A.15.1:9.1 - Temporal aggregation return

For utilization, lead time, cycle time, phase coverage, or another temporal roll-up, use B.1.4. Name the exact work refs, carrier or aggregation concern, time window, coverage and non-overlap conditions, aggregation policy, and admissible use there. Union, convex hull, and optional Gamma_time notation are properties of that recovered temporal aggregation, not fields or identity invariants of a Work occurrence.

When the exact B.1.4 result selects the Work-interval profile, retain these use-specific choices:

• Union of intervals for utilization or availability: preserve every covered instant and do not count overlap twice.
• Convex hull [min t_start, max t_end] for lead time or cycle time: preserve elapsed span from first start to last end, including gaps.
• Declared algebraic behavior: for either exact set-based policy, duplicate input is idempotent, input order is irrelevant, and adding intervals cannot shrink the union or hull. If another policy lacks those properties, name it rather than borrowing the union/hull result.

Never switch union and hull silently between KPIs. The formulas above profile a recovered B.1.4 aggregation over Work intervals; the selected B.1.4 claim, not A.15.1, states the temporal result.