https://gall.dcinside.com/mgallery/board/view/?id=math&no=8880&page=1


1. Java(doug) - 가정

2. InThisClass(doug) - 가정

3. ∀one (Java(one) → PayHigh(one)) - 가정

4. Java(doug) → PayHigh(doug) - ∀소거

5. PayHigh(doug) - →소거

6. InThisClass(doug) ∧ PayHigh(doug) - ∧도입

7. ∃one (InThisClass(one) ∧ PayHigh(one)) - ∃도입


1. ∀one (InJersey(one) → Ocean(one)) - 가정

2. ∃one (InJersey(one) ∧ NeverSeen(one)) - 가정

__ 3. InJersey(one) ∧ NeverSeen(one) - 가정

__ 4. InJersey(one) - ∧소거

__ 5. NeverSeen(one) - ∧소거

__ 6. InJersey(one) → Ocean(one) - ∀소거

__ 7. Ocean(one) - →소거

__ 8. Ocean(one) ∧ NeverSeen(one) - ∧도입

__ 9. ∃one (Ocean(one) ∧ NeverSeen(one)) - ∃도입

10. ∃one (Ocean(one) ∧ NeverSeen(one)) - ∃소거