@article{Brower_Ponomarenko_2020, title={On the Monotonicity of the Number of Positive Entries in Nonnegative Four Element Matrix Powers}, volume={3}, url={https://journals.calstate.edu/pump/article/view/2233}, abstractNote={<p>Let <em>A</em> be a nonnegative square matrix of order <em>m</em> and let <em>F(A</em>) denote the number of positive entries in <em>A</em>. We consider conditions on <em>A</em> to make the sequence <em>{F(A<sup>n</sup>)}<sub>n≥1</sub></em> monotone. This is known for F(A) ≤ 3 and <em>F(A) ≥ m<sup>2</sup>-2m+2</em>; we extend this to <em>F(A)</em>=4.</p>}, journal={The PUMP Journal of Undergraduate Research}, author={Brower, Cole Rubin and Ponomarenko, Vadim}, year={2020}, month={Feb.}, pages={26-36} }