Hi I need help with a question.
If |A| = m ≥ 2 and |B| = 2, how many surjections are there from A to B?
My thinking process: if A and B are both sets, A contains m (which is greater than or equal to 2) elements and B contains 2 elements.
So let A = {a1,a2,...m}
Let b = {b1,b2}
So if you're mapping A onto B and it needs to be surjective, every element of B is assigned to some element of A.
Now I don't know where to go from here? To be a surjection b1 and b2 need something form A mapping onto them, right?