subalternation
On the traditional square, the inference from "all" down to "some."
Subalternation is the traditional square's relation between a universal statement and the particular statement of the same quality below it: from A infer I, from E infer O. It holds only when the subject class has members, so the Boolean reading drops it.
Examples
From "All unicorns are white," subalternation would give "Some unicorns are white," which is false because there are no unicorns.
See also