• Publications
  • Influence
The Computational Structure of Monotone Monadic SNP and Constraint Satisfaction: A Study through Datalog and Group Theory
This paper isolates a class (of problems specified by) "monotone monadic SNP without inequality" which may exhibit a dichotomy, and explains the placing of all these restrictions by showing, essentially using Ladner's theorem, that classes obtained by using only two of the above three restrictions do not show this dichotomy. Expand
The benefits of relaxing punctuality
A temporal language is introduced that can constrain the time difference between events only with finite (yet arbitrary) precision and show the resulting logic to be EXPACE-complete, allowing the authors to develop an algorithm for the verification of timing properties of real time systems with a dense semantics. Expand
The Benefits of Relaxing Punctuality
This work introduces a temporal language that can constrain the time difference between events only with finite, yet arbitrary, precision and show the resulting logic to be EXPSPACE-complete. Expand
Optimal algorithms for approximate clustering
This work gives a polynomial time approximation scheme that estimates the optimal number of clusters under the second measure of cluster size within factors arbitrarily close to 1 for a fixed cluster size. Expand
Balanced matroids
Achieving anonymity via clustering
This is the first set of algorithms for the anonymization problem where the performance is independent of the anonymity parameter k, and extends the algorithms to allow an ε fraction of points to remain unclustered, i.e., deleted from the anonymized publication. Expand
Anonymizing Tables
It is shown that the k-Anonymity problem is NP-hard even when the attribute values are ternary, and an O(k)-approximation algorithm is provided for the problem, which improves upon the previous best-known O( klog k)- approximation. Expand
A New Fixed Point Approach for Stable Networks and Stable Marriages
  • T. Feder
  • Computer Science
  • J. Comput. Syst. Sci.
  • 1 October 1992
This approach builds on structural properties of these networks and exposes close ties with the theory of retracts and isometric embeddings for product graphs, which gives new efficient algorithms for questions of representation, enumeration, and optimization in stable matching. Expand
List Homomorphisms to Reflexive Graphs
  • T. Feder, P. Hell
  • Mathematics, Computer Science
  • J. Comb. Theory, Ser. B
  • 1 March 1998
A polynomial time algorithm is given to solve the problem when the input graph is an interval graph and it is argued that the complexity of certain other modifications of the problem are likely to be difficult to classify. Expand
Clique partitions, graph compression and speeding-up algorithms
The notion of a compression of a graph ~ is defined and used to efficiently compute an optimal compression for graphs of a given size to improve upon the running times of the best-known algorithms for these problems. Expand