Type-Theory

Type theory, in one sense, is the view that some category of abstract entities—sets, in the simplest example, but there are analogous views of properties, relations, concepts, and functions—come in a hierarchy of levels, with an entity of one level applying to (having as members, or having as instances, or ...) entities only of a lower level.

 

 

 

 

cutiesome.blogspot.com/2012/06/type-theory.html

Done