Opened 5 years ago
Last modified 16 months ago
#17251 closed defect
Incomplete multivariate factorization — at Version 3
Reported by: | jdemeyer | Owned by: | |
---|---|---|---|
Priority: | critical | Milestone: | sage-8.2 |
Component: | factorization | Keywords: | singular |
Cc: | jakobkroeker | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | Completely fixed; Fix reported upstream | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
With sage-6.4.beta6, the following polynomial factorization gives a reducible factor (-a^2 + b^2)
:
sage: R.<z,a,b> = PolynomialRing(QQ) sage: N = -a^4*z^8 + 2*a^2*b^2*z^8 - b^4*z^8 - 16*a^3*b*z^7 + 16*a*b^3*z^7 + 28*a^4*z^6 - 56*a^2*b^2*z^6 + 28*b^4*z^6 + 112*a^3*b*z^5 - 112*a*b^3*z^5 - 70*a^4*z^4 + 140*a^2*b^2*z^4 - 70*b^4*z^4 - 112*a^3*b*z^3 + 112*a*b^3*z^3 + 28*a^4*z^2 - 56*a^2*b^2*z^2 + 28*b^4*z^2 + 16*a^3*b*z - 16*a*b^3*z - a^4 + 2*a^2*b^2 - b^4 sage: N.factor() (-1) * (-a^2 + b^2) * (-z^4*a + z^4*b - 4*z^3*a - 4*z^3*b + 6*z^2*a - 6*z^2*b + 4*z*a + 4*z*b - a + b) * (z^4*a + z^4*b - 4*z^3*a + 4*z^3*b - 6*z^2*a - 6*z^2*b + 4*z*a - 4*z*b + a + b)
This is fixed by #17254.
Change History (3)
comment:1 Changed 5 years ago by
- Keywords singular added
comment:2 Changed 5 years ago by
- Description modified (diff)
comment:3 Changed 5 years ago by
- Description modified (diff)
- Report Upstream changed from N/A to Completely fixed; Fix reported upstream
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