Logics for Modally Real and Modally Nonreal Events

Studies in Logic, Vol. 16, No. 3 (2023): 108–118       PII: 1674­3202(2023)­03­0108­11

Xian Zhao       Tianqun Pan

An event is modally real in one world if it occurs either in the world or in one of its possible worlds; accordingly, an event is modally nonreal in one world if it does not occur in the world or in any one of its possible worlds. We call a place where all modally nonreal events of a world occur or exist as a modally black hole. This paper presents logical systems for modally real events and modally nonreal events, proves their soundness, and establishes their completeness.