Using argument strength for building dialectical bonsai

SEBASTIÁN GOTTIFREDI; NICOLÁS D. ROTSTEIN; ALEJANDRO J. GARCÍA; GUILLERMO R. SIMARI

ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE

SPRINGER

Lugar: Berlin; Año: 2013 vol. 69 p. 103 - 129

1012-2443

Argumentation in AI provides an inconsistency-tolerant formalism capa- ble of establishing those pieces of knowledge that can be accepted despite having information in contradiction. Computation of accepted arguments tends to be expen- sive; in order to alleviate this issue, we propose a heuristics-based pruning technique over argumentation trees. Empirical testing shows that in most cases our approach answers queries much faster than the usual techniques, which prune with no guide. Theheuristicsisbasedonameasureofstrengthassignedtoarguments.Weshowhow to compute these strength values by providing the corresponding algorithms, which use dynamic programming techniques to reutilise previously computed trees. In addition to this, we introduce a set of postulates characterising the desired behaviour of any strength formula. We check the given measure of strength against these postulates to show that its behaviour is rational. Although the approach presented here is based on an abstract argumentation framework, the techniques are tightly connected to the dialectical process rather than to the framework itself. Thus, results can be extrapolated to other dialectical-tree-based argumentation formalisms with no additional difficulty.