Introducing time in reaction systems

Reaction systems are a formal model of interactions between biochemical reactions. The main observation underlying the formulation of this model is that such interactions are based on two basic mechanisms: facilitation and inhibition. This paper continues the investigation of reaction systems, and in particular, it proposes a formal framework for introducing time into reaction systems. Within this framework one can formally define and investigate notions such as reaction times, creation times of compounds, their life spans, etc. (C) 2008 Elsevier B.V. All rights reserved.