totally nonnegative matrices, totally positive matrices, partial matrix, matrix completion problem, cycles
In earlier work, the labelled graphs G for which every combinatorially symmetric totally nonnegative matrix, the graph of whose specified entries is G, has a totally nonnegative completion were identified. For other graphs, additional conditions on the specified data must hold. Here, necessary and sufficient conditions on the specified data, when G is a cycle, are given for both the totally nonnegative and the totally positive completion problems.
Electronic Journal of Linear Algebra