... minimalr-twin-free graph for the induced subgraph relationship. Indeed, we have:the electronic journal of combinatorics 15 (2008), #N17 5An r-twin-free graph contains a path P2r+1as an induced ... vertices. Let VHbe the vertex- set of H.There exists in H a vertex vtwhich is not a cutvertex; by minimality of H, the con-nected induced subgraph H[VH−vt] of H must have radius at most ... vertices in graphs, IEEE Transactions on Information Theory, vol 44, pp.599-611, 1998.[6] A. Lobstein, Bibliography on identifying and locating-dominating codes in graphs,http://www.infres.enst.fr/∼lobstein/debutBIBidetlocdom.pdf[7]...