math.RA — Rings and Algebras
Spectrally Simple Spectra without Irreducible Nonnegative Realizations
We give a counterexample to a conjecture of Johnson, Marijuán, and Pisonero: we show that the spectrum is realizable and spectrally simple, but has no irreducible nonnegative realization. More generally, we prove their nonexistence conjecture for an order-four boundary family.
A mix of human-written and AI-generated textHuman understanding: all partsIrreducible matricesIrreducible realizationNonnegative inverse eigenvalue problemPerron rootSpectrally simple spectrumnonnegative matrices