  The CHY construction naturally associates a vector in $\mathbb{R}^{(n-3)!}$
to every 2-regular graph with $n$ vertices. Partial amplitudes in the biadjoint
scalar theory are given by the inner product of vectors associated with a pair
of cycles. In this work we study the problem of extending the computation to
pairs of arbitrary 2-regular graphs. This requires the construction of
compatible cycles, i.e. cycles such that their union with a 2-regular graph
admits a Hamiltonian decomposition. We prove that there are at least $(n-2)!/4$
such cycles for any 2-regular graph. We also find a connection to breakpoint
graphs when the graph only has double edges. We end with a comparison of the
lower bound on the number of randomly selected cycles needed to generate a
basis of $\mathbb{R}^{(n-3)!}$, using the super Catalan numbers, and our lower
bound for compatible cycles.
