let $g=(v,e)$ be a connected simple graph. a labeling $f:v to z_2$ induces two edge labelings $f^+, f^*: e to z_2$ defined by $f^+(xy) = f(x)+f(y)$ and $f^*(xy) = f(x)f(y)$ for each $xy in e$. for $i in z_2$, let $v_f(i) = |f^{-1}(i)|$, $e_{f^+}(i) = |(f^{+})^{-1}(i)|$ and $e_{f^*}(i) = |(f^*)^{-1}(i)|$. a labeling $f$ is called friendly if $|v_f(1)-v_f(0)| le 1$. for a friendly labeling $f$ of...

A binary vertex coloring (labeling) f : V (G) → Z2 of a graph G is said to be friendly if the number of vertices labeled 0 is almost the same as the number of vertices labeled 1. This friendly labeling induces an edge labeling f∗ : E(G) → Z2 defined by f∗(uv) = f(u)f(v) for all uv ∈ E(G). Let ef (i) = |{uv ∈ E(G) : f∗(uv) = i}| be the number of edges of G that are labeled i. Product-cordial ind...

I.Cahit introduced cordial graphs as a weaker version of graceful and harmonious graphs. The total product cordial labeling is a variant of cordial labeling. In this paper we introduce a vertex analogue product cordial labeling as a variant of total product cordial labeling and name it as total vertex product cordial labeling. Finally, we investigate total vertex product cordial labeling for ma...

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.

For a graph G = (V,E) with a binary vertex coloring f : V (G)→ Z2, let vf (i) = |f−1(i)|. We say f is friendly if |vf (1) − vf (0)| ≤ 1, i.e., the number of vertices labeled 1 is the same or almost the same as the number of vertices labeled 0. The coloring f induces an edge labeling f ∗ : E(G) → Z2 defined by f ∗(uv) = f(u) + f(v) (mod 2), for each uv ∈ E(G). Let ef (i) = |{uv ∈ E(G) : f ∗(uv) ...

In this paper, we show that the disjoint union of two cordial graphs one of them is of even size is cordial and the join of two cordial graphs both are of even size or one of them is of even size and one of them is of even order is cordial. We also show that Cm∪ Cn is cordial if and only if m+n ≡/ 2 (mod 4) and mCn is cordial if and only if mn ≡/ 2 (mod 4) and for m, n ≥ 3, Cm + Cn is cordial i...

We calculate the cordial edge deficiencies of the complete multipartite graphs and find an upper bound for their cordial vertex deficiencies. We also give conditions under which the tensor product of two cordial graphs is cordial.

A k-total edge product cordial labeling is a variant of the well-known cordial labeling. In this paper we characterize graphs admitting a 2total edge product cordial labeling. We also show that dense graphs and regular graphs of degree 2(k − 1) admit a k-total edge product cordial labeling.

Hovey introduced A-cordial labelings in [4] as a simultaneous generalization of cordial and harmonious labelings. If A is an abelian group, then a labeling f : V (G) → A of the vertices of some graph G induces an edgelabeling on G; the edge uv receives the label f(u) + f(v). A graph G is A-cordial if there is a vertex-labeling such that (1) the vertex label classes differ in size by at most one...

In this paper we prove that the split graphs of 1,n K and are prime cordial graphs. We also show that the square graph of is a prime cordial graph while middle graph of is a prime cordial graph for . Further we prove that the wheel graph admits prime cordial labeling for . , n n B n  , n n B n P 8 4 n 