ction of <span
 style="font-style: italic;">instances
generate</span> a concept whose intent is the collection of all types
that
classify those instances. Any collection of <span
 style="font-style: italic;">types generate</span> a concept
whose extent is the collection of all instances that are classified by
those types. For any collection of concepts there is a <span
 style="font-style: italic;">join </span>concept
defined as the concept generated by the intersection of the intents.
For any collection of 