[A058387] Series-Parallel Confusion

[Brendan McKay]

The literature has a number of different definitions of
"series-parallel network.  Sometimes multiple sources
and sinks are permitted.

Brendan.


* N. J. A. Sloane <njas at research.att.com> [021108 13:35]:
> a 3-star is no a series-parallel network
> 
> the definition is that o is a s.p. n/w
> and so are all networks that can be obtained by putting 2 of them in series or in parallel
> 
> they all have two terminal nodes (which coicide in the case of o)
> and you put two in series or parallel by doing the obvious things
> to the terminbal nodes
> 
> Neil