Oriented bipartite graphs and the Goldbach graph
نویسندگان
چکیده
In this paper, we study oriented bipartite graphs. particular, introduce “bitransitive” Several characterizations of bitransitive bitournaments are obtained. We show that bitounaments equivalent to acyclic bitournaments. As applications, characterize with Hamiltonian paths, determine the number non-isomorphic a given order, and solve graph-isomorphism problem in linear time for Next, prove well-known Caccetta-Häggkvist Conjecture graphs some cases which it is unsolved, general, also concept undirected as well “odd-even” terms them. fact, any graph (acyclic graph) can be represented by odd-even (oriented graph). obtain conditions connectedness This their motivated special family call “Goldbach graphs”. famous Goldbach's conjecture Goldbach other theoretic conjectures (e.g., twin prime conjecture) related various parameters graphs, motivating us nature vertex-degrees independent sets these Finally, observe properties small vertices.
منابع مشابه
Oriented Bipartite Graphs and the Goldbach Graph
In this paper we study oriented bipartite graphs. In particular, several characterizations of bitournaments are obtained. We introduce the concept of odd-even graphs and show that any (oriented) bipartite graph can be represented by some (oriented) odd-even graph. We show that the famous Goldbach’s conjecture is equivalent to the connectedness of certain odd-even graphs.
متن کاملThe p-median and p-center Problems on Bipartite Graphs
Let $G$ be a bipartite graph. In this paper we consider the two kind of location problems namely $p$-center and $p$-median problems on bipartite graphs. The $p$-center and $p$-median problems asks to find a subset of vertices of cardinality $p$, so that respectively the maximum and sum of the distances from this set to all other vertices in $G$ is minimized. For each case we present some proper...
متن کاملSkew Spectra of Oriented Bipartite Graphs
A graph G is said to have a parity-linked orientation φ if every even cycle C2k in G is evenly (resp. oddly) oriented whenever k is even (resp. odd). In this paper, this concept is used to provide an affirmative answer to the following conjecture of D. Cui and Y. Hou [D. Cui, Y. Hou, On the skew spectra of Cartesian products of graphs, The Electronic J. Combin. 20(2):#P19, 2013]: Let G = G(X,Y ...
متن کاملScore Sets in Oriented Bipartite Graphs
The set A of distinct scores of the vertices of an oriented bipartite graph D(U, V) is called its score set. We consider the following question: given a finite, nonempty set A of positive integers, is there an oriented bipartite graph D(U, V) such that score set of D(U, V) is A? We conjecture that there is an affirmative answer, and verify this conjecture when | A | = 1, 2, 3, or when A is a ge...
متن کاملMETA-HEURISTIC ALGORITHMS FOR MINIMIZING THE NUMBER OF CROSSING OF COMPLETE GRAPHS AND COMPLETE BIPARTITE GRAPHS
The minimum crossing number problem is among the oldest and most fundamental problems arising in the area of automatic graph drawing. In this paper, eight population-based meta-heuristic algorithms are utilized to tackle the minimum crossing number problem for two special types of graphs, namely complete graphs and complete bipartite graphs. A 2-page book drawing representation is employed for ...
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: Discrete Mathematics
سال: 2021
ISSN: ['1872-681X', '0012-365X']
DOI: https://doi.org/10.1016/j.disc.2021.112497