On 02/27/2010 01:41 PM, Rob Beezer wrote:
On Feb 27, 6:37 am, David Joyner<wdjoy...@gmail.com> wrote:
There are several places where bipartite graphs
differ (at least in the literature) from regular graphs.
For example, usually the bipartite graph's adjacency matrix
is not square.
I think an "adjacency matrix" should always be square. But for a
bipartite graph if you order the vertices consecutively within the two
parts of the bipartition, then you get a block matrix with zero
matrices in the northwest and southeast corners. And the other two
corners are transposes of each other (but not square when the
bipartite sets are different sizes).
This is in the BipartiteGraph class as "reduced_adjacency_matrix()."
I can't recall ever seeing this matrix given a name, so I don't know
if this is how one would expect to find it. In the research for your
graph theory book have you learned what others call it?
There was some discussion several years ago about what this should be
called. I believe this term came from Richard Brualdi's combinatorial
matrix theory book (I remember running down the hall to my advisor's
office to look it up! :), but my memory may be inaccurate.
Thanks,
Jason
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