3 papers
math.CO2026
A strong nullity parameter for rooted graphs
Aida Abiad, Mary Flagg, H. Tracy Hall +2
The inverse eigenvalue problem of a graph studies the possible spectra of matrices associated with , including as an important subproblem the possible nullities of such a ma…
math.CO2025
Zero forcing propagation time intervals and graphs with fixed propagation time
Daniela Ferrero, H. Tracy Hall, Leslie Hogben +2
Zero forcing in a graph refers to the evolution of vertex states under repeated application of a color change rule. Typically the states are chosen to be blue and white, and a forc…
math.CO2025
A combinatorial bound on the number of distinct eigenvalues of a graph
Sarah Allred, Craig Erickson, Kevin Grace +2
The smallest possible number of distinct eigenvalues of a graph , denoted by , has a combinatorial bound in terms of unique shortest paths in the graph. In particular, $q(…