2. (20 points, 10 points each) a. Write a recursive definition for the set of bit strings that have m ones followed by n zeros for all positive integers m and n. Here are some of the strings in the set: 1111100, 10, 100, 11110. Here are some strings not in the set: 111001, 11, 0, 0111. b. Give a recursive definition of the function min so that min(a1, a2, ....an) is the minimum of the n numbers a1. a..... an