20bits - Latest Comments in Graph Theory: Part II (Linear Algebra) | 20bits

Re: Graph Theory: Part II (Linear Algebra) | 20bits

Carlos — Wed, 18 Feb 2009 07:32:39 -0000

When the part iii is coming up?

Re: Graph Theory: Part II (Linear Algebra) | 20bits

Kundai — Thu, 09 Oct 2008 00:48:52 -0000

For "4. Vector addition distributes over scalar multiplication",
should that not read that "Scalar multiplication distributes over vector addition?"

Re: Graph Theory: Part II (Linear Algebra) | 20bits

Jesse — Tue, 06 Nov 2007 14:15:20 -0000

Dan,

You're right, but it'd be a pain in the butt to go back and correct it. The error will have to stand.

Re: Graph Theory: Part II (Linear Algebra) | 20bits

Dan — Wed, 03 Oct 2007 10:58:52 -0000

That adjacency matrix seems to be wrong.

Look at row 1. It indicates that vertex 1 is connected to vertices 2 and 4. When in fact it is connected to vertices 2 and 3.

If the graph had vertices in clockwise order v1, v2, v3, v4 as James suggests, then this adjacency matrix would be correct.

Enjoying reading your blog very much and looking forward to the next part in this series!!

Re: Graph Theory: Part II (Linear Algebra) | 20bits

James — Mon, 03 Sep 2007 18:52:18 -0000

Interesting stuff. I had read about incidence matricies before, but hadn't seen a graph theory representation. By the way, I think there's an inconsistancy between your definition of the incidence matrix and the incidence matrix for C4 (did you mean m verticies and n columns, where the matrix is mxn?) Your graph of C4 also has the bottom two verticies interchanged.