Knowledge representation research is not only formal, it is also
descriptiveand normative. Its aim is to implement a formal system which
captures a practically relevant body of cognitive faculties employed by
humans and capitalizes on its technical strength to extend human
knowledge representation and reasoning capabilities. In this monograph,
the author develops formalisms for his own notion of a vivid knowledge
representation and reasoning system, characterized by the presence of
two kinds of negation (weak and strong) and the requirements of
restricted reflexivity, constructivity, and non-explosiveness. The book
is based on work carried out within an interdisciplinary research
project at the Free University of Berlin.