Abduction and beyond in logic programming with application to morality. Accepted

In this paper we emphasize two different aspects of abduction in Logic Pro-gramming (LP): (1) the engineering of LP abduction systems, and (2) appli-cation of LP abduction, complemented with other non-monotonic features, to model morality issues. For the LP engineering part, we present an implemented tabled abduction technique in order to reuse priorly obtained (and tabled) ab-ductive solutions, from one abductive context to another. Aiming at the inter-play between LP abduction and other LP non-monotonic reasoning, this tabled abduction technique is combined with our own-developed LP updating mecha-nism – the latter also employs tabling mechanisms, notably incremental tabling of XSB Prolog. The first contribution of this paper is therefore a survey of our tabled abduction and updating techniques, plus further development of our preliminary approach to combine these two techniques. The second contribution of the paper pertains to the application part. We formulate a LP-based counterfactual reasoning, based on Pearl’s structural the