Ali Ahmad1
1College of Computer Science & Information Technology, Jazan University, Jazan, Saudi Arabia.
Abstract:

Let us consider a~simple connected undirected graph \(G=(V,E)\). For a~graph \(G\) we define a~\(k\)-labeling \(\phi: V(G)\to \{1,2, \dots, k\}\) to be a~distance irregular vertex \(k\)-labeling of the graph \(G\) if for every two different vertices \(u\) and \(v\) of \(G\), one has \(wt(u) \ne wt(v),\) where the weight of a~vertex \(u\) in the labeling \(\phi\) is \(wt(u)=\sum\limits_{v\in N(u)}\phi(v),\) where \(N(u)\) is the set of neighbors of \(u\). The minimum \(k\) for which the graph \(G\) has a~distance irregular vertex \(k\)-labeling is known as distance irregularity strength of \(G,\) it is denoted as \(dis(G)\). In this paper, we determine the exact value of the distance irregularity strength of corona product of cycle and path with complete graph of order \(1,\) friendship graph, Jahangir graph and helm graph. For future research, we suggest some open problems for researchers of the same domain of study.

Muhammad Junaid Ali Junjua1, Khurram Shabbir1, Asim Naseem1
1Govt. College University, Lahore, Pakistan.
Abstract:

Elimination ideals are monomial ideals associated to simple graphs, not necessarily square–free, was introduced by Anwar and Khalid. These ideals are Borel type. In this paper, we obtain sharp combinatorial upper bounds of the Castelnuovo–Mumford regularity of elimination ideals corresponding to certain family of graphs.

Asim Naseem1, Khurram Shabbir1, M. Ramzan1
1Govt. College University, Lahore, Pakistan.
Abstract:

Let \(G\) be a simple connected graph with vertex set \(V\) and diameter \(d\). An injective function \(c: V\rightarrow \{1,2,3,\ldots\}\) is called a radio labeling of \(G\) if \({|c(x) c(y)|+d(x,y)\geq d+1}\) for all distinct \(x,y\in V\), where \(d(x,y)\) is the distance between vertices \(x\) and \(y\). The largest number in the range of \(c\) is called the span of the labeling \(c\). The radio number of \(G\) is the minimum span taken over all radio labelings of \(G\). For a fixed vertex \(z\) of \(G\), the sequence \((l_1,l_2,\ldots,l_r)\) is called the level tuple of \(G\), where \(l_i\) is the number of vertices whose distance from \(z\) is \(i\). Let\(J^k(l_1,l_2,\ldots,l_r)\) be the wedge sum (i.e. one vertex union) of \(k\geq2\) graphs having same level tuple \((l_1,l_2,\ldots,l_r)\). Let \(J(\frac{l_1}{l’_1},\frac{l_2}{l’_2},\ldots,\frac{l_r} {l’_r})\) be the wedge sum of two graphs of same order, having level tuples  \((l_1,l_2,\ldots,l_r)\) and \((l’_1,l’_2,\ldots,l’_r)\). In this paper, we compute the radio number for some sub-families of \(J^k(l_1,l_2,\ldots,l_r)\) and \(J(\frac{l_1}{l’_1},\frac{l_2}{l’_2},\ldots,\frac{l_r}{l’_r})\).

S. Gomathi1, P. Venugopal1, T. Arputha Jose1
1Department of Mathematics, SSN College of Engineering, Kalavakkam, India.
Abstract:

An antipodal labeling is a function \(f\ \)from the vertices of \(G\) to the set of natural numbers such that it satisfies the condition \(d(u,v) + \left| f(u) – f(v) \right| \geq d\), where d is the diameter of \(G\ \)and \(d(u,v)\) is the shortest distance between every pair of distinct vertices  \(u\) and \(v\) of \(G.\) The span of an antipodal labeling \(f\ \)is \(sp(f) = \max\{|f(u) – \ f\ (v)|:u,\ v\, \in \, V(G)\}.\) The antipodal number of~G, denoted by~an(G), is the minimum span of all antipodal labeling of~G. In this paper, we determine the antipodal number of Mongolian tent and Torus grid.

Sin-Min Lee1, Hsin-Hao Su2, Yung-Chin Wang3
1Dept. of Computer Science, 208 MacQuarrie Hall San Jose State Univ., San Jose, CA 95192, USA
2Dept. of Mathematics, Stonehill College 320 Washington St, Easton, MA 02357, USA
3Dept. of Digital Media Design, Tzu-Hui Inst. of Tech. No.367, Sanmin Rd. Nanjhou Hsian, Pingtung, 926, Taiwan
Abstract:

Let \( G \) be a \((p,q)\)-graph in which the edges are labeled \( k, k+1, \ldots, k+q-1 \), where \( k \geq 0 \). The vertex sum for a vertex \( v \) is the sum of the labels of the incident edges at \( v \). If the vertex sums are constant, modulo \( p \), then \( G \) is said to be \( k \)-edge-magic. In this paper, we investigate some classes of cubic graphs which are \( k \)-edge-magic. We also provide a counterexample to a conjecture that any cubic graph of order \( p \equiv 2 \pmod{4} \) is \( k \)-edge-magic for all \( k \).

Iliya Bluskov1
1Department of Mathematics and Statistics Simon Fraser University Burnaby, B.C. CANADA, V5A 186
Abstract:

In this paper, we prove the existence of \(22\) new \(3\)-designs on \(26\) and \(28\) points. The base of the constructions are two designs with a small maximum size of the intersection of any two blocks.

Chang Yanxun1, Ge Gennian2
1Department of Mathematics Northern Jiaotong University Beijing, 100044 P.R. China
2Department of Mathematics Suzhou University Suzhou, 215006 P.R. China
Abstract:

A large set of KTS(\(v\)), denoted by LKTS(\(v\)), is a collection of (\(v-2\)) pairwise disjoint KTS(\(v\)) on the same set. In this article, some new LKTS(\(v\)) is constructed.

M. Mahdian1, E.S. Mahmoodian1
1Department of Computer Engineering Department of Mathematical Science Sharif University of Technology Tehran, Iran
Abstract:

Let \(G\) be a graph with \(v\) vertices. If there exists a list of colors \(S_1, S_2, \ldots, S_v\) on its vertices, each of size \(k\), such that there exists a unique proper coloring for \(G\) from this list of colors, then \(G\) is called a uniquely \(k\)-list colorable graph. We prove that a connected graph is uniquely \(2\)-list colorable if and only if at least one of its blocks is not a cycle, a complete graph, or a complete bipartite graph. For each \(k\), a uniquely \(k\)-list colorable graph is introduced.

T. Gangopadhyay1
1XLRI Jamshedpur Post Box 222 Jamshedpur 831 001 India
Abstract:

A supergraph \(H\) of a graph \(G\) is called tree-covered if \(H – E(G)\) consists of exactly \(|V(G)|\) vertex-disjoint trees, with each tree having exactly one point in common with \(G\). In this paper, we show that if a graph \(G\) can be packed in its complement and if \(H\) is a tree-covered supergraph of \(G\), then \(G\) itself is self-packing unless \(H\) happens to be a member of a specified class of graphs. This is a generalization of earlier results that almost all trees and unicyclic graphs can be packed in their complements.

Bu Yue Hua1, Zhang Ke Min2
1Department of Mathematics Zhejiang Normal University Jinhua 321004 China
2Department of Mathematics Nanjing University Nanjing 210008 China
Abstract:

Let \(T = (V,A)\) be an oriented graph with \(n\) vertices. \(T\) is completely strong path-connected if for each arc \((a,b) \in A\) and \(k\) (\(k = 2, \ldots, n-1\)), there is a path from \(b\) to \(a\) of length \(k\) (denoted by \(P_k(a,b)\)) and a path from \(a\) to \(b\) of length \(k\) (denoted by \(P’_k(a,b)\)) in \(T\). In this paper, we prove that a connected local tournament \(T\) is completely strong path-connected if and only if for each arc \((a,b) \in A\), there exist \(P_2(a,b)\) and \(P’ _2(a,b)\) in \(T\), and \(T\) is not of \(T_1 \ncong T_0\)-\(D’_8\)-type digraph and \(D_8\).

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