Luis E. Sanchis 
Set Theory-An Operational Approach 
An Operational Approach

This volume presents a novel approach to set theory that is entirely operational. This approach avoids the existential axioms associated with traditional Zermelo-Fraenkel set theory, and provides both a foundation for set theory and a practical approach to learning the subject. It is written at the professional/graduate student level, and will be of interest to mathematical logicians, philosophers of mathematics and students of theoretical computer science.