Let $F$ be the number of fixed points of a random permutation on $n$ items. Show that as $n$ approaches infinity, the distribution of $F$ approaches a Poisson distribution with a mean $(\lambda)=1$.
Random Permutation Poisson proof
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probability
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0In fact $F$ and the Poisson distribution have the same moments up to and including the $n$'th. See e.g. http://groups.google.com/group/sci.math/browse_thread/thread/a617036892cf4889/22f6dcf1706a3ebb? – 2012-05-04