#16190: Bug in is_square over the reals
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Reporter: pkoprowski | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.2
Component: algebra | Keywords: mathematically wrong answer
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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Try the following:
{{{
R1.<x> = QQ[]
R2 = RR['x']
R3 = RDF['x']
R4 = AA['x']
f = 81*x^10 - 108*x^9 + 216*x^8 - 66*x^7 - 26*x^6 + 138*x^5 - 103*x^4 -
10*x^3 + 31*x^2 - 10*x + 1
print 'QQ:', f.is_square()
print 'RR:', R2(f).is_square()
print 'RDF:', R3(f).is_square()
print 'AA:', R4(f).is_square()
}}}
The polynomial is a square already over the rationals, hence also over
every bigger field. But the is_square method incorrectly returns False
over RR and RDF.
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Ticket URL: <http://trac.sagemath.org/ticket/16190>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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