\input zb-basic \input zb-ioport \iteman{io-port 00975331} \itemau{Kubicki, Grzegorz} \itemti{Greatest common subgraph index of graphs.} \itemso{Congr. Numerantium 76, 101-113 (1990).} \itemab Summary: A greatest common subgraph (gcs) of a family of graphs, all of the same size, is a graph of maximum size that is a common subgraph of every graph in this family. The gcs index of a graph $G$ is the largest integer $q$ such that there exists a family of graphs (all of size $q)$ with the property that $G$ is its unique gcs. Lower bounds for the gcs index are given. A sufficient condition for a graph to have infinite gcs index is presented. \itemrv{~} \itemcc{} \itemut{greatest common subgraph; index} \itemli{} \end