Every nonempty set has an epsilon minimal and an epsilon maximal element. Separation for bounded formulas. Every set is in one-one correspondence with an ordinal. And again we can optionally add 8. There is a least set containing all elements of any given set.
Every nonempty set has an epsilon minimal and an epsilon maximal element.
Separation for bounded formulas. Every set is in one-one correspondence with an ordinal. The cumulative hierarchy exists on every ordinal. We can optionally add 8. The cumulative hierarchy exists on every ordinal and exhausts every set.