Alexander Clifton1, Abdollah Khodkar2
1Department of Mathematics Massachusetts Institute of Technology Cambridge, MA 02139
2University of West Georgia Department of Mathematics University of West Georgia Carrollton, GA 30118
Abstract:

A graph \(G\) with vertex set \(V\) and edge set \(E\) is called super edge-graceful if there is a bijection \(f\) from \(E\) to \(\{0, \pm 1, \pm 2, \dots, \pm (|E| – 1)/2\}\) when \(|E|\) is odd and from \(E\) to \(\{\pm1, \pm2, \dots, \pm|E|/2\}\) when \(|E|\) is even, such that the induced vertex labeling \(f^*\) defined by \(f^*(u) = \sum f(uv)\) over all edges \(uv\) is a bijection from \(V\) to \(\{0, \pm 1, \pm 2, \dots, \pm (|V| – 1)/2\}\) when \(|V|\) is odd and from \(V\) to \(\{\pm1, \pm2, \dots, \pm|V|/2\}\) when \(|V|\) is even. A kite is a graph formed by merging a cycle and a path at an endpoint of the path. In this paper, we prove that all kites with \(n \geq 5\) vertices, \(n \neq 6\), are super edge-graceful.

Abdollah Khodkar1, Oliver Sawin2, Lisa Mueller3, WonHyuk Choi4
1Department of Mathematics University of West Georgia Carrollton, GA 30082
2Department of Mathematics, Rensselaer Polytechnic Institute Troy, NY 12180
3Department of Mathematics, California State University, Fullerton Fullerton, CA 92833
4Department of Mathematics, Pomona College Claremont, CA 91711
Abstract:

A graph with \(v\) vertices is \((r)\)-pancyclic if it contains precisely \(r\) cycles of every length from \(3\) to \(v\). A bipartite graph with an even number of vertices \(v\) is said to be \((r)\)-bipancyclic if it contains precisely \(r\) cycles of each even length from \(4\) to \(v\). A bipartite graph with an odd number of vertices \(v\) and minimum degree at least \(2\) is said to be oddly \((r)\)-bipancyclic if it contains precisely \(r\) cycles of each even length from \(4\) to \(v-1\). In this paper, using a computer search, we classify all \((r)\)-pancyclic and \((r)\)-bipancyclic graphs, \(r \geq 2\), with \(v\) vertices and at most \(v+5\) edges. We also classify all oddly \((r)\)-bipancyclic graphs, \(r \geq 1\), with \(v\) vertices and at most \(v+4\) edges.

Dalibor Froncek1
1Department of Mathematics and Statistics University of Minnesota Duluth 1117 University Drive Duluth, MN 55812-3000, U.S.A.
Abstract:

A handicap distance antimagic labeling of a graph \(G = (V,E)\) with \(n\) vertices is a bijection \(f : V \to \{1,2,\dots,n\}\) with the property that \(f(x_i) = i\) and the sequence of the weights \(w(x_1), w(x_2), \dots, w(x_n)\) (where \(w(x_i) = \sum_{x_j \in N(x_i)}{f(x_j)}\)) forms an increasing arithmetic progression. A graph \(G\) is a handicap distance antimagic graph if it allows a handicap distance antimagic labeling.

We construct regular handicap distance antimagic graphs for every feasible odd order.

Lilian Markenzon1, Christina F. E. M. Waga2
1NCE – Universidade Federal do Rio de Janeiro
2IME – Universidade do Estado do Rio de Janeiro
Abstract:

A well-known subclass of chordal graphs is formed by proper interval graphs. Due to their very special structural properties, several problems proved hard to solve for interval graphs can have better solutions for this subclass. In this paper, we address the recognition problem, proposing an update of one of the first existing linear algorithms. The outcome is a simple and efficient algorithm. In addition, we present a certifying algorithm for the recognition of proper interval graphs

W. D. Wallis1
1Department of Mathematics, Southern Illinois University, Carbondale, IL 62901, USA
Abstract:

A bipartite graph on \(2n\) vertices is called bipancyclic if it contains cycles of every length from \(4\) to \(2n\). In this paper we address the question: what is the minimum number of edges in a bipancyclic graph? We present a simple analysis of some small orders using chord patterns.

Gary Chartrand1, Teresa W. Haynes2, Stephen T. Hedetniemi3, Ping Zhang4
1Department of Mathematics Western Michigan University Kalamazoo, MI 49008-5248, USA
2Department of Mathematics and Statistics East Tennessee State University Johnson City, TN 37614-0002 USA
3Department of Mathematics University of Johannesburg Auckland Park, 2006 South Africa
4 Department of Mathematics Western Michigan University Kalamazoo, MI 49008-5248, USA
Abstract:

A vertex set \(U \subset V\) in a connected graph \(G = (V, E)\) is a cutset if \(G – U\) is disconnected. If no proper subset of \(U\) is also a cutset of \(G\), then \(U\) is a minimal cutset. An \(\mathcal{MVC}\)-partition \(\pi = \{V_1, V_2, \dots, V_k\}\) of the vertex set \(V(G)\) of a connected graph \(G\) is a partition of \(V(G)\).

Futaba Fujie1, Zhenming Bi2, Ping Zhang2
1Graduate School of Mathematics, Nagoya University, Nagoya, 464-8602, Japan.
2Department of Mathematics, Western Michigan University, Kalamazoo, MI 49008, USA.
Abstract:

A Hamiltonian graph \(G\) is said to be \(\ell\)-path-Hamiltonian, where \(\ell\) is a positive integer less than or equal to the order of \(G\), if every path of order \(\ell\) in \(G\) is a subpath of some Hamiltonian cycle in \(G\). The Hamiltonian cycle extension number of \(G\) is the maximum positive integer \(L\) for which \(G\) is \(\ell\)-path-Hamiltonian for every integer \(\ell\) with \(1 \leq \ell \leq L\). Hamiltonian cycle extension numbers are determined for several well-known cubic Hamiltonian graphs. It is shown that if \(G\) is a cubic Hamiltonian graph with girth \(g\), where \(3 \leq g \leq 7\), then \(G\) is \(\ell\)-path-Hamiltonian only if \(1 \leq \ell \leq g\).

Drake Olejniczak1, Ping Zhang1
1Department of Mathematics Western Michigan University Kalamazoo, MI 49008-5248, USA
Abstract:

In a red-blue coloring of a graph \(G\), every edge of \(G\) is colored red or blue. For two graphs \(F\) and \(H\), the Ramsey number \(R(F, H)\) of \(F\) and \(H\) is the smallest positive integer \(n\) such that every red-blue coloring of the complete graph \(K_n\) of order \(n\) results in either a subgraph isomorphic to \(F\) all of whose edges are colored red or a subgraph isomorphic to \(H\) all of whose edges are colored blue. While the study of Ramsey numbers has been a popular area of research in graph theory, over the years a number of variations of Ramsey numbers have been introduced. We look at several of these, with special emphasis on some of those introduced more recently.

Zhenming Bi1, Alexis Byers1, Ping Zhang1
1Department of Mathematics Western Michigan University Kalamazoo, MI 49008-5248, USA
Abstract:

For a graph \(G\) of size \(m\), a graceful labeling of \(G\) is an injective function \(f : V(G) \to \{0, 1, \dots, m\}\) that gives rise to a bijective function \(f’ : E(G) \to \{1, 2, \dots, m\}\) defined by \(f'(uv) = |f(u) – f(v)|\). A graph \(G\) is graceful if \(G\) has a graceful labeling. Over the years, a number of variations of graceful labelings have been introduced, some of which have been described in terms of colorings. We look at several of these, with special emphasis on some of those introduced more recently.

Zhenming Bi1, Sean English1, Ian Hart1, Ping Zhang1
1 Department of Mathematics Western Michigan University Kalamazoo, MI 49008-5248, USA
Abstract:

For a connected graph \(G\) of order at least \(3\), let \(c : E(G) \to \{1, 2, \dots, k\}\) be an edge coloring of \(G\) where adjacent edges may be colored the same. Then \(c\) induces a vertex coloring \(c’\) of \(G\) by assigning to each vertex \(v\) of \(G\) the set of colors of the edges incident with \(v\). The edge coloring \(c\) is called a majestic \(k\)-edge coloring of \(G\) if the induced vertex coloring \(c’\) is a proper vertex coloring of \(G\). The minimum positive integer \(k\) for which a graph \(G\) has a majestic \(k\)-edge coloring is the majestic chromatic index of \(G\) and denoted by \(\chi_{m}^{‘} (G)\). For a graph \(G\) with \(\chi_{m}^{‘}(G) = k\), the minimum number of distinct vertex colors induced by a majestic \(k\)-edge coloring is called the majestic chromatic number of \(G\) and denoted by \(\psi(G)\). Thus, \(\psi(G)\) is at least as large as the chromatic number \(\chi(G)\) of a graph \(G\). Majestic chromatic indexes and numbers are determined for several well-known classes of graphs. Furthermore, relationships among the three chromatic parameters \(\chi_m(G)\), \(\psi(G)\), and \(\chi(G)\) of a graph \(G\) are investigated.

E-mail Alert

Add your e-mail address to receive upcoming issues of Journal of Combinatorial Mathematics and Combinatorial Computing (JCMCC).

Special Issues

The Combinatorial Press Editorial Office routinely extends invitations to scholars for the guest editing of Special Issues, focusing on topics of interest to the scientific community. We actively encourage proposals from our readers and authors, directly submitted to us, encompassing subjects within their respective fields of expertise. The Editorial Team, in conjunction with the Editor-in-Chief, will supervise the appointment of Guest Editors and scrutinize Special Issue proposals to ensure content relevance and appropriateness for the journal. To propose a Special Issue, kindly complete all required information for submission;