The chordless cycle polynomial of a graph may be defined as
where
is the number of chordless cycles (of length at
least four) and
is the length of a longest chordless
cycle.
Precomputed chordless cycles of many graphs are implemented in the Wolfram Language as GraphData[g, "ChordlessCyclePolynomial"][x].
If
is a bipartite graph, then
contains only even powers
of
because the length of every graph cycle in
is an even number. By König's
line coloring theorem, the same conclusion holds when
has a bipartite graph as
its root graph, even though
need not itself be a bipartite
graph. In this case every chordless cycle
of length at least 4 comes from a graph cycle in the
root graph, while triangles
in
are not counted by
. Consequently, the odd part
of
is 0 for both bipartite graphs and line
graphs of bipartite graphs.