Graph minors. V. Excluding a planar graph
Journal of Combinatorial Theory Series B
Fixed-parameter tractability and completeness II: on completeness for W[1]
Theoretical Computer Science
On the complexity of database queries (extended abstract)
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Conjunctive-query containment and constraint satisfaction
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Hypertree decompositions and tractable queries
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Conjunctive Query Containment Revisited
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Perspectives on database theory
FOCS '95 Proceedings of the 36th Annual Symposium on Foundations of Computer Science
The Complexity of Acyclic Conjunctive Queries
FOCS '98 Proceedings of the 39th Annual Symposium on Foundations of Computer Science
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Parameterized Complexity
The parameterized complexity of database queries
PODS '01 Proceedings of the twentieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Robbers, marshals, and guards: game theoretic and logical characterizations of hypertree width
PODS '01 Proceedings of the twentieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Query evaluation via tree-decompositions
Journal of the ACM (JACM)
Hypertree Decompositions: A Survey
MFCS '01 Proceedings of the 26th International Symposium on Mathematical Foundations of Computer Science
Generalized Model-Checking Problems for First-Order Logic
STACS '01 Proceedings of the 18th Annual Symposium on Theoretical Aspects of Computer Science
A Parametric Analysis of the State Explosion Problem in Model Checking
STACS '02 Proceedings of the 19th Annual Symposium on Theoretical Aspects of Computer Science
Describing Parameterized Complexity Classes
STACS '02 Proceedings of the 19th Annual Symposium on Theoretical Aspects of Computer Science
Solving Order Constraints in Logarithmic Space
STACS '03 Proceedings of the 20th Annual Symposium on Theoretical Aspects of Computer Science
Robbers, marshals, and guards: game theoretic and logical characterizations of hypertree width
Journal of Computer and System Sciences - Special issu on PODS 2001
Tree-width and the monadic quantifier hierarchy
Theoretical Computer Science - Logic and complexity in computer science
Describing parameterized complexity classes
Information and Computation
Weighted hypertree decompositions and optimal query plans
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On preservation under homomorphisms and unions of conjunctive queries
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The complexity of counting homomorphisms seen from the other side
Theoretical Computer Science
Datalog programs and their persistency numbers
ACM Transactions on Computational Logic (TOCL)
Query answering exploiting structural properties
ACM SIGMOD Record
Constraint solving via fractional edge covers
SODA '06 Proceedings of the seventeenth annual ACM-SIAM symposium on Discrete algorithm
On preservation under homomorphisms and unions of conjunctive queries
Journal of the ACM (JACM)
A parametric analysis of the state-explosion problem in model checking
Journal of Computer and System Sciences
The complexity of homomorphism and constraint satisfaction problems seen from the other side
Journal of the ACM (JACM)
Weighted hypertree decompositions and optimal query plans
Journal of Computer and System Sciences
Towards a dichotomy theorem for the counting constraint satisfaction problem
Information and Computation
Approximating fractional hypertree width
SODA '09 Proceedings of the twentieth Annual ACM-SIAM Symposium on Discrete Algorithms
A Logical Approach to Constraint Satisfaction
Complexity of Constraints
Uniform Constraint Satisfaction Problems and Database Theory
Complexity of Constraints
Approximating fractional hypertree width
ACM Transactions on Algorithms (TALG)
IWPEC'08 Proceedings of the 3rd international conference on Parameterized and exact computation
Database theory: query languages
Algorithms and theory of computation handbook
Structural tractability of enumerating CSP solutions
CP'10 Proceedings of the 16th international conference on Principles and practice of constraint programming
The complexity of evaluating tuple generating dependencies
Proceedings of the 14th International Conference on Database Theory
Foundations of Semantic Web databases
Journal of Computer and System Sciences
Logics for unranked trees: an overview
ICALP'05 Proceedings of the 32nd international conference on Automata, Languages and Programming
Computing hypergraph width measures exactly
Information Processing Letters
Efficient approximations of conjunctive queries
PODS '12 Proceedings of the 31st symposium on Principles of Database Systems
Factorised representations of query results: size bounds and readability
Proceedings of the 15th International Conference on Database Theory
Entangled queries: Enabling declarative data-driven coordination
ACM Transactions on Database Systems (TODS)
Decomposing Quantified Conjunctive (or Disjunctive) Formulas
LICS '12 Proceedings of the 2012 27th Annual IEEE/ACM Symposium on Logic in Computer Science
On acyclic conjunctive queries and constant delay enumeration
CSL'07/EACSL'07 Proceedings of the 21st international conference, and Proceedings of the 16th annuall conference on Computer Science Logic
Structural tractability of counting of solutions to conjunctive queries
Proceedings of the 16th International Conference on Database Theory
The fine classification of conjunctive queries and parameterized logarithmic space complexity
Proceedings of the 32nd symposium on Principles of database systems
Block-Sorted quantified conjunctive queries
ICALP'13 Proceedings of the 40th international conference on Automata, Languages, and Programming - Volume Part II
Ontology-based data access with databases: a short course
RW'13 Proceedings of the 9th international conference on Reasoning Web: semantic technologies for intelligent data access
The complexity of weighted counting for acyclic conjunctive queries
Journal of Computer and System Sciences
On the complexity of existential positive queries
ACM Transactions on Computational Logic (TOCL)
| Hi-index | 0.02 |
The evaluation of conjunctive queries is hard both with respect to its combined complexity (NP-complete) and its parameterized complexity (W[1]-complete). It becomes tractable (PTIME for combined complexity, FPT for parameterized complexity), when the underlying graphs of the conjunctive queries have bounded tree-width [2]. We show that, in some sense, this is optimal both with respect to combined and parameterized complexity: For every class C of graphs, the evaluation of all conjunctive queries whose underlying graph is in C is tractable if, and only if, C has bounded tree-width.A technical result of independent interest is that the colored grid homomorphism problem is NP-complete and, if parameterized by the grid size, W[1]-complete.