User:Sterling/fcb

Reduction => Simplicity, but enough expressive power to express all information relevant for the view.

E.g. Logical ER-Model (Business view, no implementation), Use-Case-Model (customer view on functionality), State model (only states/behaviour of the system) ...

Hierarchy of expressive power
...
 * 0 Propositional languages
 * 1 (Relational) first order languages
 * 2 Regular languages (Type-3)
 * 5 Recursive enumerable languages (Type-0)

2-5 is defined as the Chomsky Hierarchy. The cohesion from 1 to 2 is given by Fagin's Theorem.

Central Issue: Rightsizing expressive power of Language.

Propositional Language
Hypercube and special case of FO. A(x).

Extension of Propositional Language
Multi Column Relation. Hypercube. Property view. Concept Lattice.

Modal Logics
Kripke Semantics as FO

First Order to Regular Languages
Fagin Theorem