E. Sampathkumar

collaborators

3 papers

math.CO2013

Characterizations of 2-Colorable (Bipartite) and 3-Colorable Graphs

E. Sampathkumar, M. A. Sriraj

A \emph{directional labeling} of an edge $uv$ in a graph $G = (V, E)$ by an ordered pair $ab$ is a labeling of the edge $uv$ such that the label on $uv$ in the direction from $…

math.CO2013

Coloring of a Digraph

E. Sampathkumar

\qquad A \emph{coloring} of a digraph $D = (V, E)$ is a coloring of its vertices following the rule: Let $uv$ be an arc in $D$ . If the tail $u$ is colored first, then the head $v$ sho…

math.CO2013

Directionally 2-Signed and Bidirected Graphs

E. Sampathkumar, M. A. Sriraj, Thomas Zaslavsky

An edge uv in a graph Γ is directionally 2-signed (or, (2,d)-signed) by an ordered pair (a,b), a,b in {+,-}, if the label l(uv) = (a,b) from u to v, and l(vu) = (b,a) from v to u.…