(2003) Choi, Ji Young; Dealba, Luz Maria; Hogben, Leslie; Kivunge, Benard M; Nordstrom, Sandra K; Shedenhelm, Mike
In this paperthe nonnegative
P
0
-matrix completion problem is considered. It is
shown that a pattern for 4
×
4 matrices that includes all diagonal positions has nonnegative
P
0
-
completion if and only if its digraph is complete when it has a 4-cycle. It is also shown that any
positionally symmetric pattern that includes all diagonal positions and whose graph is an
n
-cycle
has nonnegative
P
0
-completion if and only if
n
=4.