Real and imaginary classes in the alternative set theory
Relative sets and rough sets
In this paper, by defining a pair of classical sets as a relative set, an extension of the classical set algebra which is a counterpart of Belnap's four-valued logic is achieved. Every relative set partitions all objects into four distinct regions corresponding to four truth-values of Belnap's logic. Like truth-values of Belnap's logic, relative sets have two orderings; one is an order of inclusion and the other is an order of knowledge or information. By defining a rough set as a pair of definable...
Relatively constructible transitive models
Remark on a theory of classes used by A. Machado
Remarks In Da Costa's Paraconsistent Set Theories.
Revealed automorphisms
We study automorphisms in the alternative set theory. We prove that fully revealed automorphisms are not closed under composition. We also construct some special automorphisms. We generalize the notion of revealment and Sd-class.
Revealments