2021/09/27 by Benjamin J. Clark, Clark, Benjamin J., Pietro Paparella +1
Mathematics · #Complex Variables (math.CV) #FOS: Mathematics #Rings and Algebras (math.RA) #math.CV #math.RA
paper · pdf · doi:10.48550/arxiv.2109.13365
To appear in Mathematics Exchange
arxiv created 2022/04/29 · arxiv updated 2022/05/03
A known characterization for entire functions that preserve all nonnegative matrices of order two is shown to characterize polynomials that preserve nonnegative matrices of order two. Equivalent conditions are derived and used to prove that \mathscrP3 ⊂ \mathscrP2, which was previously unknown. A new characterization is given for polynomials that preserve nonnegative circulant matrices of order two.