- #1

snipekiller

- 2

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## Homework Statement

Suppose that |A| = n and |B| = m with n ≤ m. How many one-to-one functions f are possible with f: A → B?

## Homework Equations

If |A| = |B| = m how many different bijections f: A → B are possible?

Answer: m!

## The Attempt at a Solution

I really do not know how to start off the question. If someone can help me get started into this equation that would be great!

The relevant equation I did manage to get. but I do not know how to solve the problem when the size of A is not equal to the size of B.