Some path unions invariance under cordial labeling

Abstract

In this paper we define some new path unions, obtain different path unions from same graph and show them to be invariant under cordial labelings. i.e. we actually obtain cordial labeling of these different structures. We define bull graph and show that Path union of bull graph G = pm(C3bull) all three non isomorphic structures, Path union of C4 bull graph (G = pm(C4bull) all three non isomorphic structures, Path union of C3+ all two structures, Path union of C+4-e all five structures are cordial graphs.