PSD.4:0.1 - Working Distinctions

Working term	Meaning in this pattern
engagement boundary	The `PSD.1` boundary around the decision-support return, recipient, subject, horizon, receiving use, and authority.
problem boundary	The provisional cut that determines which formulations, bearers, concerns, relations, conditions, horizons, evidence, and intervention families are treated as material now.
material exclusion	An omitted or deferred item that could change the current result and therefore must remain visible with a reason, uncertainty, and reopen condition.
usable scope	The smallest current problem boundary adequate for a named next result and its assurance burden. It need not be exhaustive or permanent.
reopen basis	An observable change or newly recoverable value that can make the current boundary too narrow, too broad, or otherwise unfit for the receiving use.
`U.Scope`	A declared scope for exact `U.ContextSlice` membership, governed by `A.2.6`. An ordinary problem boundary need not be reified as one.