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math1um / objects-invariants-properties

Objects, Invariants and Properties for Graph Theory (GT) automated conjecturing: in particular with the Sage program CONJECTURING: http://nvcleemp.github.io/conjecturing/
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Change name of graph fork and add has_fork to list #582

Closed yirkajk closed 6 years ago

yirkajk commented 6 years ago

The graph fork is poorly named, since there's a function with that name. And, depending when things are loaded, fork doesn't reference the graph.

The functions has_fork and is_fork_free are not included in any list of properties. They probably don't have any precomputed values either.

math1um commented 6 years ago

This is the star graph S_{1,1,3}

It almost certainly has another standard name. That would be useful.

It can be found at: http://www.graphclasses.org/smallgraphs.html#X172

HOG says: "Graph with canonical form 'E?NO'

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yirkajk commented 6 years ago

Closing this issue. NOTE: No values will have been precomputed for has_fork or is_fork_free as part of Issue #551. We branched precomputing off prior to this commit.

math1um commented 6 years ago

hi,

the chair has order 5, while the "fork" (i must have seen this in the literature) has order 6. we settled on Star_1_1_3 (the name on the Graph Classes website.

this graph is also the "killer" and the "milkbone"

:)

c

On Thu, Jul 12, 2018 at 1:10 PM, thenealon notifications@github.com wrote:

I understand this issue is closed, so ignore this. But for posterity, I have always known this graph as the chair.

[image: screen shot 2018-07-12 at 1 08 17 pm] https://user-images.githubusercontent.com/3923139/42648439-efe59e4c-85d4-11e8-8fa7-628caf72cf31.png

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