Rapporto tecnico, 2021, ENG

Situated conditional reasoning

Casini G.; Meyer T.; Varzinczak I.

CNR-ISTI, Pisa, Italy - University of Cape Town, Cape Town, South Africa e CAIR, South Africa; CRIL, University of Cape Town, Cape Town, South Africa - CAIR, South Africa e CNR-ISTI, Pisa, Italy; CRIL, Univ. Artois & CNRS, France - Stellenbosch University, South Africa - CAIR, South Africa e CNR-ISTI, Pisa, Italy

Conditionals are useful for modelling, but aren't always sufficiently expressive for capturing information accurately. In this paper we make the case for a form of conditional that is situation-based. These conditionals are more expressive than classical conditionals, are general enough to be used in several application domains, and are able to distinguish, for example, between expectations and counterfactuals. Formally, they are shown to generalise the conditional setting in the style of Kraus, Lehmann, and Magidor. We show that situation-based conditionals can be described in terms of a set of rationality postulates. We then propose an intuitive semantics for these conditionals, and present a representation result which shows that our semantic construction corresponds exactly to the description in terms of postulates. With the semantics in place, we proceed to define a form of entailment for situated conditional knowledge bases, which we refer to as minimal closure. It is reminiscent of and, indeed, inspired by, the version of entailment for propositional conditional knowledge bases known as rational closure. Finally, we proceed to show that it is possible to reduce the computation of minimal closure to a series of propositional entailment and satisfiability checks. While this is also the case for rational closure, it is somewhat surprising that the result carries over to minimal closure.

Keywords

Conditional reasoning, Non-monotonic reasoning, Counterfactual reasoning, Defeasible reasoning, Belief change

CNR authors

Meyer Thomas Andreas, Varzinczak Ivan, Casini Giovanni

CNR institutes

ISTI – Istituto di scienza e tecnologie dell'informazione "Alessandro Faedo"

ID: 459191

Year: 2021

Type: Rapporto tecnico

Creation: 2021-11-19 11:41:05.000

Last update: 2022-02-14 13:07:45.000

External links

OAI-PMH: Dublin Core

OAI-PMH: Mods

OAI-PMH: RDF

URL: https://doi.org/10.32079/ISTI-TR-2021/009

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:459191