>>38
You're logic breaks down the the case where S=E (ie. functions from the empty set to the empty set).
In this case the set ExS=E. There is one subset then of ExS, which is E. So let's set K=E and see if it is a map from E to S.
the condition you give is that "if (a,b) appears in K, then no other element of K is (a,c) for any c not equal to b" or in other words that "it is NOT TRUE that (there is some (a,b) and (a,c) both in K where b is not equal to c)".
Well, as K is empty, the bracketed statement is false, and so the entire statement is true; hence, by your own definition (which is indeed correct), the empty set IS a function from E to E.
Which is what I said in the first place.
Actually generally, by your definition again, there is ALWAYS exactly one function from the empty set to another set (the empty function). QED.