搜索结果: 1-13 共查到“代数学其他学科 Graphs”相关记录13条 . 查询时间(0.015 秒)
The incidence Hopf algebra of graphs
combinatorial Hopf algebra graph chromatic polynomial
2011/2/24
The graph algebra is a commutative, cocommutative, graded,connected incidence Hopf algebra, whose basis elements correspond to fi-nite simple graphs and whose Hopf product and coproduct admit simple c...
Complete solution to a conjecture on the maximal energy of unicyclic graphs
Complete solution conjecture unicyclic graphs
2010/11/24
For a given simple graph $G$, the energy of $G$ denoted by $E(G)$, is defined as the sum of the absolute values of all eigenvalues of its adjacency matrix. Let $P_n^{\ell}$ be the unicyclic graph obt...
In this paper we consider a model for the spread of a stochastic SIR (Susceptible $\to$ Infectious $\to$ Removed) epidemic on a network of individuals described by a random intersection graph. The nu...
Moving closer: contractive maps on discrete metric spaces and graphs
Moving closer discrete metric spaces and graphs
2010/11/23
We consider discrete metric spaces and we look for non-constant contractions. We introduce the notion of contractive map and we characterize the spaces with non-constant contractive maps. We provide s...
On upper-critical graphs
On upper-critical graphs math
2010/11/23
This work introduces the concept of upper-critical graphs, in a complementary way of the conventional (lower)critical graphs: an element $x$ of a graph $G$ is called critical if $\chi(G-x)<\chi(G)$. ...
String diagrams are a powerful tool for reasoning about physical processes, logic circuits, tensor networks, and many other compositional structures. The distinguishing feature of these diagrams is t...
Cyclotomic Matrices and Graphs over the ring of integers of some imaginary quadratic fields
Cyclotomic Matrices Graphs imaginary quadratic fields
2010/11/18
We determine all Hermitian $\mathcal{O}_{\Q(\sqrt{d})}$-matrices for which every eigenvalue is in the interval [-2,2], for each d in {-2,-7,-11,-15\}. To do so, we generalise charged signed graphs to...
We present a generalization of the construction of graphs by Lubotzky, Phillips and Sarnak in their celebrated article "Ramanujan graphs". The new approach consists in using octonion algebras rather ...
The competition numbers of Hamming graphs with diameter at most three
Hamming graphs diameter
2010/11/18
The competition graph of a digraph D is a graph which has the same vertex set as D and has an edge between x and y if and only if there exists a vertex v in D such that (x,v) and (y,v) are arcs of D. ...
Vertex subsets with minimal width and dual width in $Q$-polynomial distance-regular graphs
Vertex subsets $Q$-polynomial distance-regular graphs
2010/11/15
We study $Q$-polynomial distance-regular graphs from the point of view of what we call descendents, that is to say, those vertex subsets with the property that the width $w$ and dual width $w^*$ sati...
We define two coproducts for cycle-free oriented graphs, thus building up two commutative con- nected graded Hopf algebras, such that one is a comodule-coalgebra on the other, thus generalizing the re...
Star graphs: threaded distance trees and E-sets
Star graphs threaded distance trees E-sets
2010/11/22
The distribution of distances in the star graph $ST_n$, ($1
We define a number of natural (from geometric and combinatorial points of view) deformation spaces of valuations on finite graphs, and study functions over these deformation spaces. These functions in...