[DMANET] A home for graphs

With this mail we want to announce that the website "House of Graphs"
-- http://hog.grinvin.org/ -- is online.

"House of Graphs" hosts lists of graphs (like Snarks, Fullerenes, etc.)
and links to other pages with lists of combinatorial structures (like vertex
transitive graphs, Ramsey graphs, etc.), but its main feature is a searchable
database of graphs that already occurred as counterexamples to
conjectures, as extremal graphs or in other contexts. In short we call
this the
database of "interesting graphs". The key idea is that although already for
small vertex numbers extremely many graphs exist, there are some that
serve again and again as counterexamples and that a database of these
graphs should be established. In this database one can e.g. search for
graphs with certain invariant values, graphs with a certain name
(e.g. Petersen, Balaban, etc.) or graphs that are marked as being
interesting for
a certain invariant (e.g. marked as being interesting for the girth).
These searches can of course also be combined and the results downloaded
so that one gets good candidates for testing new conjectures one is
working on.

Users can add graphs to the database. If the graphs are not yet in the database,
the system computes invariant values for the graphs. So the database can also be used
as a repository. If you discover new interesting graphs, you can make them
available to users by submitting them to the database together with a text
identifier (e.g. counterexample_this_conjecture). Then other scientists
can find and download the graph from "House of Graphs".

More information on "House of Graphs" and its functionalities is given in

Discrete Mathematics, Volume 161, Issues 1-2, Jan. 2013, pages 311-314
Already available online: http://dx.doi.org/10.1016/j.dam.2012.07.018

and

http://arxiv.org/abs/1204.3549

Gunnar Brinkmann, Kris Coolsaet, Jan Goedgebeur and Hadrien Melot





--




Gunnar Brinkmann
Applied Mathematics and Computer Science
Ghent University
Krijgslaan 281 - S9
B - 9000 Ghent

email: Gunnar.Brinkmann@UGent.be

phone: +32-9-264.48.07, Fax: +32-9-264.49.95


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