RT info:eu-repo/semantics/article T1 On universal realizability of spectra A1 Julio, Ana I. A1 Marijuán López, Carlos A1 Pisonero Pérez, Miriam A1 Soto, Ricardo L. K1 Nonnegative matrices K1 Matrices no negativas K1 Eigenvalue problem K1 Problema de valor propio AB A list Λ = {λ1, λ2, . . . , λn} of complex numbers is said to be realizable if it is the spectrum of an entrywise nonnegative matrix. The listΛ is said to be universally realizable (UR) if it is the spectrum of anonnegative matrix for each possible Jordan canonical form allowed byΛ. It is well known that an n × n nonnegative matrix A is co-spectralto a nonnegative matrix B with constant row sums. In this paper, weextend the co-spectrality between A and B to a similarity between Aand B, when the Perron eigenvalue is simple. We also show that ifǫ ≥ 0 and Λ = {λ1, λ2, . . . , λn} is UR, then {λ1 + ǫ, λ2, . . . , λn} is alsoUR. We give counter-examples for the cases: Λ = {λ1, λ2, . . . , λn}is UR implies {λ1 + ǫ, λ2 − ǫ, λ3, . . . , λn} is UR, and Λ1,Λ2 are URimplies Λ1 ∪ Λ2 is UR. PB Elsevier SN 0024-3795 YR 2019 FD 2019 LK http://uvadoc.uva.es/handle/10324/35977 UL http://uvadoc.uva.es/handle/10324/35977 LA eng NO Linear Algebra and its Applications, 2019, vol. 563. p. 353-372 NO Producción Científica DS UVaDOC RD 23-abr-2024