Gutman index - a critical personal account

Ivan Gutman

In the recent literature there are numerous publications concerned with a graph invariant named ``{ı Gutman index}'' ($\mathit{ZZ}$). In this paper, some details about the discovery of $\mathit{ZZ}$ are explained. In particular, it is pointed out that the name for $\mathit{ZZ}$ is a result of negligence, caused by a sloppy reading of the article in which $\mathit{ZZ}$ was mentioned for the first time. The main mathematical properties of $\mathit{ZZ}$ are presented. The reasons why $\mathit{ZZ}$ became popular among scholars doing research in graph theory and mathematical chemistry are discussed, and the practical applicability of $\mathit{ZZ}$ (which is minor) commented.