The aircraft function implementation process spans several system development processes, each of which may contain several item development processes, with integral processes repeated throughout; the work is iterative and concurrent and may be entered at any point. A brand-new aircraft-level function starts from the top-level function definitions; adding a function may instead start from a change to one item, but whatever the starting point, the effect of the new or changed function on the other aircraft-level functions and the requirements behind them is assessed. The output is a list of aircraft functions and their requirements.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.