Many real-world systems can be seen as networks of dynamical nodes. Examples range from power grid networks to synchronously firing neural oscillators in the brain. The dynamics – and therefore the function – of such networks are determined by the individual dynamics of each node as well as the interaction between nodes.
Crucially, in many cases the interactions between two nodes are not static: They may be influenced by the state of other nodes or change over time, e.g., via external forcing, intrinsic adaptation such plastic connections. In this case the network is adaptive or co-evolutionary. That adaptive effects are crucial for the network dynamics has been demonstrated, for example, in ecological networks and networks of neuronal oscillators. Despite this, there are only realtively limited mathematical insights into the dynamics of networks with state-dependent and adaptive interactions: Many commonly used models either assume static connections, or they assume static node dynamics. Even if there is co-evolutionary dynamics on and of the network, direct numerical simulation or formal moment approximations are some of the predominant approaches. Hence, there is still a very serious challenge to understand the mathematical fundamentals of adaptive networks. One key goal of the Focus Group "Network Dynamics" is to push the boundaries on the mathematical understanding on network dynamical systems with state-dependent and adaptive interactions.
Furthermore, robust function of networks may be thought of as an emergent dynamic property of the network resulting from the intrinsic dynamics within nodes, the structure and dynamics of connections between nodes, and the interplay of the network with the external environment. Consequently important transient and excitable behaviour is widespread in such networks, e.g., in biomedical applications. Given perturbations different transient and emergent dynamics arise in networks. The significance of such transient effects has been demonstrated in avalanches of gene activation in gene regulatory pathways to drive cell differentiation, development and cancer as well as cell fate in biofilm formation, just to name a few. However, our mathematical understanding of transient network dynamics is in its infancy in spite of some recents efforts. Accordingly, the Focus Group "Network Dynamics"– consisting of Prof. Dr. Krasimira Tsaneva-Atanasova (Hans Fischer Senior Fellow), Dr. Christian Bick (Hans Fischer Fellow) and Prof. Dr. Christian Kühn (TUM-Professor for Multiscale and Stochastic Dynamics) – aims at developing the mathematical understanding on transient emergent network dynamics.