Barbara Gallina Dian Balta Ingmar Kessler Jule Hendricks Tomas Bueno Momčilović OntoGSN is an ontology for managing assurance cases in the Goal Structuring Notation (GSN). The goal of the ontology is to help users in linking the elements of their cases - claims and evidence - with the internationalized resource identifiers (IRIs) of represented concepts, events and data, and in evaluating the validity of their argument. OntoGSN Bueno Momčilović, T. (2026). OntoGSN (Version 1.3.0) [Ontology]. https://doi.org/10.5281/zenodo.17808330 2025-02-20 2026-11-05 2026-11-05 10.5281/zenodo.17808330 gsn https://w3id.org/OntoGSN/ontology# [Disclaimer from the GSN Community Standard v3.0]: While the authors and the publishers have used reasonable endeavours to ensure that the information and guidance given in this work is correct, all parties must rely on their own skill and judgement when making use of this work and obtain professional or specialist advice before taking, or refraining from, any action on the basis of the content of this work. Neither the authors nor the publishers make any representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to such information and guidance for any purpose, and they will not be liable for any loss or damage including without limitation, indirect or consequential loss or damage, or any loss or damage whatsoever (including as a result of negligence) arising out of, or in connection with, the use of this work. The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of their employers, the SCSC1 or other organisations. https://w3id.org/OntoGSN/ 1.3.0 GSN is a graphical argument notation which can be used to document explicitly the elements and structure of an argument and the argument’s relationship to evidence. A definition prefixed [OntoGSN] is this ontology’s wording, not the GSN Community Standard’s. Every definition, tagged or not, has a record in the design record under development/design/ naming the passage it rests on, or stating that it rests on none. Argument A body of information presented with the intention to establish one or more claims through the presentation of related supporting claims, evidence and contextual information. A connected series of claims intended to establish an overall claim. Core GSN Artefact Evidence [OntoGSN] Information or objective artefacts (e.g., files) being offered in support or context of one or more claims. Core GSN Artefact Reference [OntoGSN] An element that makes no claim of its own and instead points at an artefact, such as a solution or a context expressed as a noun phrase. Core GSN Assumption An assumption, rendered as an oval with the letter 'A' at the top- or bottom-right, presents an intentionally unsubstantiated statement. Core GSN oval Assurance Case A reasoned and compelling argument, supported by a body of evidence, that a system, service or organisation will operate as intended for a defined application in a defined environment. Arguments and evidence intended to demonstrate that a system meets its assurance requirements. Core GSN Catalogue A pattern catalogue may be created to collate a series of patterns; where such a catalogue is created the structure and format of the definition should be consistent and each pattern’s definition should have a unique {pattern identifier}. Argument Pattern Extension Context A context, rendered as shown left, presents a contextual artefact. This can be a reference to contextual information, or a statement. Core GSN rounded rectangle Defeater Dialectic Element The source of challenge being applied; can be directed at any part of an argument. A defeater (goal or solution) can challenge any element in a goal structure, e.g. goal, solution, strategy, context, assumption, justification. Membership of this class is only meant to be inferred, not asserted! Please do not add individuals to this class manually (i.e., assertions). The goal and solution statements should be clearly expressed such that the crux of the challenge is unequivocally communicated. Thus, the link between the part of the argument that is being challenged (target) and the dialectic element (source) is self-evident. Dialectic Extension GSN Element Goals, solutions, strategies, contexts, assumptions and justifications form the principal elements of GSN. Core GSN Goal Claim (Claim is) A proposition being asserted by the author that is a true or false statement. A goal, rendered as a rectangle, presents a claim forming part of the argument. Core GSN rectangle Instantiation Data Reference This symbol indicates that the GSN argument below the attached element is to be instantiated as a template argument. It provides a reference to the information used to instantiate the template argument. Argument Pattern Extension hollow triangle Justification A justification, rendered as an oval with the letter 'J' at the top- or bottom-right, presents a statement of rationale. Core GSN oval Module Goal structures can be partitioned into separate, but interrelated, modules. This can allow the division of an overall goal structure into separate goal structures focusing on particular aspects of the overall argument. A module may contain one or more arguments and may contain other modules. Modular Extension a rectangle with a second smaller rectangle adjoining at the top left Pattern [OntoGSN] A reusable argument structure, accompanied by a description that defines its intent and the constraints on its use, from which concrete arguments are instantiated. Argument Pattern Extension Relationship [OntoGSN] A link between GSN elements treated as an individual in its own right, carrying its subject, object and type, so that the link itself can be decorated and described. Core GSN Relationship with Confidence [OntoGSN] A relationship carrying an assurance claim point, whose associated confidence argument documents the reasons for having confidence in the relationship between two elements. The corresponding argument could be located in a paragraph of accompanying text, a goal in the local argument, or a goal in a separate module. Confidence Argument Extension Solution A solution, rendered as a circle, presents a reference to an evidence item. Core GSN circle Strategy A strategy, rendered as a parallelogram, describes the inference that exists between a goal and its supporting goal(s). Core GSN parallelogram Template A template argument is a special case of a pattern argument. It uses the core GSN and argument pattern extension to construct an argument structure which requires no further development. Argument Pattern Extension View The argument view depicts the argument inside an individual module. Modular Extension applicability The applicability section should state under what circumstances the pattern can be applied, making clear the assumptions and principles underlying the pattern to avoid inappropriate application in a mismatched context. This section should record what contextual information is required in order to apply the pattern. Argument Pattern Extension argument type [OntoGSN] Defines the kind of argument this is: a risk argument (i.e., the main content of assurance), a confidence argument for an assurance claim point, a compliance argument (undefined in the normative standard), or a dialectic argument. Confidence Argument Extension associated with [OntoGSN] Links a relationship or an artefact reference to the confidence argument provided for it. Confidence Argument Extension assurance claim point An Assurance Claim Point (ACP) can be used in GSN to indicate that a confidence argument is associated with an assertion in a risk argument. Confidence Argument Extension solid square attached to [OntoGSN] Links an instantiation data reference to the element or template argument it annotates. Argument Pattern Extension dotted line An away assumption repeats an assumption presented in another argument module and is typically used only in Contract Modules. An away context repeats a reference to context presented in another argument module. An away goal reference repeats a claim presented in another argument module. An away justification repeats a justification presented in another argument module and is typically used only in Contract Modules. An away solution repeats a reference to evidence items presented in another argument module. away An away element reference repeats a claim or evidence presented in another argument module. Modular Extension bisecting line in the lower half challenges Allows a Challenge to any GSN entity to be documented. A goal, (core element) can be used in a dialectic context to assert a challenge to part of the argument. A solution, (core element) can be used to present a reference to an evidence item that asserts a challenge to part of the argument. A challenge must be levied against the appropriate aspect of the goal structure. Dialectic Extension dashed line with an open arrowhead choice A GSN choice can be used to denote possible alternatives in satisfying a relationship. Argument Pattern Extension solid diamond collaboration The collaboration section should describe how elements of the pattern work together to achieve the desired effect, particularly where there are links that are not readily apparent from the argument structure. Argument Pattern Extension consequences The consequences section should make clear what work remains after the pattern has been applied. This should highlight where further support to the argument is required, and assumptions that need to be discharged. Argument Pattern Extension consistent with By making the relationship to the away goal the author is asserting not only the inference of support for the parent goal, but also that the context in which the away goal is declared is consistent with the context and assumptions in scope for the parent goal. Modular Extension contains [OntoGSN] Relates a container (e.g., an assurance case, argument, module, catalogue or pattern) to its components (e.g., elements, arguments, patterns or artefacts). Core GSN contract A contract module is a special type of module that controls the relationship between argument module interfaces using arguments to define how a goal in one module is supported by one or more goals in one or more other modules. A contract may be described in textual form (e.g. as a table) or for more complex relationships may be described within a contract module using GSN. Contract modules can be used in the support relationship between modules to aid decoupling. The de-coupling by use of a contract permits argument module construction in cases where the eventual source of support for an argument is unknown at the time of authoring or can be changed for example through re-use or planned product improvement or reconfiguration. Modular Extension a rectangle with two smaller rectangles (of equal size to each other) adjoining at the top left and bottom right core or extension Indicator of the sourcing section in the GSN Community Standard v3. Defeated Relationship indicates that the relationship is defeated. The Defeated decorator can be applied to any of the GSN relationships. defeated This decorator symbol indicates that the element is defeated. The Defeated decorator can be applied to any of the GSN elements. Dialectic Extension cross (‘X’) superimposed on a GSN element or relationship depicts The argument view depicts the argument inside an individual module. Modular Extension examples It may be useful to provide example illustrations of the application of the pattern, particularly for more abstract patterns. Illustrations should include a typical case and can be supplemented with atypical cases where more than one example is provided. Argument Pattern Extension final [OntoGSN] Determines whether this is the delivered version of the argument or pattern, in which no element remains uninstantiated or undeveloped. Argument Pattern Extension implementation The implementation section should communicate how the application of the pattern is carried out e.g. the order in which elements should be developed; communicate hints or techniques that may ease successful application; highlight common or recognised pitfalls with the application of the pattern; and record potential misinterpretation of the terms or concepts in the pattern. Argument Pattern Extension in context of InContextOf, rendered as a line with a hollow arrowhead, declares a contextual relationship. Core GSN line with a hollow arrowhead in doubt The dialectic challenge within this structure asserts that if the claim presented in Goal CG1 is true then this is sufficient to establish that the claim in Goal G1 in the original structure is in doubt. Dialectic Extension in module The module an element belongs to, whether the element sits in an argument the module contains or in a module nested inside it. Inferred, never authored. A module contains arguments and other modules, so the module an element belongs to is always reached in two steps or more. This property names the result of that traversal so that the rules of the Modular Extension can state it in one atom. It is derived by the Module Membership and Nested Module Membership rules. Modular Extension true inferred only [OntoGSN] Marks a property that a rule derives and that a case never asserts. Core GSN instantiation of [OntoGSN] Relates an argument or element to the pattern it was instantiated from. Argument Pattern Extension intent The intent statement should state clearly what the pattern aims to achieve. Argument Pattern Extension known uses It may be useful to provide references to known applications of the pattern. These can serve as additional examples. Argument Pattern Extension maximum cardinality [OntoGSN] The upper bound on how many instances of the related element this relationship stands for. Argument Pattern Extension text minimum cardinality [OntoGSN] The lower bound on how many instances of the related element this relationship stands for. Argument Pattern Extension text motivation The motivation statement can be used to state why the pattern was created. It could be expressed in terms of previous experiences e.g. as the abstraction of a successfully presented argument, or challenges addressed e.g. argument topics that are often incompletely or poorly addressed. Argument Pattern Extension multiple [OntoGSN] Determines whether the relationship stands for multiple instantiations rather than a single one. Argument Pattern Extension solid ball off-diagram [OntoGSN] Determines whether the argument at this element continues in, or is a continuation from, a separate diagram. Core GSN optional Optional instantiation means that the relationship and the argument below may or may not be instantiated. Argument Pattern Extension hollow ball participants The participants section augments the structure by providing a description of each element. This can provide more complete descriptions, clarify the role of the element in the overall argument and emphasise the aspects that require development or instantiation. Argument Pattern Extension public This indicates that the element is publicly visible in one or more interfaces of the module and can be referenced as an away element. Modular Extension miniature module symbol superimposed on an element at the top right published [OntoGSN] Determines whether the argument or pattern is in its published form, in which the undeveloped decorator is not permitted. Argument Pattern Extension refers to [OntoGSN] Relates an artefact reference or an instantiation data reference to the artefact it points at. Core GSN related to This section can be used to reference patterns that are related e.g. addressing the same intent in a different context. Argument Pattern Extension relationship type An evidential relationship is a declared relationship between a claim and an evidence item by which the claim is substantiated. An inferential relationship is a declared inference between claims in the argument. A contextual relationship draws attention to explanatory contextual information. SupportedBy relationships – represented by lines with solid arrowheads – indicate inferential or evidential relationships between elements. InContextOf relationships – represented as lines with hollow arrowheads – declare contextual relationships. Core GSN rendered as Core GSN statement [OntoGSN] The text the element asserts, written to the grammatical rules the standard sets for GSN statements. Core GSN structure The structure uses the structural and element abstraction notations to present the pattern, clearly indicating where the argument needs to be further developed or populated with details to instantiate the pattern for a specific case. Argument Pattern Extension structured A particular kind of argument where the relationships between the asserted claims, and from the evidence to the claims, are explicitly represented. Core GSN substituted by There may be occasions when a goal or strategy requires fuller justification than can be provided within the confines of a GSN justification element. In such cases, an away goal can be substituted for the justification. Modular Extension supported by SupportedBy, rendered as a line with a solid arrowhead, allows support relationships between elements to be documented. Core GSN line with a solid arrowhead to be supported by contract Support for the claim presented by the attached goal is intended to be provided from an argument in another module linked by an as-yet-undisclosed contract. Modular Extension attached centrally immediately below the goal to which it relates top (goal) A GSN Goal that presents the pinnacle claim in an argument. It is ‘top’ in terms of the argument hierarchy, rather than necessarily its physical layout. There may be more than one top goal in a GSN structure. The top goal presents the overall claim asserted by the author and it is up to the reader to determine their belief that it is adequately supported. Core GSN transitively challenges [OntoGSN] Relates an element to every element that it reaches through a chain of one or more challenges. Inferred, never authored. It is derived by the Challenge Closure rule, and the Challenge Cycle rules read it. Dialectic Extension true transitively in context of [OntoGSN] Relates a module to every module that it reaches through a chain of one or more in-context-of links between modules. Inferred, never authored. It is derived by the Module Context Closure rule, and the Module Context Cycle rules read it. Modular Extension true transitively supported by [OntoGSN] Relates an element to every element that it reaches through a chain of one or more supported-by links. Inferred, never authored. It is derived by the Support Closure rule, and the Support Cycle rules read it. Core GSN true true [OntoGSN] Marks whether the claim in the element or relationship is determined (e.g., by the auditor or some process) as correct or not. Core GSN undeveloped Undeveloped element decorator, rendered as a hollow diamond applied to the bottom centre of an element, indicates that a line of argument has not been developed. Argument Pattern Extension hollow diamond uninstantiated The attached element remains to be instantiated: at some later stage the abstract element needs to be replaced with a more concrete instance. Argument Pattern Extension hollow triangle valid [OntoGSN] Marks whether the element is determined (e.g., by a rule or a manual evaluation) to be consistent with the argument, or otherwise correct with respect to the GSN argument syntax. Core GSN view type [OntoGSN] Determines whether the view shows the argument or the module architecture. Modular Extension false true Support Closure Core GSN false false true true Inferential Relation Core GSN false true true Challenge Cycle Relationship Invalidation Dialectic Extension true Contract Violation Relation Modular Extension false false GSN assumptions provide additional information necessary for the correct understanding of the argument. This information is stated as fully as necessary, using complete sentences in the form noun phrase + verb phrase. true Contract Support Invalidation Modular Extension true true Support Cycle Invalidation Core GSN true true true inferential true false true true Context Inheritance Core GSN false true false false contextual true true true true false true Template Undeveloped Invalidation (A) Argument Pattern Extension risk architecture false dialectic true Strategy Confidence Relation Confidence Argument Extension inferential true Cross-Module Support Modular Extension GSN goals document the claims made in the argument (i.e. premises and conclusions). Each goal shall contain a single goal statement, expressed as a proposition in the form of a noun phrase + verb-phrase sentence. contextual true Away Goal Invalidation Modular Extension true Relation False Propagation Core GSN true Template Undeveloped Invalidation (B) Argument Pattern Extension true Contradictory Goal Truth Core GSN dialectic true Support Relation Creation Core GSN true false true Confidence Relation Creation Confidence Argument Extension true false true 1 fortiss GmbH true true Support Cycle Relationship Invalidation Core GSN true Solution Propagation (False) Core GSN true Goal Top Flag Core GSN true dialectic false true Duplicate ACP Identifier Invalidation Confidence Argument Extension false true false true Inferential Relation (Goal) Core GSN false false false true Evidential Relation Core GSN true Contract Relation Invalidation Modular Extension true Goal-Strategy Confidence Confidence Argument Extension true Challenge Defeat Dialectic Extension evidential true Module Membership Modular Extension false false true Module Context Cycle Relationship Invalidation Modular Extension false false false true Context Consistency Modular Extension false true Module Context Closure Modular Extension GSN strategy statements describe the reasoning that connects parent goals and their supporting goals, but the core claims and the structure connecting those claims remain unchanged. Strategy statements contain a brief description of the argument approach. false false true Module Support Propagation Modular Extension false true GSN solutions make no claim, but are simply references to evidence items that provide support for a particular claim. They shall therefore be stated as noun-phrases. true true Context Relation Creation Core GSN true Assumption False Propagation Core GSN inferential argument true Final Pattern Invalidation Argument Pattern Extension 1 true Defeater Declaration Dialectic Extension true Challenge Cycle Invalidation Dialectic Extension confidence false true Cross-Module Away Context Modular Extension true Core GSN true Assumption Invalidation Core GSN true Challenge Doubt Dialectic Extension true true Module Context Cycle Invalidation Modular Extension true true Mixed Support Invalidation Core GSN true Solution Confidence Relation Confidence Argument Extension true Duplicate Identifier Invalidation Modular Extension false true Challenge Closure Dialectic Extension true true Nested Module Membership Modular Extension true Undeveloped Defeat Dialectic Extension true Cross-Module Away Support Modular Extension true Solution Propagation (True) Core GSN false true false true true true true false false false 1 true Defeated Invalidation Dialectic Extension true true false evidential true Challenge Chain Invalidation Dialectic Extension true Contextual Relation Core GSN true Public Context Propagation Modular Extension true true Goal Confidence Relation Confidence Argument Extension true Two kinds of GSN context statement exist. Where a context statement draws attention to explanatory contextual information (such as the definition of some term), this information shall be stated briefly using complete sentences of a noun-phrase + verb-phrase structure. Where a context statement is a reference to an artefact of some kind, which informs the reasoning step, the context statement shall be expressed as a noun phrase. true true false true true true Public Contract Invalidation Modular Extension 1 true Context Contract Invalidation Modular Extension The corresponding argument could be located in a paragraph of accompanying text, a goal in the local argument, or a goal in a separate module. Confidence Argument Extension true true true Challenge Relation Creation Dialectic Extension true Substitution Invalidation Modular Extension true Contract Activation Modular Extension false false true true Module Context Propagation Modular Extension confidence GSN justifications provide additional information necessary for the correct understanding of the argument. This information is stated as fully as necessary, using complete sentences in the form noun phrase + verb phrase. true