New types of integral sum graphs Original Research Article

Harary (Discrete Math. 124(1–3) (1994) 99) introduced the intergral sum graphs, and proved that the path Pn and matching mK2 are integer sum graphs, and offered some conjectures. In this paper we enlarge the types of integral sum graphs. We prove that some caterpillars and mPn are integral sum graphs and some conjectures of Harary are wrong.