Is the Standard Proof System for SAT P-Optimal?
FST TCS 2000 Proceedings of the 20th Conference on Foundations of Software Technology and Theoretical Computer Science
The Complexity of Maximum Matroid-Greedoid Intersection
FCT '01 Proceedings of the 13th International Symposium on Fundamentals of Computation Theory
The Difficulty of Reduced Error Pruning of Leveled Branching Programs
Annals of Mathematics and Artificial Intelligence
On the complexity of vertex-disjoint length-restricted path problems
Computational Complexity
The complexity of maximum matroid-greedoid intersection and weighted greedoid maximization
Discrete Applied Mathematics - Special issue: Efficient algorithms
Completeness in approximation classes beyond APX
Theoretical Computer Science
Boolean Constraint Satisfaction Problems: When Does Post's Lattice Help?
Complexity of Constraints
Nondeterministic functions and the existence of optimal proof systems
Theoretical Computer Science
The complexity of maximum matroid-greedoid intersection and weighted greedoid maximization
Discrete Applied Mathematics - Special issue: Efficient algorithms
Logspace optimization problems and their approximability properties
FCT'05 Proceedings of the 15th international conference on Fundamentals of Computation Theory
Average-case non-approximability of optimisation problems
FCT'05 Proceedings of the 15th international conference on Fundamentals of Computation Theory
Differential approximation of MIN SAT, MAX SAT and related problems
ICCSA'05 Proceedings of the 2005 international conference on Computational Science and Its Applications - Volume Part IV
Survey: A survey on the structure of approximation classes
Computer Science Review
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The study of the approximability properties of NP-hard optimization problems has recently made great advances mainly due to the results obtained in the field of proof checking. The last important breakthrough proves the APX-completeness of several important optimization problems and thus reconciles "two distinct views of approximation classes: syntactic and computational" [S. Khanna et al., in Proc. 35th IEEE Symp. on Foundations of Computer Science, IEEE Computer Society Press, Los Alamitos, CA, 1994, pp. 819--830]. In this paper we obtain new results on the structure of several computationally-defined approximation classes. In particular, after defining a new approximation preserving reducibility to be used for as many approximation classes as possible, we give the first examples of natural NPO-complete problems and the first examples of natural APX-intermediate problems. Moreover, we state new connections between the approximability properties and the query complexity of NPO problems.