ELA, Volume 8, pp. 140-157, December 2001, abstract.
Minimal CP rank
Naomi Shaked-Monderer
For every completely positive matrix A, cp-rankA >= rankA.
Let cp-rankG be the maximal cp-rank of a CP matrix realization
of G. Then for every graph G on n vertices, cp-rankG >= n.
In this paper the graphs G on n vertices for which equality
holds in the last inequality, and graphs G such that
cp-rankA = rankA for every CP matrix realization A of G,
are characterized.