#15061: Pari can't handle all polynomial resultants
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Reporter: robharron | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-5.12
Component: algebra | Keywords: pari, resultant, sylvester
Merged in: | matrix
Reviewers: | Authors:
Work issues: | Report Upstream: N/A
Commit: | Branch:
Stopgaps: | Dependencies:
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Consider the following:
{{{
sage: R.<T> = PowerSeriesRing(QQ)
sage: F = R([1,1],2)
sage: F
1 + T + O(T^2)
sage: RP.<x> = PolynomialRing(R)
sage: P = x^2 - F
sage: P.resultant(P.derivative())
ValueError: series precision must be finite for conversion to pari object.
}}}
In particular, sage is incapable of computing the discriminant of this
*quadratic* polynomial! I'll shortly post a patch that catches this error
and uses the sylvester matrix instead.
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Ticket URL: <http://trac.sagemath.org/ticket/15061>
Sage <http://www.sagemath.org>
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