i am trying to prove this statement, it is obvious, but i just cannot get the clue where and how to start to prove that this statement is true.
the statement is this: $(A \setminus C)\times(B \setminus D)\subset(A \times B)\setminus(C \times D)$
i am starting like this:
$x \in A \wedge x \notin C \times x \in B \wedge x \notin D $ ... but i dont know how to come to the idea that this is a subset of the right side of the first statement. :(
can someone give me a hint please?
thanks a lot