A vertex-magic total labeling on a graph G is a one-to-one map λ from V (G) ∪E(G) onto the integers 1, 2, · · · , |V (G) ∪E(G)| with the property that, given any vertex x, λ(x) + ∑ y∼x λ(y) = k for some constant k. In this paper we completely determine which complete bipartite graphs have vertex-magic total labelings.

An edge magic labeling f of a graph with p vertices and q edges is a bijection f: V ∪ E → {1, 2, ..., p + q } such that there exists a constant s for any (x, y) in E satisfying f(x) + f(x, v) + f(y)= s. In this paper, the edge-magic labelings of ncm and some other graphs are discussed.

Let F ={H1, . . . ,Hk} be a family of graphs. A graph G is called totally F -decomposable iffor every linear combination of the form α1e(H1) + · · · + αke(Hk) = e(G) where each αi is anonnegative integer, there is a coloring of the edges of G with α1 + · · · + αk colors such thatexactly αi color classes induce each a copy of Hi, for i = 1, . . . , k. We prove that if F i...

For a tree T , the graph X is T -decomposable if there exists a partition of the edge set of X into isomorphic copies of T . In 1963, Ringel conjectured that K2m+1 can be decomposed by any tree with m edges. Graham and Häggkvist conjectured more generally that every 2m-regular graph can be decomposed by any tree with m edges. Fink showed in 1994 that for any directed tree T with m arcs, the dir...

In this paper, we consider special class of trees called uniform k-distant trees, which have many interesting properties. We show that they have an edge-magic total labeling, a super edge-magic total labeling, a (a, d)-edge-antimagic vertex labeling, an (a, d)-edgeantimagic total labeling, a super (a, d)edge-antimagic total labeling. Also we introduce a new labeling called edge bi-magic vertex ...

A graph X is max-λ if λ(X) = δ(X). A graph X is super-λ if X is max-λ and every minimum edge-cut set of X isolates one vertex. In this paper, we proved that for all but a few exceptions, the mixed Cayley graph which is defined as a new kind of semi-regular graph is max-λ and super-λ. c © 2008 Elsevier B.V. All rights reserved.

Let A be an abelian group. An A-magic of a graph G = (V, E) is a labeling l : E(G) → A \ {0} such that the sum of the labels of the edges incident with u ∈ V is a constant, where 0 is the identity element of the group A. In this paper, we will show that some classes of graphs are A-magic for all abelian group A of even order other than 2. Also, we prove that product and composition of A-magic g...

A graph G of order n is called arbitrarily vertex decomposable if for each sequence (n1, . . . , nk) of positive integers such that ∑k i=1 ni = n, there exists a partition (V1, . . . , Vk) of vertex set of G such that for every i ∈ {1, . . . , k} the set Vi induces a connected subgraph of G on ni vertices. We consider arbitrarily vertex decomposable unicyclic graphs with dominating cycle. We al...

In this paper we present an algorithm and prove the existence of graph labelings such as Z 3 -magic, Cordial, total cordial, E-cordial, total E-cordial, Product cordial, total product cordial, Product E-cordial, total product E-cordial labelings for the Competition graph of the Cayley digraphs associated with the diheadral group D n . AMS SUBJECT CLASSIFICATION: 05C78.