1. Read pp. 79-87
2. Email solutions and evidence of testing for:
   1. Suppose we want to use lists to represent sets. Order and repetition are not important in sets, that is, the set {1, 2, 3} is equal to the set {3, 2, 1} is equal to the set {2, 2, 1, 3}. On the other hand, each of the lists '(1, 2, 3) , '(3, 2, 1) , and '(2, 2, 1, 3) are distinct as lists so the built-in equal? predicate will show them unequal. Your task is to define a setequal? predicate that will return #t if two lists (given as arguments) are equal as sets and return false if the two lists are not equal as sets.

      Hint 1: The sets, A and B are equal if A is contained in B and B is contained in A, where set containment is defined: X is contained in Y if every element of X is a member of Y. Earlier, we wrote a predicate memb? that would determine if a single element was a member of a list. It would be worth looking at this definition again. We ought to be able to define a predicate "contains?" that takes two lists as arguments and returns #t if the first argument is contained in the second when they are viewed as sets and returns #f if they are unequal as sets. Think about this.
      Hint2 (for contains?): A predicate that calls itself is reasonable here.
      You need a stopping condition. If A is empty (determined by the built-in predicate null?), then A is certainly contained in B.
      If the first element of A is not in B then A is certainly NOT contained in B.
      If the first element of A is in B, then A is contained in B if the rest of A is contained in B.

   2. page 60, ex1.30
   3. page 61, ex1.32a (use to make sum and product and test your new sum and product on some examples from SICP).

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