Application of graph theory in domination of graphs

The access to both serial titles and articles is available via indexes and search forms. They have also been used in document summarization, and in designing secure systems for electrical grids. In , Richard Karp proved the set cover problem to be NP-complete. The interface also provides access to the full text of articles via author index or subject index , or by a search form on article elements such as author names, words from title, subject, words from the full text and publication year. The approximability of set covering is also well understood: a logarithmic approximation factor can be found by using a simple greedy algorithm , and finding a sublogarithmic approximation factor is NP-hard. On the other hand, if the input graph is planar, the problem remains NP-hard, but a fixed-parameter algorithm is known. There are graph families in which a minimum maximal independent set is a minimum dominating set.