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The Data Complexity of Description Logic Ontologies

Carsten Lutz ; Frank Wolter.

We analyze the data complexity of ontology-mediated querying where the ontologies are formulated in a description logic (DL) of the ALC family and queries are conjunctive queries, positive existential queries, or acyclic conjunctive queries. Our approach is non-uniform in the sense that we aim to&nbsp;[&hellip;]

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Modal Logics of Topological Relations

Carsten Lutz ; Frank Wolter.

Logical formalisms for reasoning about relations between spatial regions play a fundamental role in geographical information systems, spatial and constraint databases, and spatial reasoning in AI. In analogy with Halpern and Shoham's modal logic of time intervals based on the Allen relations, we&nbsp;[&hellip;]

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Answer Counting under Guarded TGDs

Cristina Feier ; Carsten Lutz ; Marcin Przybyłko.

We study the complexity of answer counting for ontology-mediated queries and for querying under constraints, considering conjunctive queries and unions thereof (UCQs) as the query language and guarded TGDs as the ontology and constraint language, respectively. Our main result is a classification&nbsp;[&hellip;]

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