Core Language Ontology

This page defines the core elements and connections that can be used in the Synx-Assure modelling tool.

1) Claim

Definition: Claim

A proposition the assurance case seeks to support (e.g., that a property/requirement holds).

Link rules & cardinalities

  • Outgoing
    • Claim —(is_supported_by)→ Argument (exactly 1)
      (Suppressed if the Claim is marked self‑evident; see §12.)
    • Claim —(has_context)→ Context (0..N)
    • Claim —(has_risk)→ Risk (0..N)
  • Incoming
    • Argument —(introduces_subclaim)→ Claim (0..N) (i.e., this Claim may be a sub‑claim of a parent Argument).

Special constraints

  • Immediate support is 1:1: Each non‑self‑evident Claim must have exactly one supporting Argument; each Argument supports exactly one parent Claim (see §2).
  • Self‑evident Claims terminate the branch and have no Argument (see §12).

2) Argument

Definition: Argument

The reasoning step that warrants a (parent) Claim by invoking sub‑claims and/or evidence.

Link rules & cardinalities

  • Outgoing
    • Argument —(introduces_subclaim)→ Claim (0..N) (hierarchical decomposition).
    • Argument —(is_supported_by)→ Evidence (0..N)
    • Argument —(has_assumption)→ Assumption (0..N)
    • Argument —(has_justification)→ Justification (exactly 1)
    • Argument —(has_risk)→ Risk (0..N)
  • Incoming
    • Claim —(is_supported_by)→ Argument (exactly 1) (the parent Claim)

Special constraints

  • Immediate support is 1:1: An Argument supports exactly one parent Claim.
  • Sufficiency of support (how much evidence/sub‑claiming is “enough”) is a modelling decision expressed in the Justification.

3) Evidence

Definition: Evidence

Concrete artefacts that substantiate Arguments and/or Mitigations (e.g., test reports, analyses).

Link rules & cardinalities

  • Incoming
    • Argument —(is_supported_by)→ Evidence (0..N)
    • Mitigation —(is_evidenced_by)→ Evidence (0..N)
  • Outgoing
    • (None; Evidence does not point to Claims, Risks, or Contexts directly.)

Notes

  • Evidence may be reused across multiple Arguments and Mitigations (many‑to‑many is permitted).

4) Context

Definition: Context

Scope/boundary information that clarifies a Claim (conditions, definitions, variants, e.g., multiple ODDs).

Link rules & cardinalities

  • Incoming
    • Claim —(has_context)→ Context (0..N)
  • Outgoing
    • (None; Context does not link further.)

Special constraints

  • Attachment restriction: Context attaches only to Claims.
  • Multiple Contexts can attach to a single Claim (variants allowed).

5) Justification

Definition: Justification

The rationale for an Argument’s structure — why its decomposition and selected evidence are appropriate.

Link rules & cardinalities

  • Incoming
    • Argument —(has_justification)→ Justification (exactly 1)
  • Outgoing
    • (None; Justification does not link further.)

Special constraints

  • Attachment restriction: Justification attaches only to Arguments; exactly one per Argument.

6) Assumption

Definition: Assumption

A constraint accepted without proof within an Argument’s reasoning (e.g., simplifying parameter, validity bound).

Link rules & cardinalities

  • Incoming
    • Argument —(has_assumption)→ Assumption (0..N)
  • Outgoing
    • (None; Assumptions do not carry Evidence directly.)

Special constraints

  • Attachment restriction: Assumptions attach only to Arguments.
  • Assumptions are justified within the Argument/Justification narrative, not by Evidence links.

7) Risk

Definition: Risk

A threat to the credibility or validity of a Claim or Argument.

Link rules & cardinalities

  • Incoming (exclusive)
    • Claim —(has_risk)→ Risk (0..N) or Argument —(has_risk)→ Risk (0..N)
      (Each Risk attaches to exactly one parent, either a Claim or an Argument.)
  • Outgoing (owned components)
    • Risk —(has_origin)→ Origin (exactly 1)
    • Risk —(has_hazard)→ Hazard (exactly 1)
    • Risk —(has_impact)→ Impact (exactly 1)
    • Risk —(has_mitigation)→ Mitigation (0..N)

Special constraints

  • Risks do not attach to Evidence.
  • A node (Claim or Argument) may have multiple Risks.
  • Risks are separate nodes that must have an Origin, Hazard, Impact, and Mitigation(s). ***

8) Origin

Definition: Origin

The source or causal locus of a Risk (e.g., data, model, operation).

Link rules & cardinalities

  • Incoming
    • Risk —(has_origin)→ Origin (exactly 1)
  • Outgoing
    • (None.)

Special constraints

  • Attachment restriction: Origin exists only as a child of a Risk.

9) Hazard

Definition: Hazard

The hazardous condition/event within a Risk.

Link rules & cardinalities

  • Incoming
    • Risk —(has_hazard)→ Hazard (exactly 1)
  • Outgoing
    • (None.)

Special constraints

  • Attachment restriction: Hazard exists only as a child of a Risk.

10) Impact

Definition: Impact

The consequence if the Hazard manifests.

Link rules & cardinalities

  • Incoming
    • Risk —(has_impact)→ Impact (exactly 1)
  • Outgoing
    • (None.)

Special constraints

  • Attachment restriction: Impact exists only as a child of a Risk.

11) Mitigation

Definition: Mitigation

A treatment/control intended to reduce a Risk.

Link rules & cardinalities

  • Incoming
    • Risk —(has_mitigation)→ Mitigation (0..N)
  • Outgoing
    • Mitigation —(is_evidenced_by)→ Evidence (0..N) (recommended but not mandatory)

Special constraints

  • Evidence for a Mitigation is optional in the ontology.

12) Self‑evident flag (Claim modifier)

Definition: Self-evident Flag

Marks a Claim as self‑evident/true for the purposes of the case.

Effect on links

  • Forbidden: Claim —(is_supported_by)→ Argument
  • Allowed: Claim —(has_context)→ Context (0..N)
  • Allowed: Claim —(has_risk)→ Risk (0..N)