scholarly journals On Study of Vertex Labeling of Graph Operations

2011 ◽  
Vol 3 (2) ◽  
pp. 291-301
Author(s):  
M. A. Rajan ◽  
N. M. Kembhavimath ◽  
V. Lokesha

Vertices of the graphs are labeled from the set of natural numbers from 1 to the order of the given graph. Vertex adjacency label set (AVLS) is the set of ordered pair of vertices and its corresponding label of the graph. A notion of vertex adjacency label number (VALN) is introduced in this paper. For each VLS, VLN of graph is the sum of labels of all the adjacent pairs of the vertices of the graph. is the maximum number among all the VALNs of the  different labeling of the graph and the corresponding VALS is defined as maximal vertex  adjacency label set . In this paper  for different graph operations are discussed. Keywords: Subdivision; Graph labeling; Direct sum; Direct product.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i26222                  J. Sci. Res. 3 (2), 291-301 (2011) 

2001 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
P. Schultz

G is reduced torsion-free A belian group such that for every direct sum ⊕G of copies of G, Ext(⊕G, ⊕G) = 0 if and only if G is a free module over a rank 1 ring. For every direct product ΠG of copies of G, Ext(ΠG,ΠG) = 0 if and only if G is cotorsion.This paper began as a Research Report of the Department of Mathematics of the University of Western Australia in 1988, and circulated among members of the Abelian group community. However, it was never submitted for publication. The results have been cited, widely, and since copies of the original research report are no longer available, the paper is presented here in its original form in Sections 1 to 5. In Section 6, I survey the progress that has been made in the topic since 1988.


1961 ◽  
Vol 13 ◽  
pp. 192-200 ◽  
Author(s):  
Christine W. Ayoub

In this paper we consider again the group-theoretic configuration studied in (1) and (2). Let G be an additive group (not necessarily abelian), let M be a system of operators for G, and let ϕ be a family of admissible subgroups which form a complete lattice relative to intersection and compositum. Under these circumstances we call G an M — ϕ group. In (1) we studied the normal chains for an M — ϕ group and the relation between certain normal chains. In (2) we considered the possibility of representing an M — ϕ group as the direct sum of certain of its subgroups, and proved that with suitable restrictions on the M — ϕ group the analogue of the following theorem for finite groups holds: A group is the direct product of its Sylow subgroups if and only if it is nilpotent. Here we show that under suitable hypotheses (hypotheses (I), (II), and (III) stated at the beginning of §3) it is possible to generalize to M — ϕ groups many of the Sylow theorems of classical group theorem.


2019 ◽  
Vol 19 (02) ◽  
pp. 1950001
Author(s):  
YINGYING ZHANG ◽  
XIAOYU ZHU

A path in a vertex-colored graph is a vertex-proper path if any two internal adjacent vertices differ in color. A vertex-colored graph is proper vertex k-connected if any two vertices of the graph are connected by k disjoint vertex-proper paths of the graph. For a k-connected graph G, the proper vertex k-connection number of G, denoted by pvck(G), is defined as the smallest number of colors required to make G proper vertex k-connected. A vertex-colored graph is strong proper vertex-connected, if for any two vertices u, v of the graph, there exists a vertex-proper u-v geodesic. For a connected graph G, the strong proper vertex-connection number of G, denoted by spvc(G), is the smallest number of colors required to make G strong proper vertex-connected. In this paper, we study the proper vertex k-connection number and the strong proper vertex-connection number on the join of two graphs, the Cartesian, lexicographic, strong and direct product, and present exact values or upper bounds for these operations of graphs. Then we apply these results to some instances of Cartesian and lexicographic product networks.


1991 ◽  
Vol 1 (1) ◽  
pp. 121-124
Author(s):  
Richard S. Bird

The problem of computing the smallest natural number not contained in a given set of natural numbers has a number of practical applications. Typically, the given set represents the indices of a class of objects ‘in use’ and it is required to find a ‘free’ object with smallest index. Our purpose in this article is to derive a linear-time functional program for the problem. There is an easy solution if arrays capable of being accessed and updated in constant time are available, but we aim for an algorithm that employs only standard lists. Noteworthy is the fact that, although an algorithm using lists is the result, the derivation is carried out almost entirely in the world of sets.


2017 ◽  
Vol 16 (12) ◽  
pp. 1750239 ◽  
Author(s):  
Irene Paniello

We study the structure of genetic coalgebras and prove the existence of a decomposition as the direct sum of indecomposable subcoalgebras with genetic realization. To obtain such a decomposition, we first define a new multiplication for their related cubic stochastic matrices of type (1,2) and then, considering these matrices as cubic non-negative, we show how this new multiplication induces an index classification which can be used to study the genetic coalgebra structure. Genetically, the given coalgebra decomposition can be understood as a genetic clustering of the different types for the genetic trait defining the genetic coalgebra, which allows us to identify isolated ancestral populations.


Author(s):  
José Ramón Játem Lásser

  In this article we have presented a new approach to define algebras using for a natural number k ≥ 2, the set of natural numbers in base k, none of their digits equal to zero. The study was developed in the context of vector R -spaces and the vector space definitions of the formal multiples of any element x of the field R, of the direct sum of vector spaces and binary operations on vector spaces were used. The results obtained were the construction of a vector space denoted by V, on the basis of the particular set of natural numbers in base k mentioned, which allowed novel ways of defining the well-known and very important algebras of complex numbers and that of quaternions on R as quotients of ideals of V, for suitably chosen ideals I. With this new approach and with the help of the vector spaces V, known algebras can be presented in a different way than those found up to now, by using certain ideals of those spaces in their quotient form. The spaces V can be over any field K and other algebras such as Clifford algebras can be constructed using this procedure.   Keywords: Algebras, Quotients in algebras, Complex numbers and quaternions as quotients of algebras.   Abstract En este artículo se ha presentado un nuevo enfoque para definir álgebras usando para un número natural k ≥ 2, el conjunto de números naturales en base k, ninguno de sus dígitos iguales a cero. El estudio se desarrolló en el contexto de los R-espacios vectoriales y se usaron las definiciones de espacio vectorial de los múltiplos formales de un elemento cualquiera x del cuerpo R, de la suma directa de espacios vectoriales y operaciones binarias sobre espacios vectoriales. Los resultados obtenidos fueron la construcción de un espacio vectorial denotado por V, sobre la base del particular conjunto de números naturales en base k mencionado, que permitió novedosas formas de definir las conocidas y muy importantes álgebras de los números complejos y la de los cuaterniones sobre R como cocientes de ideales de V, para ideales I convenientemente elegidos. Con este nuevo enfoque y con la ayuda de los espacios vectoriales V se pueden presentar álgebras conocidas de manera distinta a las encontradas hasta ahora, al usar en su forma de cociente ciertos ideales de esos espacios V. Los espacios V pueden ser sobre cualquier cuerpo K y otras álgebras como las álgebras de Clifford se pueden construir usando este procedimiento.   Palabras claves: Algebras, cocientes en álgebras, Números complejos y quaterniones como cocientes en álgebras.  


1973 ◽  
Vol 25 (5) ◽  
pp. 1002-1005
Author(s):  
Thomas Cheatham

In [4, Theorem 4.1, p. 45], Enochs characterizes the integral domains with the property that the direct product of any family of torsion-free covers is a torsion-free cover. In a setting which includes integral domains as a special case, we consider the corresponding question for direct sums. We use the notion of torsion introduced by Goldie [5]. Among commutative rings, we show that the property “any direct sum of torsion-free covers is a torsion-free cover“ characterizes the semi-simple Artinian rings.


Author(s):  
GASPAR MAYOR ◽  
JAUME MONREAL

This paper deals with triangular norms and conorms defined on the extended set N of natural numbers ordered by divisibility. From the fundamental theorem of arithmetic, N can be identified with a lattice of functions from the set of primes to the complete chain {0, 1, 2, …, +∞}, thus our knowledge about (divisible) t-norms on this chain can be applied to the study of t-norms on N. A characterization of those t-norms on N which are a direct product of t-norms on {0, 1, 2, …, +∞} is given and, after introducing the concept of T-prime (prime with respect to a t-norm T), a theorem about the existence of a T-prime decomposition is obtained. This result generalizes the fundamental theorem of arithmetic.


1954 ◽  
Vol 19 (3) ◽  
pp. 197-200 ◽  
Author(s):  
Václav Edvard Beneš

1. In this paper we construct a model for part of the system NF of [4]. Specifically, we define a relation R of natural numbers such that the R-relativiseds of all the axioms except P9 of Hailperin's finitization [2] of NF become theorems of say Zermelo set theory. We start with an informal explanation of the model.2. Scrutiny of P1-P8 of [2] suggests that a model for these axioms might be constructed by so to speak starting with a universe that contained a “universe set” and a “cardinal 1”, and passing to its closure under the operations implicit in P1-P7, viz., the Boolean, the domain, the direct product, the converse, and the mixtures of product and inverse operations represented by P3 and P4. To obtain such closure we must find a way of representing the operations that involve ordered pairs and triples.We take as universe of the model the set of natural numbers ω; we let 0 represent the “universe set” and 1 represent “cardinal 1”. Then, in order to be able to refer in the model to the unordered pair of two sets, we determine all representatives of unordered pairs in advance by assigning them the even numbers in unique fashion (see d3 and d25); we can now define the operations that involve ordered pairs and triples, and obtain closure under them using the odd numbers. It remains to weed out, as in d26, the unnecessary sets so as to satisfy the axiom of extensionality.


1950 ◽  
Vol 2 ◽  
pp. 152-165 ◽  
Author(s):  
Heinrich Behnke ◽  
Karl Stein

In the present paper, the authors extend the Cousin theorems and the continuity theorem, using some previous results on analytic functions connected with open Riemann surfaces.The Cousin theorems, concerning the existence of analytic functions of several complex variables with prescribed poles and zeros in a given domain, have been generalized in various manners, but only in the case where the domain is schlicht. The authors proceed to the case where the given domain is the direct product of n open Riemann surfaces. They prove the following two theorems.


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