_with_category'>'
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/16381>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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