interesting graph theory question from Warren Smith

[Brendan McKay]

* N. J. A. Sloane <njas at research.att.com> [060830 05:52]:
> Max,  maybe the question would be better phrased in terms
> of tournaments - complete directed graphs,
> but only one arrow joining any two nodes.
> Neil

This is the "minimum feedback arc set" problem. Doing a search on
"feedback arc" and "tournament" finds quite a lot of papers. I have
not tried to determine if any of them discuss this particular question.

Brendan.