Constructing Fifteen Infinite Classes of Nonregular Bipartite Integral Graphs
نویسندگان
چکیده
منابع مشابه
Constructing Fifteen Infinite Classes of Nonregular Bipartite Integral Graphs
A graph is called integral if all its eigenvalues (of the adjacency matrix) are integers. In this paper, the graphs S1(t) = K1,t, S2(n, t), S3(m,n, t), S4(m,n, p, q), S5(m,n), S6(m,n, t), S8(m,n), S9(m,n, p, q), S10(n), S13(m,n), S17(m,n, p, q), S18(n, p, q, t), S19(m,n, p, t), S20(n, p, q) and S21(m, t) are defined. We construct the fifteen classes of larger graphs from the known 15 smaller in...
متن کاملGraphs Classes Related to Bipartite Graphs
We continue the study of the following general problem on vertex colorings of graphs. Suppose that some vertices of a graph G are assigned to some colors. Can this “precoloring” be extended to a proper coloring of G with at most k colors (for some given k)? Here we investigate the complexity status of precoloring extendibility on some graph classes which are related to bipartite graphs, giving ...
متن کاملInfinite homogeneous bipartite graphs with unequal sides
We call a bipartite graph homogeneous if every finite partial automorphism which respects left and right can be extended to a total automorphism. A (κ, λ) bipartite graph is a bipartite graph with left side of size κ and right side of size λ. We show that there is a homogeneous (א0, 2א0) bipartite graph of girth 4 (thus answering negatively a question by Kupitz and Perles), and that depending o...
متن کاملSome Infinite Classes of Fullerene Graphs
A fullerene graph is a 3 regular planar simple finite graph with pentagon or hexagon faces. In these graphs the number of pentagon faces is 12. Therefore, any fullerene graph can be characterized by number of its hexagon faces. In this note, for any h > 1, we will construct a fullerene graph with h hexagon faces. Then, using the leapfrogging process we will construct stable fullerenes with 20 +...
متن کاملPrecoloring Extension. Ii. Graphs Classes Related to Bipartite Graphs
We continue the study of the following general problem on vertex col-orings of graphs. Suppose that some vertices of a graph G are assigned to some colors. Can this \precoloring" be extended to a proper coloring of G with at most k colors (for some given k)? Here we investigate the complexity status of precoloring extendibility on some graph classes which are related to bipartite graphs, giving...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Electronic Journal of Combinatorics
سال: 2008
ISSN: 1077-8926
DOI: 10.37236/732