This unsatisfactory situation was the motivation to investigate in our dissertation [1] the notion of occurrences in some detail. Thereby, an occurrence is determined by three aspects: an occurrences is always an occurrence of a syntactic entity (its
shape) in a syntactic entity (its
context) at a specic position. Context and shape are meaningful combinations of the well-known syntactic entities. Our crucial idea is to represent the positions by the so called nominal forms as introduced by Schütte [4]; as a consequence, we obtain a strong and general theory of occurrences.