A.I.

E.O .-- Combining the two kinds of Quantity, Universal and Particular, with the two kinds of Quality, Affirmative and Negative, we get four simple types of proposition, which it is usual to symbolise by the letters A.I.

E.O., thus: A.

Universal Affirmative -- All S is P.
I.

Particular Affirmative -- Some S is P.
E.