William D. Weakley 1
1Department of Mathematical Sciences Indiana University – Purdue University Fort Wayne, IN 46805
Abstract:

The queen’s graph \(Q_n\) has the squares of the \(n \times n\) chessboard as its vertices; two squares are adjacent if they are in the same row, column, or diagonal. Let \(\gamma(Q_n)\) be the minimum size of a dominating set of \(Q_n\). Spencer proved that \(\gamma(Q_n) \geq {(n-1)}/{2}\) for all \(n\), and the author showed \(\gamma(Q_n) = {(n-1)}/{2}\) implies \(n \equiv 3 \pmod{4}\) and any minimum dominating set of \(Q_n\) is independent.

Define a sequence by \(n_1 = 3\), \(n_2 = 11\), and for \(i > 2\), \(n_i = 4n_{i-1} – n_{i-2} – 2\). We show that if \(\gamma(Q_n) = {(n-1)}/{2}\) then \(n\) is a member of the sequence other than \(n_3 = 39\), and (counting from the center) the rows and columns occupied by any minimum dominating set of \(Q_n\) are exactly the even-numbered ones. This improvement in the lower bound enables us to find the exact value of \(\gamma(Q_n)\) for several \(n\); \(\gamma(Q_n) = {(n+1)}/{2}\) is shown here for \(n = 23, 39\), and elsewhere for \(n = 27, 71, 91, 115, 131\).

Subhamoy Maitra1, Palash Sarkar2
1 Computer and Statistical Service Centre Indian Statistical Institute 203, B.T. Road, Calcutta 700 035, INDIA
2Department of Combinatorics and Optimization University of Waterloo 200 University Avenue West Waterloo, Ontario Canada N2L 3G1
Abstract:

A characterization of symmetric bent functions has been presented in [3]. Here, we provide a simple proof of the same result.

E. J. Cockayne1, O. Favaront2, C. M. Mynhardt3
1Department of Mathematics, University of Victoria, P. O. Box 3045, Victoria, BC, CANADA V8W 3P4;
2LRI, Bat. 490, Université Paris-Sud, 91405 Orsay Cedex, FRANCE;
3Department of Mathematics, University of South Africa, P. O. Box 392, Unisa, 0003 SOUTH AFRICA;
Abstract:

We prove that the total domination number of an \(n\)-vertex claw-free cubic graph is at most \({n}/{2}\).

Martin BACA1, Mirka MILLER2
1 Department of Applied Mathematics Technical University, Ko8ice, Slovak Republic
2Department of Computer Science and Software Engineering The University of Newcastle, Australia
Abstract:

This paper deals with the problem of labeling the edges of a plane graph in such a way that the weight of a face is the sum of the labels of the edges surrounding that face. The paper describes \((a, d)\)-face antimagic labeling of a certain class of convex polytopes.

Abstract:

Below, we prove that there are exactly 244 nonisomorphic cyclic decompositions of the complete graph \(K_{25}\) into cubes. The full list of such decompositions is given in the Appendix.

J. Cormie1, V. Lineki 1, Sheng Jiang2, Rui-Chen Chen2
1 Department of Mathematics and Statistics University of Winnipeg Winnipeg, Manitoba, R3B 2E9 CANADA
2Department of Mathematics Yangzhou University Yangzhou, Jiangsu 225002 P. R. CHINA
Abstract:

The magic square is probably the most popular and well-studied topic in recreational mathematics. We investigate a variation on this classic puzzle — the antimagic square. We review the history of the problem, and the structure of the design. We then present computational results on the enumeration and construction. Finally, we describe a construction for all orders.

Bader F. AlBdaiwi1, Peter Horak1
1 Department of Mathematics and Computer Science Kuwait University Kuwait
Abstract:

We establish a necessary and sufficient condition for the existence of a perfect distance-\(d\) placement in 3-dimensional tori, for both regular and irregular cases.

Sanming Zhou1
1 Department of Mathematics and Statistics The University of Melbourne Parkville, VIC 3010, Australia
Abstract:

Let \(G\) be a simple graph and \(f\) a function from the vertices of \(G\) to the set of positive integers. An \((f, n)\)-coloring of \(G\) is an assignment of \(n\) colors to the vertices of \(G\) such that each vertex \(x\) is adjacent to less than \(f(x)\) vertices with the same color as \(x\). The minimum \(n\) such that an \((f, n)\)-coloring of \(G\) exists is defined to be the \(f\)-chromatic number of \(G\). In this paper, we address a study of this kind of locally restricted coloring.

Peter Adams1, Darryn Bryant1, Heather Gavlas 2
1 Department of Mathematics University of Queensland Qld 4072 Australia
2Department of Mathematics and Statistics Grand Valley State University Allendale, MI 49401 USA
Abstract:

A \(G\)-decomposition of the complete graph \(K_v\) is a set \({S}\) of subgraphs of \(K_v\), each isomorphic to \(G\), such that the edge set of \(K_v\) is partitioned by the edge sets of the subgraphs in \({S}\). For all positive integers \(v\) and every 2-regular graph \(G\) with ten or fewer vertices, we prove necessary and sufficient conditions for the existence of a \(G\)-decomposition of \(K_v\).

A. Averbuch1, Y. Roditty1, B. Shoham1
1Department of Computer Science School of Computer Sciences Tel Aviv University Ramat Aviv, Tel Aviv 69978 Israel
Abstract:

A broadcast graph on \(n\) vertices is a network in which a message can be broadcast in minimum possible (\(=\lceil \log_2 n \rceil\)) time from any vertex. Broadcast graphs which have the smallest number of edges are called \emph{Minimum Broadcast Graphs}, and are subjects of intensive study. In this paper, we study how the number of edges in minimum broadcast graphs decreases, as we allow additional time over \(\lceil \log_2 n \rceil\).

We improve results obtained by Shastri in [15] and prove a conjecture posed by Shastri in [15, 16].

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