All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 49 Next

Displaying 961 – 980 of 1336

Showing per page

On the inverse of the adjacency matrix of a graph

Alexander Farrugia, John Baptist Gauci, Irene Sciriha (2013)

Special Matrices

A real symmetric matrix G with zero diagonal encodes the adjacencies of the vertices of a graph G with weighted edges and no loops. A graph associated with a n × n non–singular matrix with zero entries on the diagonal such that all its (n − 1) × (n − 1) principal submatrices are singular is said to be a NSSD. We show that the class of NSSDs is closed under taking the inverse of G. We present results on the nullities of one– and two–vertex deleted subgraphs of a NSSD. It is shown that a necessary...

On the isoperimetry of graphs with many ends

Christophe Pittet (1998)

Colloquium Mathematicae

Let X be a connected graph with uniformly bounded degree. We show that if there is a radius r such that, by removing from X any ball of radius r, we get at least three unbounded connected components, then X satisfies a strong isoperimetric inequality. In particular, the non-reduced l 2 -cohomology of X coincides with the reduced l 2 -cohomology of X and is of uncountable dimension. (Those facts are well known when X is the Cayley graph of a finitely generated group with infinitely many ends.)

On the k-gamma q-distribution

Rafael Díaz, Camilo Ortiz, Eddy Pariguan (2010)

Open Mathematics

We provide combinatorial as well as probabilistic interpretations for the q-analogue of the Pochhammer k-symbol introduced by Díaz and Teruel. We introduce q-analogues of the Mellin transform in order to study the q-analogue of the k-gamma distribution.

On the Laplacian energy of a graph

Mirjana Lazić (2006)

Czechoslovak Mathematical Journal

In this paper we consider the energy of a simple graph with respect to its Laplacian eigenvalues, and prove some basic properties of this energy. In particular, we find the minimal value of this energy in the class of all connected graphs on n vertices ( n = 1 , 2 , ... ) . Besides, we consider the class of all connected graphs whose Laplacian energy is uniformly bounded by a constant α ≥ 4 , and completely describe this class in the case α = 40 .

On the Laplacian, signless Laplacian and normalized Laplacian characteristic polynomials of a graph

Ji-Ming Guo, Jianxi Li, Wai Chee Shiu (2013)

Czechoslovak Mathematical Journal

The Laplacian, signless Laplacian and normalized Laplacian characteristic polynomials of a graph are the characteristic polynomials of its Laplacian matrix, signless Laplacian matrix and normalized Laplacian matrix, respectively. In this paper, we mainly derive six reduction procedures on the Laplacian, signless Laplacian and normalized Laplacian characteristic polynomials of a graph which can be used to construct larger Laplacian, signless Laplacian and normalized Laplacian cospectral graphs, respectively....

On the lattice of additive hereditary properties of finite graphs

Ján Jakubík (2002)

Discussiones Mathematicae - General Algebra and Applications

In this paper it is proved that the lattice of additive hereditary properties of finite graphs is completely distributive and that it does not satisfy the Jordan-Dedekind condition for infinite chains.

Currently displaying 961 – 980 of 1336