Irrelevant Updates and Nonmonotonic Assumptions

Irrelevant Updates of Nonmonotonic Knowledge Bases

The second postulate of Katsuno and Mendelzon, 2[KM] hereafter, characterizes irrelevant updates: if ψ implies μ, then ψ μ is equivalent to ψ, where ψ is a knowledge base, μ is an update and is an update operator [3]. We show that the postulate has to be modified, if nonmonotonic assumptions are considered. Our characterization of irrelevant updates is based on a dependency framework [5], which...

Rethinking Semantics of Dynamic Logic Programming

A dynamic logic program represents an evolving knowledge base. Research in the field is dominated by the causal rejection principle: the conflicting rule from the less preferred program is rejected in the case of conflict. Some drawbacks of the causal rejection principle (irrelevant updates, inconsistencies which cannot be solved according to the causal rejection principle, disagreement with ot...

Irrelevant Updates and Self-maintainability in Transitive Closure Views

Irrelevant updates are updates to source data that do not aaect a view deened over the source data. Self-maintainable updates are ones for which the view can be updated, without having to access source data, when the source data from which the view is derived is updated. In this paper we derive necessary and suucient conditions for an update to be irrelevant or self-maintainable when the source...

Relating Database Updates to Nonmonotonic Reasoning

Irrelevant updates and self-maintainability in transitive closure database views

Irrelevant updates in a database are updates to source data that do not affect a view defined over the source data. Selfmaintainable updates are ones for which the view can be updated, without having to access source data, when the source data from which the view is derived is updated. In this paper we derive necessary and sufficient conditions for an update to be irrelevant or self-maintainabl...