A differential approach for bounding the index of graphs under perturbations

This paper presents bounds for the variation of the spectralradiusλ(G) ofa graphGafter some perturbations or local vertex/edge modifications ofG. Theperturbations considered here are the connection of a new vertex with, say,gverticesofG, the addition of a pendant edge (the previous case withg= 1) an...

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Detalles Bibliográficos
Autores: Dalfó, Cristina, Fiol Mora, Miguel Ángel, Garriga, Ernest
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2011
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10459.1/463240
Acceso en línea:https://doi.org/10.37236/659
https://hdl.handle.net/10459.1/463240
Access Level:acceso abierto
Palabra clave:Graph
Adjacency matrix
Spectral radius
Graph perturbation
Dif-ferential inequalities
Descripción
Sumario:This paper presents bounds for the variation of the spectralradiusλ(G) ofa graphGafter some perturbations or local vertex/edge modifications ofG. Theperturbations considered here are the connection of a new vertex with, say,gverticesofG, the addition of a pendant edge (the previous case withg= 1) and the additionof an edge. The method proposed here is based on continuous perturbations andthe study of their differential inequalities associated. Within rather economicalinformation (namely, the degrees of the vertices involved in the perturbation), thebest possible inequalities are obtained. In addition, the cases when equalities areattained are characterized. The asymptotic behavior of thebounds obtained isalso discussed. For instance, ifGis a connected graph andGudenotes the graphobtained fromGby adding a pendant edge at vertexuwith degreeδu, then,λ(Gu)≤λ(G) +δuλ3(G)+ o(1λ3(G))