Fault-tolerant extensions of complete multipartite networks

The authors studied the design of a fault-tolerant extension for a graph G which can survive at most m node failures, and which contains the minimum number of nodes and the fewest possible edges when the nonredundant graph (G) is a complete multipartite graph. After developing a characterization for m-fault-tolerant extensions and for optimal m-fault-tolerant extensions of a complete multipartite graph, this characterization is used to develop a procedure to construct an optimal m-fault-tolerant extension of any complete multipartite graph, for any m⩾0. The procedure is only useful when the size of the graph is relatively small, since the search time required is exponential. Several necessary conditions on any (optimal) m-fault-tolerant extension of a complete multipartite graph are proved. These conditions allow identification of some optimal m-fault-tolerant extensions of several special cases of a complete multipartite graph without performing any search