Realm
System Graph
Placement, ownership, boundaries, relations, projections, policies, invariants, and graph shape.
Entries
Boundaries
Boundaries define the scope and context in which observation, interpretation, authority, failure, persistence, delivery, and coordination apply.
Bounded Context
A bounded context is a system-graph boundary within which a particular domain model is defined and applicable and its ubiquitous language has consistent meaning and ownership.
Business Transactions
Business Transactions describe domain-level units of work whose progress, acceptance, rejection, compensation, or completion matters to the business.
Control Models
Control models place adaptive observation, decision, and actuation loops in the system graph.
Effect Models
Effect models describe how semantic effects are placed, related, scoped, and carried through the system graph.
Endpoints
An interaction endpoint is a boundary-relative attachment locus at which a participant, through a port or adapter, sends to or receives from one or more channel directions under an interface and protocol binding.
Entity Models
Entity models describe how the semantic entity role is arranged in the system graph.
Flow Operators
Flow operators are compositional structures that transform, select, divide, combine, order, or distribute values moving through flow views.
Flow Views
Flow views describe movement through the system graph over time.
Fork and Join
Fork and join are paired process-graph structures that expand one continuation into several branch activations and later synchronize selected branch completions into a continuation.
Infrastructure Graph
An infrastructure graph is the system graph projection that relates modeled system structure and guarantee demands to public realization substrate concepts and capability evidence.
Interaction Bindings
An interaction binding relates the semantic and structural parts of an interaction at one exact boundary without making them identical. It states how interface contract roles and protocol roles attach through endpoints to exact channel directions, and which realization is authorized to carry them.
Interaction Channels
An interaction channel is a provider-neutral logical exchange through which values, messages, observations, signals, requests, replies, events, or framed data can move among endpoints. It gives the exchange a stable structural locus, identifies its logical directions, and provides scopes to which required observable properties can be attached.
Interaction Modes
Interaction modes are boundary-relative profiles of how participants are structurally arranged to affect, observe, request, answer, share state with, wait for, or synchronize with one another.
Interaction Protocols
An interaction protocol describes the allowed temporal structure of interactions through an interface. It constrains not only the values that may be exchanged, but also which roles may initiate, which occurrences may follow, how concurrent attempts relate, and how a conversation completes, fails, is cancelled, or remains live.
Interfaces
An interface is a reusable intentional interaction type projected on a surface. It declares roles and meanings that can be instantiated at system boundaries without identifying the reusable type with any one participant, address, endpoint, or realization.
Invariant Scopes
Invariant scopes describe where semantic invariants are attached in the system graph.
Messages and Envelopes
Messages and envelopes describe the finite carriers used to move values and interaction metadata across system-graph boundaries.
Microservice
A microservice is a logical service node in a service model with an explicit profile for independent semantic evolution, contract evolution, ownership, deployment, scaling, failure, recovery, and operation. The profile states which of those boundaries align and where independence remains partial rather than treating *micro* as a code-size or process-count rule.
Multiplexing and Demultiplexing
Multiplexing combines several distinguishable logical interaction flows onto a shared interaction channel or node. Demultiplexing uses an address, key, type, correlation identifier, or other discriminator to recover the intended logical flow or destination.
Observer Models
Observer models describe how semantic observers are placed in the system graph.
Partition Models
Partition models describe how subjects, histories, relations, observations, or work are assigned to distinct ownership, ordering, storage, and execution scopes in the system graph.
Policy Scopes
Policy scopes describe where semantic policies are attached in the system graph.
Process Graphs
Process graphs describe how semantic processes are arranged across time, observer models, entity models, relation models, boundaries, and external systems.
Projection Models
Projection models describe how derived observations or derived state views are arranged in the system graph.
Relation Models
Relation models describe how semantic relations are represented in the system graph.
Replica Models
Replica models describe how one logical subject, history, service role, or derived view is arranged across multiple replica observers in the system graph.
Routing Models
Routing models describe how an interaction selects destinations, recipients, paths, or next processing loci in the system graph.
Service Models
A service model is a system-graph view that bundles semantic responsibilities into logical services and connects provided and required ports on their surfaces through interaction channels. Reusable interface types, interaction protocols, and operational envelopes qualify how those interactions may proceed. It mediates between the domain's entities, relations, queries, and processes and the concrete repositories, deployments, runtimes, and schedulers that realize them.
Surfaces
A surface is a typed, boundary-relative abstraction of a modeled system's externally relevant semantics. It declares what the system provides, requires, may affect, claims under stated assumptions, and must substantiate with evidence without exposing the system's entire internal graph.
System Composition Algebra
This note is a draft, plain-language overview of how Cohesive describes the composition of systems. It summarizes vocabulary under active development; precise operators, typing judgements, equivalences, and proof rules require further refinement before they should be treated as normative.
System Graph
The system graph is the compositional, boundary-relative graph of a modeled system as a whole, in which semantic subjects and roles become explicit nodes and relations with declared placement, interaction, ownership, scope, and boundaries.
Transition Models
Transition models describe how the semantic transition role is arranged in the system graph.