Garapa, MarcoFermé, EduardoReis, Maurício D. L.2023-06-142023-06-142023Garapa, M., Fermé, E., & Reis, M. D. (2023). Levi and Harper identities for non-prioritized belief base change. Artificial Intelligence, 319, 103907.http://hdl.handle.net/10400.13/5228In this paper, we investigate the relation between shielded base contraction postulates and credibility-limited (CL) base revision postulates. More precisely, we identify (i) the relation between the postulates satisfied by a shielded base contraction operator and the postulates satisfied by the CL base revision operator that is defined from it by means of the consistency-preserving Levi identity and (ii) the relation between the postulates satisfied by a CL base revision operator and the postulates satisfied by the shielded base contraction operator that is defined from it by means of the Harper identity. Furthermore, we show that the consistency-preserving Levi identity and the Harper identity establish a one-to one correspondence between the twenty classes of shielded base contractions presented in [21] and the twenty classes of credibility-limited base revisions presented in [22].engNon-prioritized belief changeBelief basesBase revisionCredibility-limited base revisionBase contractionConsistency-preserving Levi identityShielded base contractionHarper identity.Faculdade de Ciências Exatas e da Engenhariajournal article10.1016/j.artint.2023.103907