Brereise 3. Foundations Set Theory Lecture notes: ' A litrle of mathematics'. Answer by true or false to these questions and explain: AB=BA AB=BA AUB=BUA Answer the following questions: 4. Let S={ abad } and T={{,a}. 41. Compute ST. 42. How many elements are there in the Powinnst of S ? 43. Compute the Powerset of 5. Explain why the Cartesian product of 2 sets is an inefficient operation to perform. Be very specific and use numbers