Lecture 16 (Computation Theory) Decidability and Undecidability

Two sets A and B are defined to have the same cardinality precisely when:

1. A.A and B each contain only finitely many elements
2. B.There is a bijection f : A → B (a function that is one-to-one and onto)
3. C.Every element of A is also an element of B and vice versa
4. D.There is some injection f : A → B, even if it is not onto