The project Nomoneg is devoted to reconsidering non-monotonic negation as used in Datalog extensions and in Logic Programming to achieve both, a procedural semantics consisting in a backward chaining procedure and an associated declarative semantics consisting in a Tarski-style model theory.

        A backward chaining procedural semantics is sought for because web-based and/or distributed applications involve too large amounts of data for a purely forward chaining procedural semantics to be effective. Note that approaches like magic sets are understood as backward chaining implemented in forward chaining and therefore are considered in the project.

        A Tarsky-style model theory has a semantic function recursively defined on the formula structures. This is necessary for a declarative semantics to be compositional, that is, to "glue" together model parts determined independently from each other.