Question:Using the inclusion-exclusion method, what is the number of
functions f from the set {1,2,...,n} to...
Question
Using the inclusion-exclusion method, what is the number of
functions f from the set {1,2,...,n} to...
Using the inclusion-exclusion method, what is the number of
functions f from the set {1,2,...,n} to the set
{1,2,...,n} so that f(x)=x for some x
and f is not one-to-one?