Many studies have focused on the role played by geographical location in the emergence and building of localised learning capacities (Maskell and Malmberg, 1999). In this perspective, empirical studies have demonstrated that the innovation dynamics of clusters result from the quality of interactions and coordination inside the cluster as well as interactions with external, often global, networks. In this context, knowledge exchange between firms and institutions are claimed to be the main drivers of spatial agglomeration (Canals et al., 2008). Hence, cluster policies have followed the main idea that geographic proximity facilitates collective innovation in that firms can capture knowledge externalities more easily. This idea is in fact very attractive but contains some limitations (Suire and Vicente, 2007): if some clusters are successful, others seem to decline. Therefore, in order to understand the territorial dynamics of clusters, the analysis of the specific nature of knowledge and information flows within a cluster is crucial. The objective of this paper is to enhance the analysis of the role of cognitive and relational dimensions of interactions in territorial dynamics of innovation. We focus on the key sub-process of innovation: knowledge creation, which is above all a social process based on two key complex social mechanisms: the exchange and the combination of knowledge (Nahapiet and Goshal, 1996). We suggest building a theoretical framework that hinges on these two key mechanisms. In this line, we apply Boisot's I-Space model (Boisot, 1998) for the diffusion and exchange of knowledge and suggest completing the model by introducing the concept of architectural knowledge (Henderson and Clark, 1990) so as to take into consideration the complexity of the combination process. This analysis is conducted through the illustrative analysis of three different case studies. We will draw upon the case of Aerospace Valley Pole of Competitiveness (PoC), the Secured Communicating Solutions PoC, and the Fabelor Competence Cluster. The cases show that the existence of architectural knowledge is pivotal to territorial innovation.
