Parameterized Complexity

This monograph presents an approach to complexity theory which offers a means of analysing algorithms in terms of their tractability. This will be suitable for graduate students and researchers in computer science and mathematics, particularly those studying complexity theory.

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The idea for this book was conceived over the second bottle of Villa Maria's Caber­ net Medot '89, at the dinner of the Australasian Combinatorics Conference held at Palmerston North, New Zealand in December 1990, where the authors first met and discovered they had a number of interests in common. Initially, we embarked on a small project to try to formulate reductions to address the apparent parame­ terized intractability of DOMINATING SET, and to introduce a structure in which to frame our answers. Having spent several months trying to get the definitions for the reductions right (they now seem so obvious), we turned to our tattered copies of Garey and Johnson's work [239]. We were stunned to find that virtually none of the classical reductions worked in the parameterized setting. We then wondered if we'd be able to find any interesting reductions. Several years, many more bottles, so many papers, and reductions later it [3] seemed that we had unwittingly stumbled upon what we believe is a truly central and new area of complexity theory. It seemed to us that the material would be of great interest to people working in areas where exact algorithms for a small range of parameters are natural and useful (e. g. , Molecular Biology, VLSI design). The tractability theory was rich with distinctive and powerful techniques. The intractability theory seemed to have a deep structure and techniques all of its own.

Résumé
An approach to complexity theory which offers a means of analysing algorithms in terms of their tractability. The authors consider the problem in terms of parameterized languages and taking "k-slices" of the language, thus introducing readers to new classes of algorithms which may be analysed more precisely than was the case until now.

Contenu
1 Computers, Complexity, and Intractability from the Parametric Point of View.- 1.1 Introduction.- 1.2 The Role of Computational Complexity in Modern Science.- 1.3 The Story of Dr.O, Continued.- 1.4 Reworking the Foundations of Computational Complexity.- 1.5 A Deal with the Devil.- 1.6 How Parameters Arise in Practice.- 1.7 A Distinctive Positive Toolkit.- 1.8 O No?.- 1.9 The Barometer of Parametric Intractability.- 1.10 Structural Aspects of Parameterized Complexity.- 1.11 An Overview of Current Research Horizons.- I Parameterized Tractability.- 2 The Basic Definitions.- 3 Some Ad Hoc Methods: The Methods of Bounded Search Tree and Problem Kernel.- 4 Optimization Problems, Approximation Schemes, and Their Relation with FPT.- 5 The Advice View Revisited and LOGSPACE.- 6 Methods via Automata and Bounded Treewidth.- 7 Well-Quasi-Orderings and the Robertson-Seymour Theorems.- 8 Miscellaneous Techniques.- II Parameterized Intractability.- 9 Reductions.- 10 The Basic Class W[1] and an Analog of Cook's Theorem.- 11 Some Other W[1]-Hardness Results.- 12 The W -Hierarchy.- 13 Beyond W[t]-Hardness.- 14 Fixed Parameter Analogs of PSPACE and k-Move Games.- 15 Provable Intractability: The Class XP.- III Structural and Other Results.- 16 Another Basis for the W -Hierarchy, the Tradeoff-Theorem, and Randomized Reductions.- 17 Relationships with Classical Complexity and Limited Nondeterminism.- 18 The Monotone and Antimonotone Collapse Theorems: MONOTONEW[2t + 1] = W[2t] and ANTIMONOTONEW[2t + 2] = W[2t + 1].- 19 The Structure of Languages Under Parameterized Reducibilities.- IV Appendix.- A A Problem Compendium and Guide to W-Hierarchy Completeness, Hardness, and Classification; and Some Research Horizons.- B Research Horizons.- B.2 A Lineup of Tough Customers.- B.3 ConnectionsBetween Classical and Parameterized Complexity.- B.4 Classification Gaps.- B.5 Structural Issues and Analogs of Classical Results.- References.