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wendawu158fifthist
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Fixed solution to 1.11
Surely if two sets are finite and have the same number of elements, there exists an injection between them?
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src/chapters/1/sections/counting/problems/11.tex

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\item Each of the $n$ inputs has $m$ choices for an output, resulting in
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$$m^{n}$$ possible functions.
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\item If $n \geq m$, at least two inputs will be mapped to the same output,
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\item If $n > m$, at least two inputs will be mapped to the same output,
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so no one-to-one function is possible.
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If $n < m$, the first input has $m$ choices, the second input has $m - 1$
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If $n \leq m$, the first input has $m$ choices, the second input has $m - 1$
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choices, and so on. The total number of one-to-one functions then is
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$$m(m-1)(m-2)\dots(m-n+1) = \frac{m!}{(m-n)!} $$
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\end{enumerate}
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\end{enumerate}

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