Sections 16 and 46 of the WHS Act recognise that several people can owe a duty over the same matter at the same time, because they share work activities or share premises such as a shopping centre or a construction site. Each keeps its own responsibility to the extent of its influence and control, and all of them must consult, cooperate and coordinate with one another as far as is reasonably practicable. Where a duty is shared, each party should swap information, establish who is handling which obligation, and work together so that the risks are removed or reduced. A hospital and the laundry contractor working inside it both owe the contractor's staff a duty of care, so both must consult those staff and should coordinate how they do it. In the law firm example, a tenant who knows that neglected heating, ventilation and air conditioning can harbour biological hazards checks the lease, asks the building manager when the system was last serviced, and cooperates with the owner's arrangements for the technician's visit.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.