3 papers
math.SP2026
On a conjecture concerning totally extremal ideal Perron similarities
Erica J. Artemis, Pietro Paparella
Identifying ideal Perron similarities is a problem of central interest in the longstanding nonnegative inverse eigenvalue problem (NIEP). A normalized ideal Perron similarity is ca…
math.SP2025
Character tables are ideal Perron similarities
David Z. Gershnik, Alexander J. Lewis, Pietro Paparella
An invertible matrix is called a Perron similarity if it diagonalizes an irreducible, nonnegative matrix. Each Perron similarity gives a nontrivial polyhedral cone, called the spec…
math.RA2024
Polynomials that preserve nonnegative monomial matrices
Benjamin J. Clark, Pietro Paparella
A recently-established necessary condition for polynomials that preserve the class of entrywise nonnegative matrices of a fixed order is shown to be necessary and sufficient for th…