Improved algorithms for weakly chordal graphs

Abstract

We use a new structural theorem on the presence of two-pairs in weakly chordal graphs to develop improved algorithms. For the recognition problem, we reduce the time complexity from O( mn 2 ) to O( m 2 ) and the space complexity from O( n 3 ) to O( m + n ), and also produce a hole or antihole if the input graph is not weakly chordal. For the optimization problems, the complexity of the clique and coloring problems is reduced from O( mn 2 ) to O( n 3 ) and the complexity of the independent set and clique cover problems is improved from O( n 4 ) to O( mn ). The space complexity of our optimization algorithms is O( m + n ).