Formal Concept AllalY.5is is a field of applied mathematics based on the math ematization of concept and conceptual hierarchy. It thereby activates math ematical thinking for conceptual data analysis and knowledge processing. The underlying notion of "concept" evolved early in the philosophical theory of concepts and still has effects today. For example, it has left its mark in the German standards DIN 2: )30 and DIN 2;3: )1. In mathematics it played a special role during the emergence of mathematical logic in the 19th century. Subsequently, however, it had virtually no impact on mathematical...