We show that the defining structures of algebraic quantum field theory (AQFT) arise naturally within Modal Triplet Theory from admissible chart structure and coherent projection. Local observable algebras are associated with admissible domains, and their overlap relations induce a net (precosheaf) satisfying isotony, locality, and the absence of a global algebra. No background spacetime, causal metric, or global section is assumed. Locality and horizon phenomena are derived as consequences of representability constraints rather than imposed axioms. The construction situates AQFT as a downstream organizational layer within MTT and clarifies its domain of validity.
Peter Nero (2026) studied this question.