Datalog+/-: A Family of Logical Knowledge Representation and Query Languages for New Applications

Modelling Structured Domains Using Description Graphs and Logic Programming

“…This, however, is not the case, since interpretation I does not satisfy axiom (3). One might preclude the existence of extra atoms by adding cardinality restrictions requiring each cyclobutane to have exactly four atoms.…”

“…This problem is similar to reasoning about datalog programs with existentially quantified rule heads (known as tuple-generating dependencies or tgds) [3]. For such programs, conditions such as weak acyclicity [4] or super-weak acyclicity [11] ensure the termination of bottom-up reasoning algorithms: these conditions examine the syntactic structure of the rules and check whether values created by a rule's head can be propagated so as to eventually satisfy the premise of the same rule.…”

“…A common solution to this problem is to extend OWL 2 with a rule-based formalism such as SWRL; 3 however, this either results in undecidability [9] or requires restrictions in the shape of the rules [8], which typically prevent the rules from axiomatising the required structures. An alternative approach suggests a combination of OWL 2, rules, and description graphs (DGs) [12]-a graphical notation for describing non-tree-like structures.…”

Uniform Evaluation of Nonmonotonic DL-Programs

“…As test ontology we used an EL variant of Galen, 6 a large biomedical ontology. 7 In the test, we created four ontology instances G 1 to G 4 that have a fixed Galen TBox and increasing ABoxes with 10i assertions, each using roughly ten concepts and roles. We performed four instance retrieval queries over G i : (i) q 1 (X) = Substance(X), (ii) q 2 (X) = Animal (X), (iii) q 3 (X) = MaleAdult(X), and (iv) q 4 (X) = Human(X).…”

“…But also formalisms for which reasoning engines are yet emerging might be of interest, e.g. Datalog ± [7]. The latter extends Datalog with existential quantification in rule head and at the same time restricts the syntax such that reasoning remains decidable.…”