Bases of ZF0-models
Tóm tắt
In this paper we want to describe the structure of certain ZF0-models (ZF0=ZF minus foundation). For this there will be introduced the notions of a base and a minimal base of a ZF0-model. We shall see, whether the existence of a definable (minimal) base is consistent with various axioms of universality. Necessary and sufficient conditions for the definability of a — minimal — base are given.
Tài liệu tham khảo
v. Rimscha, M.: Universality and strong extensionality. Arch. math. Logik21, 179–193 (1981).
v. Rimscha, M.: Weak foundation and axioms of universality. Arch. math. Logik21, 195–205 (1981).