ABSTRACT: The unit circle is the universal basis for the trigonometric functions on the two-dimensional plane. It is applied to analyze the paradoxical internal structure of a universal state, the 1-D ...

But with the axioms we have given, we see every Grothendieck universe is a model for ZF set theory. {{{book-title(Set Theory: The Third Millennium Edition, revised and expanded)}}}. \ Springer, 2003.

The natural numbers are defined recursively by letting 0 = {} be the empty set. n + 1 = n u {n} for each n Membership - does an item belong to a set? Must be unambiguous. Uppercase letters for sets, ...