Implication

IMP (p v q) :: (~p > q)

You meant to write

Implication

IMP (p > q) :: (~p v q)

No non-P is non-S. ]]>

All S are P. True

No non-S are non-P. Undetermined

Because I know when you think of it, you can not determine the validity of the second proposition but then I would like to understand the steps using the traditional square of opposition and immediate inferences.

Thanks.

]]>4. ~F AIP

5. ~(D . E) 2,4 MT

6. ~D v ~E 5 DEM

7. E 1,3 MP

8. ~~E 7 DN

9. ~D 6,8 DS

10. D 3 SIMP

11. D . ~D 9,10 CONJ

12. ~~F 4-11 IP

13. F 12 DN

14. (C . D) > F 3-13 CP ]]>