On the Arc Reversal Properties of Digraphs without Loops
نویسندگان
چکیده
Let G be a multidigraph without loops. Let l i be the upper bounds for arcs a i ∈ A(G) to be visited by any closed directed walk in G. We prove that there exists a sequence of finite integers {l i } for which every arc (and every parallel number of arcs) reversal in G decreases the number of closed directed walks if and only if every arc belongs to an elementary directed cycle in G.
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