Résumé
Logic based argumentation allows for defeasible reasoning over monotonic logics via grounded semantics or defeasible logic programming (DeLP). We investigate the practical implementation of such techniques for existential rules, a logical language used by many Semantic Web and Ontology Based Data Access applications. Existing tools in the literature (ASPIC+, DeLP) perform poorly for such languages due to their choice of generic reasoning methods using resolution. Since existential rules account for weak negation (as opposed to more general languages) we claim that state of the art argumentation methods (ASPIC+ or DeLP) could be practically outperformed by dedicated forward chaining methods. We analyse this problem from a theoretical point of view, especially with regards to forward chaining issues such as derivation loss, and perform a series of experiments to empirically evaluate our performance claims.