[SeqFan]. Adjacency matrix, correction^2.

[Gordon Royle]

>
> As Matthew Conroy kindly corrected me, it _is_ mentioned there,  
> right in the properties section:
>  "If /A/ is the adjacency matrix of the directed or undirected  
> graph /G/, then the matrix /A/^/n/
>  (i.e. the matrix product of /n/ copies of /A/) has an interesting  
> interpretation: the entry in
>  row /i/ and column /j/ gives the number of (directed or  
> undirected) paths of length /n/ from
>  vertex /i/ to vertex /j/."

One comment about this description is that the word "path" here is  
being used for what are normally called "walks" - the distinction is  
that walks can use vertices and edges more than once, while paths are  
normally defined to forbid repeated vertices.

Gordon