#17316: RegularMatroid.is_isomorphic returns false positives
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Reporter: Stefan | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.4
Component: matroid theory | Keywords: matroid, isomorphism
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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Example:
{{{
from sage.matroids.advanced import *
Mnew = RegularMatroid(groundset=range(12), matrix=Matrix(ZZ,
[[ 1, 0, 0, 0, 1, 0, 0,-1,-1, 0, 1, 0],
[ 0, 1, 0, 0,-1, 1, 0, 0, 0, 0, 0, 0],
[ 0, 0, 1, 0, 0,-1, 1, 0, 1, 0,-1, 0],
[ 0, 0, 0, 1, 0, 0,-1, 1, 0, 0, 0, 0],
[ 0, 0, 0, 0, 0, 1,-1, 0, 0, 1, 1, 0],
[ 0, 0, 0, 0, 1, 0, 0,-1,-1, 0, 0, 1]]))
Nnew = RegularMatroid(groundset=range(12), matrix=Matrix(ZZ,
[[1,0,0,0,0,0,1,1,0,0,1,0],
[0,1,0,0,0,0,1,0,1,0,1,0],
[0,0,1,0,0,0,1,0,0,1,1,0],
[0,0,0,1,0,0,1,1,0,0,0,1],
[0,0,0,0,1,0,1,0,1,0,0,1],
[0,0,0,0,0,1,1,0,0,1,0,1]]))
print Mnew.is_isomorphic(Nnew)
print len(Mnew.circuits()) == len(Nnew.circuits())
}}}
{{{
True
False
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/17316>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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