Would you mind explaining the term “subalterns”? Thank you.
“Subalterns” is another name for the relationship between two categorical statements of the same subject and predicate, with the same quality (affirmative or negative) but different quantity (one universal, one particular); That is, between A and I statements, or E and O statements.
On the square of opposition in Introductory Logic, subalternation is divided into two relationships: subimplication and superimplication. But those can be thought of as two aspects of the single relationship of subalternation, and are often presented as such in other logic texts.