Six Birds Foundations VII: Lawful Theory Interaction

Six Birds Foundations VII: Lawful Theory Interaction asks when interaction across the boundaries of two theory packages is admissible. It closes a catalog of 36 entries covering access and admission, contact and join, enablement and descent, and dynamics and residue, while separating contact from join, strictness from directionality, enablement from descent, and source independence from behavioral non-factorization. The paper gives eleven scoped obstructions with named escape routes, two refuted proposed laws with surviving conditional content, and two formally closed deferrals. Its central object is a join of theories relative to a declared admissibility regime; the construction is neither assumed to exist nor treated as free.