C.29.BB:10 - Architectural Rationale

The independent difficulty is constructing what is added and what cancels. Once compatible local equations are supplied, summing them is elementary; selecting parts, quantities and shared exchanges is the substantive work that makes the sum useful.

A.3.3.TR constructs state-change rules and already demonstrates cancellation of internal forces. This pattern develops the choice and revision of a balance boundary across different quantities and descriptions. C.29.1 handles result transfer between mathematical accounts; the present construction explains why one particular aggregation preserves a total and what must be restored for a smaller-boundary question.

The finite-interval relation is the first construction because it works for discrete events as well as physical storage. Differential and field forms require the subject’s regularity and transport assumptions. This separation keeps an elementary count accessible while leaving richer physical and numerical constructions available.