2009/08/03 by Joseph P. S. Kung, Gordon F. Royle, Kung, Joseph P. S. +1 · 1 citation
Mathematics · #05B35 #Combinatorics (math.CO) #FOS: Mathematics #math.CO #msc:05B35
paper · pdf · doi:10.48550/arxiv.0908.0181
12 pages, 1 figure
arxiv created 2009/09/11 · arxiv updated 2009/12/01
We show if the flow polynomial of a bridgeless graph G has only integral roots, then G is the dual graph to a planar chordal graph. We also show that for 3-connected cubic graphs, the same conclusion holds under the weaker hypothesis that it has only real flow roots. Expressed in the language of matroid theory, this result says that the cographic matroids with only integral characteristic roots are the cycle matroids of planar chordal graphs.