A.6:10 - Rationale

The claims in a boundary description concern:

• a mathematical object (signature: operations over vocabulary, governed by laws),
• an engineering boundary signature (stable intent, evolvable implementations),
• a governance object (commitments, responsibilities, deontics), and
• actual occurrences and evidence (effects may arise through Work, natural or spontaneous transformation, formal change, or another directly governed interaction, and evidence supports but does not create them).

Mixing these claims makes it harder to distinguish a semantic boundary change from an implementation change, and to test each claim against its own rule and evidence.

The stack creates a default direction of dependence: higher layers constrain lower layers, not vice versa. The matrix creates a default classification that is not reliant on word choice alone and therefore survives natural‑language variation (“must”, “guarantee”, “valid”, “allowed”).