“…In the Hierarchical Graph representation, the adjective "hierarchical" does not imply a "decomposition of the system into different levels of details", as in other hierarchical models (e.g., Goal Tree Success Tree -Dynamic Master Logic Diagram [Hu and Modarres, 2000] and hierarchical clustering [Gómez et al, 2013]), but it simply means that the graph of interconnected CIs is structured in hierarchical levels. In extreme synthesis, the representation is built as follows: at the bottom of the graph, the inputs (i.e., the arcs through which the product is injected into the networks) are represented; at the top, the goals (i.e., the demand nodes that have to be satisfied) are reported; in the middle, all the other arcs (transmission and/or load arcs) that provide product to the demand nodes are organized in hierarchical levels.…”