3 papers
math.CO2026
Pendant paths and integral generalized sun graphs
Rodrigo O. Braga, Jean Carlo Moraes, Matheus C. Santos
A graph is integral if the spectrum of its adjacency matrix consists entirely of integers. We prove that every simple graph having a pendant path with at least three edges has an e…
math.CO2023
Diminimal families of arbitrary diameter
Luiz Emilio Allem, Rodrigo Orsini Braga, Carlos Hoppen +3
Given a tree , let be the minimum number of distinct eigenvalues in a symmetric matrix whose underlying graph is . It is well known that , where $d(T)…
math.CO2020
Graphs with at most two nonzero distinct absolute eigenvalues
N. E. Arévalo, R. O. Braga, V. M. Rodrigues
In his survey "Beyond graph energy: Norms of graphs and matrices" (2016), Nikiforov proposed two problems concerning characterizing the graphs that attain equality in a lower bound…