Aguado, FelicidadCabalar, PedroFandinno, JorgePearce, DavidPérez, GilbertoVidal, Concepción2025-12-102025-12-102020Aguado, F., Cabalar, P., Fandinno, J., Pearce, D., Pérez, G., & Vidal, C. (2021, January). Forgetting auxiliary atoms in forks. In Proceedings of the Twenty-Ninth International Conference on International Joint Conferences on Artificial Intelligence (pp. 5005-5009). https://doi.org/10.24963/ijcai.2020/69697809992411651045-0823https://hdl.handle.net/2183/46634Presented at the Twenty-Ninth International Joint Conference on Artificial Intelligence, Yokohama. 11-17 July 2020, January 2021.[Abstract]: This work tackles the problem of checking strong equivalence of logic programs that may contain local auxiliary atoms, to be removed from their stable models and to be forbidden in any external context. We call this property projective strong equivalence (PSE). It has been recently proved that not any logic program containing auxiliary atoms can be reformulated, under PSE, as another logic program or formula without them -- this is known as strongly persistent forgetting. In this paper, we introduce a conservative extension of Equilibrium Logic and its monotonic basis, the logic of Here-and-There, in which we deal with a new connective we call fork. We provide a semantic characterisation of PSE for forks and use it to show that, in this extension, it is always possible to forget auxiliary atoms under strong persistence. We further define when the obtained fork is representable as a regular formula.eng© 2020 International Joint Conferences on Artificial IntelligenceKnowledge representation and reasoningLogics for knowledge representationNon-monotonic reasoningCommon-sense reasoningKnowledge representation languagesconference outputopen access10.24963/ijcai.2020/696