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CS486 Spring 1997
Lecture 20 Tuesday, April 8, 1997
Reading
Project: Please hand in some ideas for projects on Thursday, April 10.
- Set Theory continued
- overview: defining natural numbers as first step in defining the reals, need for well-ordering
- ordering relations and well-ordering
- axiomatic account of Cartesian product,
as 
- use of power set axiom
- definition of function space,
(like 
) need 
- Natural numbers in set theory
- definition of
(same as 
) and ordinals
- axiom of infinity needed
- recursively defined functions
- proving the induction principle on (Thm 22)-next time
- Comparing accounts of numbers, and pairs and functions