Recent content by TheFacemore

From those 2 replies i feel as if I am trying to overthink this problem. Is it that u does not need to be an element of U but it has to be an element of A? or something to that extent?

Homework Statement Let A be a set. Show that there is no surjective function phi: A --> P(A), where P(A) is the power set of A. What does this say about the cardinalities of A and P(A)? Homework Equations Assume that phi is a surjection of A onto P(A) and consider the set U= {a in A : a...