We start an investigation into the complexity of variations of the Equal Sum Subsets problem, a basic problem in which we are given a set of numbers and are asked to nd two disjoint subsets of the numbers that add up to the same sum. While Equal Sum Subsets is known to be NP-complete, only very few studies have investigated the complexity of its variations. In this paper, we show NP-completenes...

We develop a general framework of rule based database update on the basis of prioritized logic programs. This approach has advantages in representing and handling information connict in updates. We then focus on the computational aspect of this approach. We show that under our framework, the model checking in an update is co-NP-complete, while the associated inference problem is P 2-complete. F...

We prove the decidability for a class of languages which extend BST and NP-completeness subclass them. The extended with unordered cartesian product, ordered product powerset fall in this last subclass.

In this paper we investigate the potential of interactive visualiza-tion for teaching the theory of NP-completeness to undergraduate students of computer science. Based on this analysis we developed some interactive Java applets which we use to present an NP-complete tiling problem PUZZLE in our lecture. This software is integrated into our hypertext lecture notes and our students also use it t...

The theory of NP-completeness has its roots in a foundational result by Cook, who showed that Boolean satisfiability (SAT) is NP-complete and thus unlikely to admit an efficient solution. We prove an analogous result using binary integer programming in the place of SAT. The proof gives deeper insight into the theory of NP-completeness to operations researchers for whom the language of integer p...

We study the complexity of editing a graph into a target graph with any fixed critical-clique graph. The problem came up in practice, in mining a huge word similarity graph for well structured word clusters. It also adds to the rich field of graph modification problems. We show in a generic way that several variants of this problem are in SUBEPT. As a special case, we give a tight time bound fo...

We prove that it is NP-hard to compute the exact componentwise bounds on solutions of all the linear systems which can be obtained from a given linear system with a nonsingular matrix by perturbing all the data independently of each other within prescribed tolerances.