Ordering, Effects, Concurrency, and Cycles
SUMMARY
Specifies the semantics required when several valid traversals can produce different material outcomes.
DETAIL
Schema validity alone does not determine execution order. Two paths may both be structurally admissible while producing different outcomes because they read mutable state, write overlapping regions, invoke external systems, consume scarce resources, or depend on time.
Pure morphisms can be reordered, cached, fused, or speculatively evaluated when their contracts guarantee referential transparency. Stateful morphisms require declared read and write regions, version expectations, or transactional boundaries. External effects require semantics for idempotency, retries, timeouts, compensation, cancellation, and authority. Concurrent branches require conflict detection and an explicit join rule.
SCSEG should distinguish three forms of determinism. Structural determinism means the same graph state yields the same candidate paths. Plan determinism means the same path-selection and scheduling rules yield the same execution plan. Result determinism means different permitted schedules still produce equivalent outputs. A system may provide one guarantee without the others.
Cycles cannot remain semantically ambiguous. A cycle may mean fixed-point computation, bounded iteration, feedback control, stream processing, recurrence over time, or an invalid dependency loop. The cycle contract must declare its interpretation, termination or convergence condition, state carried between iterations, and behavior when convergence fails.
An immutable or append-only graph can reduce write conflicts by representing each state transition as a new node rather than mutating shared state. It does not remove all concurrency problems: external capabilities, resource reservations, and conflicting interpretations may still require coordination.
Traversal discovers what is structurally reachable. An effect-aware planner decides what may execute, in which order, with which isolation, and how partial failure is contained.
WHY THIS EXISTS
Supports runtime feasibility analysis, scheduling, concurrency control, fixed-point reasoning, and separation of graph validity from material execution correctness.
SOURCE CONTEXT POINTERS
- /concepts/schema-contracted-synthetic-execution-graph/DEEP.txt
- /concepts/schema-contracted-synthetic-execution-graph/PATTERNS.txt
- /concepts/schema-contracted-synthetic-execution-graph/RISKS_AND_CONTRADICTIONS.txt
EVIDENCE QUESTIONS
- No evidence query recorded