#15060: The empty graph once again
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Reporter: darij | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-5.12
Component: combinatorics | Resolution:
Keywords: graphs, border cases, bitset, | Merged in:
memleak | Reviewers:
Authors: | Work issues:
Report Upstream: N/A | Commit:
Branch: | Stopgaps:
Dependencies: |
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Comment (by darij):
I noticed the issue when I tried to compute the chromatic polynomial of an
empty graph and got a wrong answer with #14529 applied (and an error
without). It starts by checking whether the graph is connected and if not,
multiplying the characteristic polynomials of the connected components. I
claim that most of the time, connectedness appears together with connected
components, and from the viewpoint of connected components it is much more
natural to have empty objects disconnected.
If you are saying it's theology, can't we rather output an error instead
of claiming it is "True"?
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Ticket URL: <http://trac.sagemath.org/ticket/15060#comment:3>
Sage <http://www.sagemath.org>
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