Question

In: Advanced Math

Let f(n,k) be the number of equivalence relations with k classes on set with n elements....

Let f(n,k) be the number of equivalence relations with k classes on set with n elements.

a) What is f(2,4)?

b) what is f(4,2)?

c) Give a combinational proof that f(n,k) = f(n-1,k-1)+k * f(n-1,k)

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