1.

2.

3.

4.

5.

6.

2) Consider the wff .

Find the flaw in the following "proof" of this wff.

1. hyp.

2. 1, ei

3. 2, eg

3) Prove that is a valid wff.

4) Consider the wff:

a) Rewrite the wff after applying the deduction method.

b) Prove that the wff is valid.

5) Every member of the board comes from industry or goverment. Everyone from goverment who has a law degree is in favor of the motion. John is not from industry, but he does have a law degree. Therefore, if John is a member of the board, he is in favor of the motion.

Using predicate logic, prove that the argument above is valid. Use the predicate symbols: