- #1

Texans80mvp

- 2

- 0

Let C (n,m) be the number of onto functions from a set of m elements to a set of n elements, where m > n > 1 (All of those are greater than or equal to signs). Find a formula relating C (n,m) to C (m-1,n) and C (m-1,n-1).

The second question deals with relations on a Cartesian product of A. A is a set with 8 elements. I was able to figure out that there are 2^64 relations total and 2^8 are reflexive while 2^36 are symmetric. However how many are both reflexive and symmetric? The question reads:

A is a set with eight elements.

How many relations on A are both reflexive and symmetric?

Any help would be greatly appreciated, even a point in the right direction would help. But like I said I am stuck and have almost no clue on what to do for either problem.