Problem 1: Consider the following languages L1 = {0, 1}, L2 = {01, 12, 20}, and L3 = {02, 21}.
2. List all strings of length 4 of L*, where L = {a2mbn, n, m >= 0} (if you think there are no such strings then explain why).
3. List all the elements of L1+ − L13 ∙ L1+.