E.17.AUD.OOTD:4.2.a - Choose the least-cost honest unit architecture
“One primary subject” is a local default for a short unit meant to carry one readily recognizable move. It is not an ontological law and does not forbid a deliberately structured document that readers need as one unit.
Compare four repairs before splitting by reflex:
| Repair | Retain it when | Reject it when |
|---|---|---|
| Retain one unit with one declared primary subject | one reader goal, one bounded downstream use, and one honest umbrella subject organize all included material; subordinate paragraphs do not introduce an independent move | the umbrella is merely a vague label hiding unrelated subjects or uses |
| Declare an explicit transition inside one short unit | the same reader and bounded use need a small ordered shift, and naming the from/to subject, concern, or move costs less than a split | later readers are likely to extract either part independently, or the second part licenses a different use |
| Retain one explicitly sectioned multi-subject unit | the sections have clear local headings and moves, their dependency or shared decision question makes joint reading useful, and one scope/non-scope declaration prevents overread | section boundaries still leave audience, claim, or permitted-use changes hidden |
| Split into separate units | subjects serve different readers or actions, need independent reuse or approval, or one part falls outside the declared scope of the other | the split creates navigation, duplication, synchronization, or decision-assembly cost without reducing ambiguity |
Choose the least-cost option that preserves comprehension, exact claim meaning, intended use, and protection against overread. Do not optimize the count of subjects, sections, or documents. If a multi-subject container has no truthful umbrella subject and no joint reader use, treat it as a collection of units or split it; do not invent a broad subject merely to satisfy this pattern.