72 citations · 248 across the 29 of their papers we have counts for
5 papers · 1 filter
Colouring the normalized Laplacian
Gabriel Coutinho, Rafael Grandsire, Célio Passos
We apply Cauchy's interlacing theorem to derive some eigenvalue bounds to the chromatic number using the normalized Laplacian matrix, including a combinatorial characterization of…
Algebras, graphs and thetas
Marcel K. de Carli Silva, Gabriel Coutinho, Chris Godsil +1
We extend the clique-coclique inequality, previously known to hold for graphs in association schemes and vertex-transitive graphs, to graphs in homogeneous coherent configurations…
Dual Hoffman Bounds for the Stability and Chromatic Numbers Based on SDP
Nathan Benedetto Proença, Marcel K. de Carli Silva, Gabriel Coutinho
The notion of duality is a key element in understanding the interplay between the stability and chromatic numbers of a graph. This notion is a central aspect in the celebrated theo…
Fractional Revival and Association Schemes
Ada Chan, Gabriel Coutinho, Christino Tamon +2
Fractional revival occurs between two vertices in a graph if a continuous-time quantum walk unitarily maps the characteristic vector of one vertex to a superposition of the charact…
Perfect State Transfer in a Spin Chain without Mirror Symmetry
Gabriel Coutinho, Luc Vinet, Hanmeng Zhan +1
We introduce an analytical spin chain with asymmetrical transport properties. It has an even number of sites labeled by . It does not exhibit perfect state…