PHY.3:4.2 - Establish which physical restrictions cover the candidate mechanisms

Select the physical account that connects the requested change with a conserved quantity, an ordered change, a preserved relation or another necessary condition. State its regime and the systems to which it applies. A local balance law can require a larger boundary when something crosses it; a law for a closed process can require explicit surroundings when the proposed device exchanges matter or information.

Explain why every device in the proposed conclusion admits the chosen description. MMP.10:4.4 supplies this coverage requirement. Physically, it can mean including a reservoir and its controller, representing an unobserved auxiliary, or admitting all interactions allowed by the theory instead of only one circuit. Restrict the conclusion to the designs described if this coverage remains incomplete.

An enlargement of the allowed class can make exclusion easier: if even a class with additional resources cannot realize the requested transformation, its contained class cannot do so. Show that containment. An approximation chosen because it is easy to calculate does not automatically give such an enlargement; it can remove a coupling or noise source that changes what is possible. When only an approximate account is justified, propagate a suitable error allowance or retain a conditional result at that model’s stated scope.

Use B.5.TU to recover the physical theory’s premise and its consequence for the case. The output of this step is the applicable restriction and the reason it covers the proposed physical class. Further measurement is useful only if its possible result changes that premise or the next choice; C.11.DUA helps resolve a consequential uncertainty about that effort.