Let A and B be two sets and let f : A B be a function. Use the Pigeonhole Principle to
Chapter 8, Problem 9(choose chapter or problem)
Let A and B be two sets and let f : A B be a function. Use the Pigeonhole Principle to show that if |A| > |B|, then there exist a1, a2 A such that a1 6= a2 and f(a1) = f(a2) (that is, f is not one-to-one).
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