Figure 1
From: The central role of peripheral nodes in directed network dynamics
Bow-tie architecture of a directed network, composed of a core and its periphery. The CORE is the largest strongly connected component (largest set of nodes reachable from each other through a sequence of directed links). The periphery comprises the IN and OUT components – the sets of nodes in sequences of directed links leading into and out of the CORE respectively1,2,3,43 – and a hierarchy of tendrils (such as those connecting into and out of the OUT and IN components, respectively) and tubes (directly connecting the IN and OUT components)36. As indicated by the arrowheads, the overall connectivity of this architecture is feedforward, from SOURCE nodes (IN nodes without in-links) to SINK nodes (OUT nodes without out-links).
