Observer-Local Branches as Causal Accessibility Sectors in DAGI

The Directed Acyclic Graph Interpretation (DAGI) represents physical processes as a single locally finite directed acyclic graph of informational states, records, and admissible updates. This note refines the meaning of ``branch'' inside that ontology. A branch is not an ontologically duplicated universe, an arbitrary subset of nodes, or a complete microscopic path. It is an observer-local causal accessibility sector: the strict quotient of a record-conditioned causal cone by exact indistinguishability over the accessible record algebra of a specified observer or observable class. The local temporal asymmetry of a node is expressed without adding a stochastic primitive to the ontology: the resolved past is the set of persistent accessible records, while the unresolved future is the set of admissible record-candidates that may become persistent records along directed continuations. Interference is described as amplitude-level evaluation over histories that share the same persistent-record trace, where concurrent accessible records are retained as a partial order rather than forced into a linear word. A distinguishing record refines a coherent macro-node into subnodes; erasure coarsens the accessible record trace and can restore conditional interference classes. In strict graph language, nodes are coarse-grained informational states or events, edges are admissible update relations that change downstream reachability or distinguishability, and records are topologically persistent updates whose distinguishing descendants remain accessible beyond the local decorrelation scale. Charge, field, observer, branch, and connection are not additional ontological entities above the graph, but coarse-grained descriptions of stable subgraph structure and reusable edge-update rules. Causal-cone posets provide a natural computational representation of such accessibility sectors, while powerset decompositions remain useful but physically less structured baselines. The resulting branch ontology is concise: the global DAG contains the admissible informational structure; a local observer occupies a record-conditioned accessibility sector; persistent records refine that sector; admissible record-candidates define possible future refinements; erasure coarsens it; macro-nodes quotient inaccessible micro-variation; and physically meaningful posets are those that track causal accessibility rather than arbitrary set membership.