MathCastle
Graph TheorySuperchallengeDirected Graphs and Network Flows

Directed Graphs and Network Flows · Superchallenge problem

A graph has vertices 1,…,51,\dots,5 and edges 12,23,34,45,51,13,2412,23,34,45,51,13,24 (a 55-cycle with two crossing chords). How many of the 27=1282^7=128 ways to orient its seven edges give a strongly connected digraph?