Positive Q-matrices of graphs

• Autorzy: Nobuaki Obata
• Języki publikacji: EN

Abstrakty

EN

The Q-matrix of a connected graph 𝒢 = (V,E) is $Q = (q^{∂(x,y)})_{x,y∈ V}$, where ∂(x,y) is the graph distance. Let q(𝒢) be the range of q ∈ (-1,1) for which the Q-matrix is strictly positive. We obtain a sufficient condition for the equality q(𝒢̃) = q(𝒢) where 𝒢̃ is an extension of a finite graph 𝒢 by joining a square. Some concrete examples are discussed.

Kategorie tematyczne

• 05C50: Graphs and linear algebra (matrices, eigenvalues, etc.)
• 43A35: Positive definite functions on groups, semigroups, etc.

• Wydawca: Institute of Mathematics Polish Academy of Sciences
• Czasopismo: Studia Mathematica
• Rocznik: 2007
• Tom: 179
• Numer: 1
• Strony: 81-97

Daty

wydano

2007

Twórcy

autor

Nobuaki Obata

• Graduate School of Information Sciences, Tohoku University, Sendai 980-8579, Japan

Identyfikatory

DOI

10.4064/sm179-1-7