PHY.Preface:3 - Solution - Connect physical methods through their results

PHY.Preface:3.1 - Construct and constrain the account

PHY.4 begins while the response law is still unknown. Recover the participants, transform the relevant situation, and derive the restrictions supplied by symmetry, dimensions, balances and dissipation where their physical grounds hold. The remaining unknown function or state directs further work.

PHY.5 chooses the physical detail needed at the requested scale and duration. An omitted state can leave memory or fluctuations; a fast response can matter during a transient. Its result tells mathematical reduction what must be retained or bounded.

PHY.6 combines physical participants, exchanges, response laws and compatible preparation into an evolution. A balance alone can leave a response undetermined. Locating that missing contribution is useful before any solver is selected.

PHY.7 offers another construction when a physically justified variational principle applies. The interactions, allowed comparisons and boundary freedoms determine what is varied. Mathematical variation then derives a consequence. A direct balance remains sufficient in many cases; applying an action formalism to every problem adds work without a corresponding gain.

PHY.8 constructs collective predictions from physically admissible alternatives and their weighting grounds. It retains correlations, preparation and the difference between sampling a distribution and following physical evolution. A distribution or sufficient bound can remain useful when a particular moment or equilibrium approximation is unavailable.

PHY.Preface:3.2 - Compare, observe and construct another use

PHY.1 determines which effects and scale relations let a physical result travel to changed conditions. PHY.5 deepens the question when a neglected effect changes that transfer.

PHY.2 constructs an arrangement whose interactions supply a wanted physical consequence. The construction must include preparation and interpretation. Similar-looking equations can suggest an analogue while leaving those physical tasks unresolved.

PHY.9 makes the wanted difference affect an indication. It develops the coupling, reference or preparation, including disturbance and ambiguity. The result supplies the observation relation used in subsequent inference or comparison.

PHY.10 constructs a physical contrast between accounts that agree under earlier conditions. It follows the changed preparation through the response and readout, retaining parameter freedom and alternative apparatus explanations. A failed comparison returns to the particular premise that can change it.

PHY.3 derives a bound or impossibility from the complete transformation and an admissible comparison. That result may finish the question or show which physical premise a different construction would have to change.

These connections form possible routes. They do not prescribe a ten-stage workflow. A known response can enter at measurement; an unknown interaction can enter at law construction; a useful impossibility can end work before a device or computation is built.

PHY.Preface:3.3 - Constituent actions in ongoing work

Acquiring a reading can be part of testing a physical account while the discriminating investigation is already under way. If rival accounts agree at equilibrium but differ during a transition, a settled-value observation cannot answer the same question: its timing must change. Instrument use, the mathematical consequence and knowledge of the accounts can be available separately while the coordination of intervention and observation is missing. The domain’s observation Method supplies that intermediate contribution and its equipment conditions.

FPF B.1.5.EW helps recover these constituent–whole connections; B.1.5.RS examines a proposed replacement. Use the parts of the vertical that can change the present result. A Method described here can require additional capability, available support and compatible resources at other grains.