Monotone monadic SNP and constraint satisfaction
STOC '93 Proceedings of the twenty-fifth annual ACM symposium on Theory of computing
Closure properties of constraints
Journal of the ACM (JACM)
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On the Structure of Polynomial Time Reducibility
Journal of the ACM (JACM)
Conjunctive-query containment and constraint satisfaction
Journal of Computer and System Sciences - Special issue on the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on principles of database systems
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data Exchange: Semantics and Query Answering
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Constraint Satisfaction Problems and Finite Algebras
ICALP '00 Proceedings of the 27th International Colloquium on Automata, Languages and Programming
View-Based Query Processing and Constraint Satisfaction
LICS '00 Proceedings of the 15th Annual IEEE Symposium on Logic in Computer Science
Tractable conservative Constraint Satisfaction Problems
LICS '03 Proceedings of the 18th Annual IEEE Symposium on Logic in Computer Science
The complexity of satisfiability problems
STOC '78 Proceedings of the tenth annual ACM symposium on Theory of computing
A dichotomy theorem for constraint satisfaction problems on a 3-element set
Journal of the ACM (JACM)
Consistent query answering in databases
ACM SIGMOD Record
Declarative inconsistency handling in relational and semi-structured databases
Declarative inconsistency handling in relational and semi-structured databases
Repair checking in inconsistent databases: algorithms and complexity
Proceedings of the 12th International Conference on Database Theory
Consistent query answers in the presence of universal constraints
Information Systems
Minimal-change integrity maintenance using tuple deletions
Information and Computation
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Relational and XML Data Exchange
Relational and XML Data Exchange
The Dichotomy for Conservative Constraint Satisfaction Problems Revisited
LICS '11 Proceedings of the 2011 IEEE 26th Annual Symposium on Logic in Computer Science
Consistent query answering: five easy pieces
ICDT'07 Proceedings of the 11th international conference on Database Theory
A dichotomy in the complexity of consistent query answering for queries with two atoms
Information Processing Letters
On the data complexity of consistent query answering
Proceedings of the 15th International Conference on Database Theory
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A database may for various reasons become inconsistent with respect to a given set of integrity constraints. To overcome the problem, a formal approach to querying such inconsistent databases has been proposed and since then, a lot of efforts have been spent to classify the complexity of consistent query answering under various classes of constraints. It is known that for the most common constraints and queries, the problem is in coNP and might be coNP-hard, yet several relevant tractable classes have been identified. Additionally, the results that emerged suggested that given a set of key constraints and a conjunctive query, the problem of consistent query answering is either in PTime or is coNP-complete. However, despite all the work, as of today this dichotomy remains a conjecture. The main contribution of this paper is to explain why it appears so difficult to obtain a dichotomy result in the setting of consistent query answering. Namely, we prove that such a dichotomy w.r.t.~common classes of constraints and queries, is harder to achieve than a dichotomy for the constraint satisfaction problem, which is a famous open problem since the 1990s.