Description of problem solving using Petri Nets

This paper explores the possibility of using Petri nets as a formal language for pupils to represent their own personal knowledge. The underlying hypothesis is that the process of identifying and defining the knowledge structure of a given content area, makes it easier for the pupils to use the knowledge itself (solving a problem, expounding an argument, etc. ...). The remarks refer to experiments carried out with pupils in the first years of higher secondary school (14-15 years old) and deal with the graphical representation of problem-solving procedures for some simple mathematical problems, with the aim of establishing the most suitable problem-solving procedure. In describing the experiments it will be shown how this type of activity can on the one hand foster self-checking and the consolidation of learning, and on the other hand accustom the pupil to a hierarchical view of a particular knowledge domain, that is, to a distinction between 'preordinate' and 'subordinate' knowledge.