Unlike in Prolog, statements of a Datalog program can be stated in any order. Furthermore, Datalog queries on finite sets are guaranteed to terminate, so Datalog does not have Prolog's cut operator. This makes Datalog a fully See more

The boundedness problem for Datalog asks, given a Datalog program, whether it is bounded, i.e., the maximal recursion depth reached when evaluating the program on an input … See more

A Datalog program consists of a list of facts and rules (Horn clauses). If constant and variable are two countable sets of constants and … See more

There are many different ways to evaluate a Datalog program, with different performance characteristics.
Bottom-up evaluation strategies
Bottom-up evaluation strategies start with the facts in the program and repeatedly apply the rules until … See more

Datalog programs may or may not use negation in rule bodies: Datalog programs with negation are often required to use it as stratified negation to ensure that the semantics are well-defined. Datalog programs may or may not use inequalities between variables … See more

These two lines define two facts, i.e. things that always hold:
This is what they mean: xerces is a parent of brooke and … See more

There are three widely-used approaches to the semantics of Datalog programs: model-theoretic, fixed-point, and proof-theoretic, … See more