#12243: Girth of a graph fails for non-integer vertices
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Reporter: rbeezer | Owner: jason, ncohen, rlm
Type: defect | Status: positive_review
Priority: minor | Milestone: sage-4.8
Component: graph theory | Keywords:
Work_issues: | Upstream: N/A
Reviewer: Nathann Cohen | Author: Rob Beezer
Merged: | Dependencies:
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Comment(by dimpase):
Replying to [comment:8 rbeezer]:
> Replying to [comment:4 ncohen]:
> > Do you use the girth function much ? I'm randomly finding out that
people around use Graph functions I wouldn't expect them to, and it's a
pity otherwise I would know which kind of things should be reimplemented
more efficiently first !
>
> I am teaching a course on algebraic graph theory here at AIMS in South
Africa. So one of the topics is Moore graphs and cages, where girth is
one of the characterizing properties. I'd like the students to be able to
determine girth (by-hand) for things like the Odd Graph. Thus, having
Sage to help with this is very useful.
one can rely on GAP's package GRAPE for this (ideally, it should even be
possible to write a backend based on it).
I showed a bit of this on #9136, constructing the Schlaefli graph.
Dima
>
> You are right - I tend to take these highly symmetric graphs as-built
and explore their properties, not so much manipulating them. Especially
when teaching. So having them "read-only" would meet many of my purposes.
And Dima's idea to carry more group-theoretic information is a good one,
though it seems a big job to figure out how to do that "right" and then
exploit it consistently.
One idea might be a GRAPE-based graph backend.
>
> Rob
>
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12243#comment:9>
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