Hierarchies and Classifications of Sets 1

For simplicity, we follow the rules: A denotes a relational structure, X denotes a non empty set, P1, P2, P3, Y , a, b, c, x denote sets, and S1 denotes a subset of Y . Let us consider A. We say that A has superior elements if and only if: (Def. 1) There exists an element of A which is superior of the internal relation of A. Let us consider A. We say that A… (More)