**Due Sep 3**

- Exercise 2.6 (1). In addition to showing introduction and elimination rules and verifying local soundness and completeness, also assign proof terms and extend the ML implementations of proof terms to include a primitive equivalence.
- Exercise 2.8. Write down the proof terms in ordinary mathematical notation and then translate them to ML in a form appropriate for the bi-directional proof checker discussed in class. You do not need to show the natural deduction itself, only the proof terms.

Frank Pfenning fp@cs