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TeenieBopper
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Homework Statement
Suppose that A and B are both countably infinite sets. Prove that there is a one to one correspondence between A and B.
Homework Equations
The Attempt at a Solution
By definition of countably infinite, there is a one to one correspondence between Z+ and A and Z+ and B.
Let n ε Z+. All elements of A and B can be listed as follows
A = a1, a2, a3, ... , an
B = b1, b2, b3, ... , bn
I was going to say that if f(n) = an and f(n) = bn, then an = bn, but f:Z -> A by x and f: Z -> B by x^2 makes this invalid. I know that because A and B are both countably infinite, they are cardinally equivalent, and that if they are cardinally equivalent, then there exists a one to one correspondence between the two sets, but I can't seem to get the proof.