This is the first Homework. It will be graded and a grade will be assigned. This homework should not take more than a couple of hours.

In this homework you will construct a few Natural deduction style proofs using the code discussed in lecture. You will need the following 3 files.

1. NatDed.hs
2. Blocks.hs
3. SimpleProp.hs

• p /\ q |- q /\ p

• (p /\ q /\ r), (s /\ t) |- q /\ s

• p -> (q -> r), p -> q |- p -> r

• p1 -> p2, ~p2 |- ~p1

  This rule schema is called modus Tollens

• p1 \/ ~p1

  This is often called the rule if the excluded middle

Put all these functions into a file called Hw1.hs, check your proofs and submit it to D2L.