 "Adjunction" implies that if "x" is a set, then so is formula_7.Given "Adjunction", the usual construction of the successor ordinals from the empty set can proceed, one in which the natural numbers are defined as formula_8 (see Peano's axioms).More generally, given any model "M" of ZFC, the collection of hereditarily finite sets in "M" will satisfy the GST axioms.