In the traditional square of opposition, how many kinds of relationships are there among the propositions?

Question

Quizplus · Accepted Answer

There are four kinds of relationships among the propositions in the traditional square of opposition:

1) Contradiction (A and O, E and I are contradictories because they differ in quantity and quality) 
2) Contrariety (A and E are contraries because they are both universal but differ in quality) 
3) Subcontrariety (I and O are subcontraries because they are both particular but differ in quality) 
4) Subimplication (A and I, E and O have a subimplication relationship because if the universal statement is true, the corresponding particular statement must also be true).

In the Traditional Square of Opposition, How Many Kinds of Relationships