Logic programming as constructivism: a formalization and its application to databases
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The expressive power of stratified logic programs
Information and Computation
Fundamental properties of deterministic and nondeterministic extensions of Datalog
Selected papers of the workshop on Deductive database theory
Datalog extensions for database queries and updates
Journal of Computer and System Sciences
The well-founded semantics for general logic programs
Journal of the ACM (JACM)
Equivalence of datalog queries is undecidable
Journal of Logic Programming
The alternating fixpoint of logic programs with negation
PODS '89 Selected papers of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Bottom-up evaluation and query optimization of well-founded models
Theoretical Computer Science
Relational transducers for electronic commerce
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Non-deterministic languages to express deterministic transformations
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Annals of Mathematics and Artificial Intelligence
Total and Partial Well-Founded Datalog Coincide
ICDT '97 Proceedings of the 6th International Conference on Database Theory
A Natural Semantics for Logic Programs with Negation
Proceedings of the Ninth Conference on Foundations of Software Technology and Theoretical Computer Science
Transformation-based bottom-up computation of the well-founded model
Theory and Practice of Logic Programming
Communications of the ACM - Scratch Programming for All
Parallel evaluation of conjunctive queries
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
A rule-based language for web data management
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Relational transducers for declarative networking
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Deciding eventual consistency for a simple class of relational transducer networks
Proceedings of the 15th International Conference on Database Theory
LogicBlox, platform and language: a tutorial
Datalog 2.0'12 Proceedings of the Second international conference on Datalog in Academia and Industry
Datalog 2.0'12 Proceedings of the Second international conference on Datalog in Academia and Industry
Relational transducers for declarative networking
Journal of the ACM (JACM)
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In a recent paper by Hellerstein [15], a tight relationship was conjectured between the number of strata of a Datalog¬ program and the number of "coordination stages" required for its distributed computation. Indeed, Ameloot et al. [9] showed that a query can be computed by a coordination-free relational transducer network iff it is monotone, thus answering in the affirmative a variant of Hellerstein's CALM conjecture, based on a particular definition of coordination-free computation. In this paper, we present three additional models for declarative networking. In these variants, relational transducers have limited access to the way data is distributed. This variation allows transducer networks to compute more queries in a coordination-free manner: e.g., a transducer can check whether a ground atom A over the input schema is in the "scope" of the local node, and then send either A or ¬A to other nodes. We show the surprising result that the query given by the well-founded semantics of the unstratifiable win-move program is coordination-free in some of the models we consider. We also show that the original transducer network model [9] and our variants form a strict hierarchy of classes of coordination-free queries. Finally, we identify different syntactic fragments of Datalog∀¬¬, called semi-monotone programs, which can be used as declarative network programming languages, whose distributed computation is guaranteed to be eventually consistent and coordination-free.