A.4:1 - Problem frame

Use this when a decision depends on whether an independently identified System’s operation matches a selected design account, and that comparison is still unresolved. The account may state an intended operating condition, required result or predicted behavior. Select the account edition and its operative comparison criterion before diagnosing a discrepancy or choosing a change.

The first useful result is a fit, a stated discrepancy or the exact missing/incomparable basis. An engineer can obtain that answer without starting an adaptation loop or changing the System or its design.

Not this pattern when. Reuse a sufficient direct domain comparison. Use A.1.1 for an unresolved model-applicability question, C.2.1 for episteme identity and edition relations, A.3.4 for an actual change claim, and B.4 when repeated adaptation itself needs coordination. An unchanged theorem being cited is an episteme-use question, not a System design/operation comparison.