3.6.2 Logic 101

Set up

Perform the weekly set up instructions for project 3, homework b.

What to hand in

A file answers.txt with answers to the following questions.

1. Why does prove-simple use mapcan as the list mapping operator? Hint: "nil".
2. The following functions all return lists of multiple bindings: prove-simple, prove-and, prove-or, prove-not. Why don’t we just return one binding?
3. Given an example of "r" before and after it is processed by change-vars.
4. The function prove-code evals a structure called code that creates a let statement which defines some vars (local variables) then calls some code expr. What is going on here?

A revised form of 15.lisp with:

• Code for test ">" into the prove function. With that extension, you can have sub-goals in clauses that look like this: "(> ?age1 ?age2)". Hints:
  • use prove-code.
  • Add more entries to the top of the "case" statement in prove. Remember to return (list binds).
  • If ">" is not true, just return nil.
• A deftext function that uses with-answer to find the oldest person amongst a group of people. Use the following logic:
  • The oldest person is the person for which not other person has an older age.

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