A.6.RCD:5.3 - Supply-chain reachability: subject-bounded query or reusable predicate definition

Situation. One planner asks whether Supplier_A can reach Plant_B inside SupplyNetwork_North_2026. Other planners want the same directed-reachability rule for independently identified supply-network structures.

Base and derivation. Name the direct edge-relation kinds, direction, structure parameter, source and target parameters, path or closure rule, zero-length and cycle policies, applicability, and edge-definition editions. A one-off answer is a local compound claim. Repeated queries only about SupplyNetwork_North_2026 may use a subject-bounded compound-law episteme whose EntityOfConcern is that exact structure and whose reuse boundary excludes other structures. When the same parameterized rule is reused across independently identified structures, publish DirectedReachabilityPredicate_v1 as a predicate-definition episteme whose EntityOfConcern is that exact reusable definition. If its claim graph supplies A.6.0’s subject and value range, Vocabulary, Laws, and Applicability, it may independently satisfy ordinary U.Signature membership without becoming a RelationSignature.

Positive case. A path exists whose every edge is an obtaining occurrence of the admitted base relation under the selected structure and closure rule.

Discriminating failure. A graph representation contains a visual or stored path, but one edge points in the wrong direction, denotes a different base relation, or belongs to a superseded structure edition. Representation connectivity therefore does not satisfy the reachability predicate.

Disposition and stop. The one-off query stops at disposition 2. Repeated use confined to one exact structure stops at disposition 3’s subject-bounded branch. Cross-structure reuse stops at disposition 3’s reusable predicate-definition branch and may add ordinary A.6.0 U.Signature membership. If a subject practice later needs reachability occurrences with action-facing identity, recurrence, continuation, or participation in another relation, the A.6.RCD application records a derived reachability-kind candidate plus a proposed direct subject settlement; apply the E.24 and E.24.UK admission tests and the A.11 parsimony test when current. Create a RelationSignature only for an admitted relation kind. Path identity, query-result-row identity, predicate-definition identity, subject-structure identity, and relation-occurrence identity are not interchangeable.