Let f be a map from V(G) to . For each edge uv assign the label . f is called a mean cordial la- beling if and , , where and denote the number of vertices and edges respectively labelled with x ( ). A graph with a mean cordial labeling is called a mean cor- dial graph. We investigate mean cordial labeling behavior of Paths, Cycles, Stars, Complete graphs, Combs and some more standard graphs

Let G be a (p,q) graph. An injective map ƒ: V (G) →{±1, ±2,...,±p} is called a pair sum labeling if the induced edge function, ƒ e : E(G)→Z -{0} defined by ƒ e (uv)=ƒ(u)+ƒ(v) is oneone and ƒ e (E(G)) is either of the form {±k 1 , ±k 2 ,…, ±k q/2 } or {±k 1 , ±k 2 ,…, ±k (q-1)/2 } {k (q+1)/2 } according as q is even or odd. Here we prove that every graph is a subgraph of a connected pair sum graph. Also we investigate the pair sum labeling of some graphs which are obtained from cycles. Finally we enumerate all pair sum graphs of order ≤ 5.

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<p>Let G be a (p, q) graph. Let f : V (G) → {1, 2, . . . , k} be a map where k is an integer 2 ≤ k ≤ p. For each edge uv, assign the label |f(u) − f(v)|. f is called k-difference cordial labeling of G if |vf (i) − vf (j)| ≤ 1 and |ef (0) − ef (1)| ≤ 1 where vf (x) denotes the number of vertices labelled with x, ef (1) and ef (0) respectively denote the number of edges labelled with 1 and not labelled with 1. A graph with a k-difference cordial labeling is called a k-difference cordial graph. In this paper we investigate 3-difference cordial labeling behavior of triangular snake, alternate triangular snake, alternate quadrilateral snake, irregular triangular snake, irregular quadrilateral snake, double triangular snake, double quadrilateral snake, double alternate triangular snake, and double alternate quadrilateral snake.</p>

Let G be a (p, q) graph. Let f be a map from V (G) to {1, 2,. .. , p}. For each edge uv, assign the label |f (u) − f (v)|. f is called a difference cordial labeling if f is a one to one map and e f (0) − e f (1) ≤ 1 where e f (1) and e f (0) denote the number of edges labeled with 1 and not labeled with 1 respectively. A graph with admits a difference cordial labeling is called a difference cordial graph. In this paper, we investigate the difference cordial labeling behavior of triangular snake, Quadrilateral snake, double triangular snake, double quadrilateral snake and alternate snakes. 2010 AMS Mathematics Subject Classification : 05C78.