2019-04-01: Johannes Marti (Universität Bremen)

Tue, 14 Oct 2025 16:51:42 +0000

Johannes Marti (Universität Bremen)

Determinacy and the red-green chase

Abstract

The determinacy problem is to decide for queries v₁,...,vn and q whether for every database D knowing the answers to v₁,...,vn in D suffices to deduce the answer to q in D. It has been shown that this problem is undecidable if v₁,...,vn and q are arbitrary conjunctive queries.

In this talk I give a gentle introduction to some of the formal tools that are used to study the determinacy problem. Especially, I focus on the red-green chase, which is a neat construction that links the problem of determinacy with query answering relative to ontologies. Lastly, I might present some of our own, very modest, results about classes of conjunctive queries for which the determinacy problem is decidable.

2019-04-01 16:00:00 UTC
LT1310