Processes

Figure 4.2: Hierarchy of Processes in KR Ontology

Processes are occurrents, physical entities and they are independent of any other entity. They can be described by two points in time, the starting and end point of the process, and the changes that occur in this time interval. Figure 4.2 shows a further distinction of processes. In a continuous process changes take place continuously. An example is again an electron moving through space. In a discrete process changes occur only after some time. The time interval between two changes is called a state. The change is called an event.

Continuous process are distinguished in three different kinds, Initiations, Continuations and Cessations. In the first kind, an explicit starting point can be given. An example is a marathon. In the latter an ending point can be explicitly stated. An example might be an execution. In Continuations neither a starting nor an end point is relevant. An example is an electron moving through space.

A Nexus is a physical entity, mediating some other entities. It consist of a bundle of prehensions, like the participants of a process.

In the KR Ontology, a Situation is a Nexus considered as an occurrents. It mediates the participants of a process. It is therefore similar to a Structure, which is a Nexus considered as an endurant. A Structure mediates multiple objects, whose joint constitutes the Structure. To imagine a Situation better, consider a marathon. A marathon is a process, and there are some kind of participants, a route, a landscape, weather. Then a situation is some kind of entity that holds all those things together, the time, the space, the process and all entities involved.

This view on situations does not lead to a theory of situations as in barsit, and we will take another position later in this thesis.