Math 504 Homework 1 due Sept. 4

John Baldwin

August 28, 1998

1. Kunen problem 1. Write a formula expressing z = ⟨⟨x, y⟩⟨v, w⟩⟩ using only ∈ and =.

2. Write formulas in set theory expressing the definition of function, onto, 1-1. (Stop when you are bored).

3. Write a formula of set theory which holds of a set a if and only if a is infinite.