RHODES is an environment for modelling software processes, in which software processes are described by using a Process Modelling Language called PBOOL+. In this environment, a software process is built from PBOOL+ process components that can be reused to construct other processes. To identify well-formed process components, we study properties to be able to characterize topological structure of the components. These properties should relate intrinsically to cohesion of a component, and coupling between components. We will consider two classical properties that originated from graph theory, which are connection and transitive closure. These two properties are sometimes too strict to be applied, so we propose several weaker properties that are still useful for characterizing good components. The article aims to present these topological properties and their applications to reusable process components in context of the RHODES environment.