The special symbol ~ at the beginning is allowed, but it could lead to issues in mapping implementations because most script and programming languages do not allow it.

The mapping class was introduced by SYSML2-139.

The section containing the tables about the elements that have no mapping defined should start with a text that briefly describes the purpose of the section.

Some entries in the mapping overview tables show duplicate entries in the SysML v2 column.

The table in the mapping chapters' overview sections sometimes has no information about the SysML v2 target element. There should be a target element or a note that the rationale for not having a target element can be found in the following section that lists the elements that are not mapped with a justification.

Decision/MergeNodes are (indirectly) typed by KerML:Decision/MergePerformance (via specialization of Actions::Action::decisions/merges), which KerML Clause 9.2.9.1 (Control Performances Overview) requires:

Successions going out of Steps typed by DecisionPerformance or its specializations must:
• ...
• be included in a Feature of its featuringBehavior that unions (see 7.3.2.7) all the outgoing Successions, and is bound to the outgoingHBLink of the Step (see 7.3.4.6 on feature chaining).

Successions coming into Steps typed by MergePerformance or its specializations must:
• ...
• subset a Feature of its featuringBehavior that unions all the incoming Successions, and is bound to the incomingHBLink of the Step.

while constraints in 8.3.16.7 (DecisionNode) and 8.3.16.13 (MergeNode) say

checkDecisionNodeOutgoingSuccessionSpecialization
All outgoing Successions from a DecisionNode must subset the inherited outgoingHBLink feature of the DecisionNode.
sourceConnector->selectByKind(Succession)-> forAll(subsetsChain(this,
resolveGlobal("ControlPerformances::MergePerformance::outgoingHBLink")))

checkMergeNodeIncomingSuccessionSpecialization
All incoming Successions to a MergeNode must subset the inherited incomingHBLink feature of the MergeNode.
targetConnector->selectByKind(Succession)-> forAll(subsetsChain(this,
resolveGlobal("ControlPerformances::MergePerformance::incomingHBLink")))

with similar text in 8.4.12.4 (Control Nodes) under Decision / Merge Nodes. These constraints allow outgoing/incomingHBLink to have values that are not identified by outgoing/incoming successions when none of the successions is traversed. The KerML pattern above introduces a feature unioning the successions and binds it to a chain through decision/merge to outgoing/incomingHBLink, ensuring the HB links are identified by the successions. See Annex A.3.7 (Timing for behaviors, Decisions and merges) for an example, at the end of the model to be executed (first code listing), under "Decision and merge timing constraints".

Some multiple specializations in the libraries might be intended to be intersections, including feature specializations. For example, from SYSML2-490, under Actions::Actions

action sendSubactions: SendAction[0..*] :> subactions, sendActions {
  doc /* * The subactions of this Action that are SendActions. */ }

action acceptSubactions: AcceptAction[0..*] :> subactions, acceptActions {
  doc /* * The subactions of this Action that are AcceptActions. */ }

Clause 8.4.5.2 (Occurrence Usages) says

If an OccurrenceUsage has a non-null portionKind, then it is also required to have a portioningFeature with the same portionKind. The following semantic constraints apply to a PortioningFeature:
...

and the code example at the end of 8.4.5.2 has comments identifying some features as "Portioning", with text below it referring to portioningFeature

However, portioningFeature doesn't appear in Figure 12 (Occurrence Definition and Usage) or anywhere else in the document.

The approved resolution to KERML-195 adds a note to the ItemFlowFeature production in the KerML concrete syntax grammar on properly setting the direction of the synthesized feature. A similar note should be added to the FlowFeature production in subclause 8.2.2.13.4 of the SysML textual notation grammar.

The approved resolution to SYSML2-28 includes adding the constraint validateTriggerInvocationExpressionAfterArgument, which requires:

If a TriggerInvocationExpression has kind = after, then it must have an argument Expression with a result that conforms to the type ISQ::DurationValue.

However, in a typical relative time trigger such as, e.g., after 10[SI::s], the result of the expression 10[SI::s] is not a DurationValue. Rather it is a ScalarQuantityValue whose mRef is the DurationUnit SI::s. Therefore, this example time trigger violates validateTriggerInvocationExpressionAfterArgument as specified in the resolution to SYSML2-28.

The approved resolution to KERML-20 adds the validation constraint validateFeatureValueOverriding that "All Features directly or indirectly redefined by the featureWithValue of a FeatureValue must have only default FeatureValues." This constraint causes problems for two models in the Systems Model Library. These library models do not actually violate the constraint, but using the models as intended my violate the constraint.

1. In the action definition Actions::AcceptAction, the inout paramater payload is redefined with a feature value binding it to aState.aTransition.aPayload. However, when an accept action is parsed with a change or time trigger, the payload is implicitly bound to the generated change or time signal, and this violates the validateFeatureValueOverriding constraint.
2. In the analysis case definition AnalysisCases::AnalysisCase:
   • The subject of the objective of AnalysisCase is bound to the result parameter of the AnalysisCase. However, when specifying an analysis case, it is sometimes convenient to compute a check of the case objective by evaluating it on a given subject value. However, the binding of such an subject argument then violates the validateFeatureValueOverring constraint.
   • The result parameter is bound to the result of the AnalysisCase::resultEvaluation calculation feature. However, when defining an analysis case in a user model, it is natural to bind the computation of the result of the case to the result parameter as a feature value. But this then violates the validateFeatureValueOverriding constraint.

The end features of MessageConnection, FlowConnection and SuccessionFlowConnection in the standard library package Connections are typed as Occurrences, but they are currently syntactically reference usages, not occurrence usages. However, the abstract syntax for EventOccurrenceUsage requires that its referenced eventOccurrence must actually be an OccurrenceUsage. This means that the source and target ends of, e.g., a message, if inherited from MessageConnection and not redefined, cannot be referenced by EventOccurrenceUsages, which prevents an intended use in "sequence diagram" modeling.

In 8.3.17.6 StateUsage, the description of checkStateUsageSpecialization is

A StateUsage must directly or indirectly specialize the StateUsage States::stateActions from the Systems Model Library.

but the OCL is

specializesFromLibrary('States::StateAction')

which requires specialization of StateAction, not stateActions.

In the SysML Specification, 8.3.16.5 AssignmentActionUsage, the constraint deriveAssignmentActionUsageReferent states that "The referent of an AssignmentActionUsage is the first Feature that is the memberElement of a ownedMembership that is not an OwningMembership." However, according to the BNF in 8.2.2.16.5 Assignment Action Usages, the intended referent of an assignment is parsed as a FeatureChainMember, and, for an actual chain of more than one Feature, the chaining Feature is owned by the AssignmentActionUsage via OwningMembership. Therefore, it will not be identified as the referent of the assignment according to the current derivation.

The approved resolution to SYSML2-28 included adding the constraint validateTriggerInvocationExpressionWhenArgument, which requires:

If a TriggerInvocationExpression has kind = when, then it must have an argument Expression with a result that conforms to the type ScalarValues::Boolean.

However, the argument to a when trigger is not supposed to be an Expression with a Boolean result. Rather, it is an Expression whose result is the Evaluation of an Expression whose result is Boolean. That is, a trigger like when x > 0 is parsed as TriggerWhen({x > 0}), not as TriggerWhen(x > 0). So all properly parsed when triggers will violate validateTriggerInvocationExpressionWhenArgument as specified in the resolution to SYSML2-28.

In the Systems Model Library, the features Actions::Action::acceptSubactions and Actions::Action::sendSubactions should subset Actions::acceptActions and Actions::sendActions, respectively.

In the SysML Specification, 7.6.7 Variations and Usages states “A variation is always abstract, so the abstract keyword is not used on a variation.” And, indeed, the textual notation BNF in 8.2.2.6.1 Definitions and 8.2.2.6.2 Usages allows either the abstract or variation keyword to be applied to a definition or usage declaration, but not both. However, there are no constraints in the abstract syntax subclauses 8.3.6.2 Definition or 8.3.6.4 Usage to enforce this.

Subclause 9.8.8 on the Time package in the Quantities and Units Domain Library does not include documentation of defaultClock, which is in the normative library model.

In 9.4.3.2.5 Sample (in the Sampled Function model in the Analysis Domain LIbrary), the feature calculation has type CalculationUsage. However, in the actual library model, calculation is a CalculationUsage, which means it should have the base library definition Calculation as its type, not the abstract syntax element CalculationUsage

The enumeration definitions VerdictKind and VerificationMethodKind, which are in the normative Systems Model Library package VerificationCases, are missing from Systems Model Library subclause 9.2.16 Verification Cases in the SysML Specification.

1. Subclause 9.8.1 paragraph 2 sentence 2, contains a typo: "The library also provides enables the specification ..." should read "The library also enables the specification ...", i.e. delete "provides".
2. Subclause 9.8.2.1 example 1 under Free versus Bound Quantities and Vector Spaces, contains a typo: "Displacement vector (free) and the position vector (bound), ..." should read "Displacement vector (free) and position vector (bound), ...", i.e. delete "the".

The issue SYSML2-241 is merged into SYSML2-240. Both issues are approved. The resolution of SYSML2-240 does not consider the issue SYSML2-241.

In the Analysis Domain Library model TradeStudies::TradeStudy, the requirement definitions MinimizeObjective and MaximizeObjective explicitly redefine the parameter best from the TradeStudyObjective definition they specialize, but do not declare any other parameters. However, this violates the checkFeatureParameterRedefinition constraint, which requires that parameters be redefined in order. And, if the implied redefinition is added to the actual first parameter selectedAlternative, then this also violates the validateRedefinitionDirectionConformance constraint (add by the approved resolution to KERML-20), because best is an out parameter, while selectedAlternative is an in parameter.

In 8.3.20.9 RequirementUsage, the checkRequirementUsageObjectiveRedefinition constraint requires that "A RequirementUsage whose owningFeatureMembership is a ObjectiveMembership must redefine the objectiveRequirement of each CaseDefinition or CaseUsage that is specialized by the owningType of the RequirementUsage." However, the objectiveRequirement property of a CaseDefinition (see 8.3.21.2) or a CaseUsage (see 8.3.21.3) is derived to be only the owned objective of the case. This means that, if a case declares an owned objective, but specializes a case with an inherited objective, then checkRequirementUsageObjectiveRedefinition will actually be satisfiable.

Sections 7.7.4 - 7.7.14 and Section 7.8.5 should contain the introductory sentence:

This chapter lists all mapping specifications of <namespace> model elements.

For example, as in Section 7.7.3:

This chapter lists all mapping specifications of UML4SysML::Activities model elements.

The sentence "The justifications for the elements without mapping are given in view link does not exist" in the State Machines overview sentence does not make sense and should be removed.

The sentence "The justifications for the elements without mapping are given in view link does not exist" in the Classification overview sentence does not make sense and should be removed.

Time and change triggers for an accept action are supposed to be parsed as a TriggerInvocationExpression with a single argument: for a time trigger, the argument is a duration or time instant, while for a change trigger it is a boolean expression. However, the textual notation BNF for TriggerExpression in 8.2.2.16.4 is not properly parsing the textual notation as an invocation with arguments. As a result, the intended argument expression for the TriggerInocationExpression will not actually be recognized as an argument of the invocation.

In the textual notation grammar, RequirementConstraintUsage produces a ConstraintUsage, but the first alternative in the production allows the ConstraintUsage to have a RequirementBody. The RequirementBody production allows kinds of declarations (such as subjects and actors) that are not valid in the body of a ConstraintUsage (because of validation constraints such as validateSubjectMembershipOwningType, validateActorMembershipOwningType, etc.). There is no point in syntactically allowing owned members that are then invalid, so the first alternative in RequirementConstraintUsage should have a CalculationBody (like the second alternative) rather than a RequirementBody.

The production for <SourceSuccessionMember > has "+" and it should be "+="

SourceSuccessionMember : FeatureMembership =
'then' ownedRelatedElement + SourceSuccession

The production for <SourceEndMember> has "+" and it should be "+="

SourceEndMember : EndFeatureMembership =
ownedRelatedElement + SourceEnd

The option for <PrefixComment> has been deprecated, but is still an option for AnnotatingElement. Remove PrefixComment.

AnnotatingElement =
  Comment
| PrefixComment
| Documentation
| TextualRepresentation
| MetadataUsage

Prior error report on this production can be replaced with this error report.

The issue is with the production:

FeatureTyping = OwnedFeatureTyping | ConjugatePortTyping

The correct conjugate nonterminal should be <ConjugatedPortTyping>

In the production:

FeatureTyping = OwnedFeatureTyping | ConjugatePortTyping

There is no corresponding production for the non-terminal <ConjugatePortTyping>.
<ConjugatedPortDefinitionMember> or <ConjugatedPortDefinition> may be correct for <FeatureTyping>.

The current specification:

SourceSuccessionMember : FeatureMembership =
    'then' ownedRelatedElement + SourceSuccession

SourceSuccession : SuccessionAsUsage =
    ownedRelationship += SourceEndMember

    SourceEndMember : EndFeatureMembership =
ownedRelatedElement + SourceEnd

is incorrect. It should be:

SourceSuccessionMember : FeatureMembership =
    'then' ownedRelatedElement += SourceSuccession

SourceSuccession : SuccessionAsUsage =
    ownedRelationship += SourceEndMember

    SourceEndMember : EndFeatureMembership =
ownedRelatedElement += SourceEnd

The approved resolution for issue SYSML2-180 uses the mapping class GenericToItemUsage_Mapping which does not exist. It seems that it was overseen to add the creation of the mapping class to the revised text of the resolution.

The generic mapping class GenericToItemDefinition_Mapping specializes GenericToDefinition_Mapping. However, it should specialize GenericToOccurrenceDefinition_Mapping which is a subclass of GenericToDefinition_Mapping as well as ItemDefinition specializes OccurrenceDefinition.

In example "Interface as Node" remove arrow heads from the nested connections, and move arrow head between pa and pb to end of line, add message of item1:Item1 from pa to pb to the interface2 usage in the textual notation. Also add open curly bracket directly after interface2, and closing curly bracket after the ellipsis.

In example "Flow as Node" check whether flow from source :> action1.item1 should be reference subsetting? Add keyword from to the nested flows.

In example "Binding Connection" «ref part» part4R should use the graphical notation as specified in the graphical BNF in subclause 8.2.3.11.

In example "Variants Compartment" textual notation should include part def PartDef1, and item def ItemDef1, and also part1 : PartDef1 and item1 : ItemDef1.

Example "Subsetting" is missing specification of the perform action action1 : Action1 that is shown as inherited in the graphical notation. Add part def Part1 in textual notation from preceding example "Usage Definition".

The approved resolution to SYSML2-28 included the adding of the constraint validateAssignmentActionUsageArguments, which requires that an AssignmentActionUsage have two arguments. However, in the SysML Specification, 8.2.2.16.5 Assignment Action Usages, the AssignmentTargetParameter is optional for an AssignmentNodeDeclaration. An AssignmentActionUsage parsed without a target parameter argument will then fail the validateAssignmentActionUsageArguments.

In 7.16.9 Assignment Action Usages it states that "If the target expression of an assignment action usage is omitted, then the target is implicitly the occurrence owning the assignment action usage." However, there is no semantic constraint enforcing this, so it is not clear how the informal statement is supposed to be realized.

A requirement should include a text body to capture the shall statement or other human readable requirement statement. The doc annotating element is one way to accomplish this. However, a doc element on a requirement definition is inherited by its requirement usages, but it cannot be redefined on its usage. (Note: The texts of a RequirementUsage are the bodies of the documentation of the RequirementUsage.)

The proposal is to add a distinguished attribute to capture the text body of a requirement that would replace the derived text attribute/documentation. This distinguished attribute can be redefined. This avoids a requirement usage from having both the original text in the requirement definition and the modified text in the usage.

The concrete syntax should be updated accordingly.

The OCL for the constraints deriveViewDefinitionViewCondition and deriveViewUsageViewCondition are both

viewCondition = featureMembership->
    selectByKind(ElementFilterMembership).
    condition

This is clearly wrong, since ElementFilterMemberships are not featureMemberships.

In addition, the description of the deriveViewUsageViewCondition constraint refers to ViewDefinition instead of ViewUsage, as do the descriptions of deriveViewUsageSatsifiedViewpoint, deriveViewUsageViewRendering and validateViewUsageOnlyOneViewRendering. (And the description of deriveViewUsageExposedElement is missing.)

The transformation does not map the Parameter::isStreaming.

The mapping of a Unit and a QuantityKind is not covered by the transformation yet.

According to the SysML Specification, 8.2.2.16.4 Send and Accept Actions, the general textual notation for a send action has the form

send payloadExpression via senderExpression to receiverExpression

In this syntax, the via and to parts are optional, but the payloadExpression is not. Since the result of the required payloadExpression is bound to the payload parameter of the send action, this makes it difficult to model a case in which, e.g., it is desired use a flow to provide the value of the payload, rather than the result of an expression. It also makes it difficult to model a general send action with the payload not specified (or defaulted), with the actual payload bound in a specialization of the general action.

While it is possible to get around these limitations by modeling the send action using a regular action usage typed by Actions::SendAction, this is no longer syntactically a send action usage and so, e.g., would not be render as such in the graphical notation. It would be better if the textual notation allowed the payloadExpression to be optional, while still declaring syntactic send action usage.

In example "Part performs a reference action (action1) that reference subsets another action (action3)" replace «perform action» action1 with «perform» action2, and «action» action3 : Action3 with «action» action2 : Action2, and adapt the textual notation accordingly. This also makes it consistent with the preceding example.

Example "Individual Occurrence" should include individual def from preceding example, and rename occurrence1 to occurrence1-1.

The descriptions in 8.3.16.9 (ForLoopActionUsage) and 8.3.16.18 (WhileLoopsActionusage) refer to "bodyClause", but in Figure 28 (Structured Control Actions) the association end for this (presumably) is called "bodyAction".

The OCL for both of the constraints validateDefinitionVariationSpecialization and validateUsageVariationSpecialization is:

isVariation implies
    not ownedSpecialization.specific->exists(isVariation)

These constraints should be checking Specialization::general, not Specialization::specific. In addition, the type of both specific and general is Type, which doesn't have an isVariation property. Only Definition and Usage types have such a property.

The intent of "initializer" classes is to factorize the opeations that provide default values for the properties of a target class so that it can be used for both mapping and factory classes. Initializers that do not generalize both a mapping and a factory class are useless and should be remove for clarity

The redefinition of ownedRelationship() is missing the "class" part, i.e. what is defined in its Class aspect

The use of the term feature in the document is inconsistent with the ISO standard definition

Feature - ISO/IEC/IEEE 29148:2018
A feature is an externally desired service by the system that may require a sequence of inputs to effect the desired result.

• For example, in a telephone system, features include
  • local call,
  • call forwarding and
  • conference call.
• Each feature is generally described in a sequence of stimulus response pairs.

I.e. a feature of a system is about externally visible system behaviour

Feature is a generic term and has many different meanings in different fields/contexts.
However in System Engineering, the word is usually used as defined by the ISO standard (above).

The use of the term 'feature' in the SysML 2 document is definitely NOT consistent with the ISO definition.
Suggestion for a better term in the SysML 2 would be something like Member, Attribute, Aspect, Detail.

Informal specification of requirements is realized as body of the documentation.
Informal requirement specification often contains text formatting and images as illustrations. To facilitate exchange of requirements between different organizations and proper rendering, the used formatting language, the relative root path for included images and their allowed formats have to be aligned.

• add optional 'language' keyword to doc
• define the folder containing the sysml file as root for references made from documentation elements within this file

To provide guidance for users on common formatting

• reference jpg and png as suggested image formats
• reference markdown "md" or other low-complex language as suggested formatting language

example:
requirement def SomeRequirement

Definition elements incorrectly appear in graphical BNF productions for interconnection-element. Remove the following from interconnection-element productions: part-def in 8.2.3.11, port-def in 8.2.3.12, connection-def in 8.2.3.13, constraint-def in 8.2.3.19, requirement-def and concern-def in 8.2.3.20, viewpoint-def and view-def in 8.2.3.25.

Concern_Mapping is a main mapping that calls ConcernOwningMemberships_Mapping in its ownedRelationship() operation, which itself calls ConcernDocumentation_Mapping. However, the one defined in its ancestor Comment_Mapping should do the job without them.
The redefinition should then be removed and both ConcernOwningMemberships_Mapping and ConcernDocumentation_Mapping are useless and should be replace by a simpler version of the ownedRelationship() operation.

The transformation ignores the entry, do, and exit behavior of a state.

The mapping of ObjectFlow in combination with JoinNodes is not covered yet by the transformation.

The mapping of ObjectFlow in combination with DecisionNodes including the decisionInput is not covered yet by the transformation.

In SysML v1, an output value of an action that is an input value of more than one action, is often modeled by an object flow and fork node which create object tokens pointing to the value.

The mapping of ObjectFlow in combination with ForkNodes is not covered yet by the transformation.

In the textual notation, a time event can be represented by an accept action with an at or after condition. The example below is from the vehicle model.
transition normal_To_maintenance
first normal
accept at maintenanceTime
then maintenance;

In the textual notation, a change event can be represented by an accept action with a when condition. The example below is from the vehicle model.
transition normal_To_degraded
first normal
accept when senseTemperature.temp > Tmax
do send OverTemp() via targetPort
then degraded;

A UML4SysML::ConstraintProperty is currently mapped to a ItemUsage, but should be an AssertConstraintUsage.

The SysML v1 properties like part property, are concepts, but not stereotypes or metamodel elements. Therefore, they are explicitly covered by a mapping class or are listed in the overview tables.

Add a documentation in section 7.8.4.1 that describes how the different SysML v1 property concepts are mapped to SysML v2.

Property_Mapping maps properties typed by a Class or Interface. The target element should be ItemUsage instead of Feature.

The name of the mapping class is misleading. It creates the impression that it maps all kinds of properties, but it only covers the cases where a Class or Interface types properties. Rename the mapping class to PropertyTypedByClassInterface_Mapping.

The specialized mapping classes ConstraintParameter_Mapping, Port_Mapping, and Part_Mapping should specialize PropertyCommon_Mapping instead of Property_Mapping.

The table headers state that the rows list SysML v1 and v2 concepts. Actually, they only list stereotype and metamodel elements but not all the concepts. For example, the part property is not listed because it is not a SysML v1 stereotype but only a concept.

UML4SysML::Class is currently mapped to OccurrenceDefinition, but should be ItemDefinition.

Part properties with AggregationKind::none or shared are mapped to Feature, but should be a PartUsage with isComposite=false.

The mapping of a ValueType is identical to the mapping of a DataType. Therefore, there is no explicit mapping class for ValueType. However, that hides the information of the mapping of ValueTypes in the transformation specification.

The mapping classes InformationFlowEnd_Mapping, InformationFlowFeatureTyping_Mapping, and InformationFlowEndFeatureMembership_Mapping updated by SYSML2-180 should use more specialized GenericTo mapping classes instead of the GenericToElement_Mapping class:

InformationFlowEnd_Mapping => GenericToFeature_Mapping
InformationFlowFeatureTyping_Mapping => GenericToFeatureTyping_Mapping
InformationFlowEndFeatureMembership_Mapping => GenericToFeatureMembership_Mapping

The description of the TimeEvent_Mapping class is a note from the development team instead of a description text.

The description of the ChangeEvent_Mapping class is a note from the development team instead of a description text.

Clause 8.4.12.4 (Control Nodes), under the Join and Fork headings says:

validateJoinNodeIncomingSuccessions constraint requires that all incoming Successions to a JoinNode have source multiplicity 1..1.

validateForkNodeOutgoingSuccessions requires that all outgoing Successions from a ForkNode have target multiplicity 1..1.

but the validation rules are missing from 8.3.16.11 (JoinNode) and 8.3.16.8 (ForkNode), respectively.

The title of 8.3.16.18 is WhileLoopsActionusage, with plural "Loops" and lower case "u", but in Figure 28 (Structured Control Actions) these are singular and capitalized, respectively.

In 8.3.16.10 (IfActionUsage), the OCL for checkIfActionUsageSpecialization refers to specifiesFromLibrary instead of specializesFromLibrary.

In 8.3.17.9 (TransitionUsage), the text for checkTransitionUsageSourceBindingConnector requires binding of the first input parameter

A TransitionUsage must have an ownedMember that is a BindingConnector between its source and its first input parameter (which redefines Actions::TransitionAction::transitionLinkSource).

while the OCL gives it as binding the second parameter

ownedMember->selectByKind(BindingConnector)->exists(b |
b.relatedFeatures->includes(source) and
b.relatedFeatures->includes(inputParameter(2)))

The body OCL for the namingFeature operation of ConstraintUsage references ownedFeatureMembership. This should instead be owningFeatureMembership.

The OCL for the constraints validateStateDefinitionIsParallelGeneralization and validateStateUsageIsParallelGeneralization both use ownedGeneralization (which doesn't exist) instead of ownedSpecialization.

The validateStateDefinitionIsParallelGeneralization and validateStateUsageIsParallelGeneralization prohibit parallel state definitions and usages from owning specializations of non-parallel state definitions and usages (and vice versa). However, this would prevent even, e.g., an empty non-parallel state definition from having a usage that was parallel, for example:

state def S;
state s : S parallel {  // validation error!
    state s1;
    state s2;
}

Further, it is also a validation error for a parallel state definition to explicitly specialized the base state definition StateAction (which is not parallel), even though an implicit specialization is not checked:

state def S1 parallel { } // legal, implicitly specializes StateAction
state def S2 :> States::StateAction parallel { } // validation error!

For consistency, it would seem that, at least, a parallel state definition or usage should be able to explicitly specialize a non-parallel one. But perhaps the constraints are really not semantically necessary at all.

The OCL for the constraint validateOccurrenceUsageIndividualDefinition is

occurrenceDefinition->select(isIndividual).size() <= 1

However, the type of OccurrenceUsage::occurrenceDefinition is actually Class, not OccurrenceDefinition, but the property isIndividual is only defined on OccurrenceDefinition.

The constraint validateUsageOwningType constrains the owningType of a Usage to be a Definition or Usage. However, this is two restrictive, because it prevents, e.g., a Usage from being declared within a body expression (as used with collect, select, etc.), which is a KerML Expression.

The constraints validateDefinitionNonVariationMembership and validateUsageNonVariationMembership check that a non-variation Definition or Usage owns no VariantMemberships. However, validateVariantMembershipOwningNamespace already checks that the membershipOwningNamespace of a VariantMembership is a variation, so the other constraints are redundant.

The constraints validateDefinitionVariationMembership and validationUsageVariationMembership require that all the owned members of a variation definition or usage be variant members. This is too strong:

• It disallows any variation Usage from having a Multiplicity, because that is a non-variant owned member of the Usage.
• It disallows a variation PortDefinition from having a required ConjugatedPortDefinition, because that is a non-variant owned member of the definition.

The constraint validateFramedConcernUsageConstraintKind is owned by FramedConcernMembership, not FramedConcernUsage (which doesn't exist). Therefore, the constraint should be named validateFramedConcernMembershipConstraintKind.

In example "Documentation Compartment", the documentation keyword should read doc

The properties RequirementUsage::subjectParameter and CaseUsage::subjectParameter in the abstract syntax SysML.xmi currently subset Behavior::parameter. However, neither RequirementUsage nor CaseUsage specialize Behavior. Rather they (indirectly) specialize Step, so the subjectParameter properties should be subsetting Step::parameter rather than Behavior::parameter.

(Note that this error is not apparent in the specification document, because, in the annotation for subsetting, the subsetted parameter is shown without qualification – e.g., just parameter, not Behavior::parameter.)

The arguments for specializesFromLibrary are sometimes single quoted and sometimes double quoted. Search on specializesFromLibrary(' and specializesFromLibrary(" to find them.

In example "Message" the arrow head should be moved to the end of the line, and should be adorned "message of item1:Item1".

In example "Connection" (1) remove circumflex on end1 and end2, since they are (implicitly) redefinitions of the ends from the connection definition, not inherited features.

Replace nested reference usage notation with dotted outline notation. Add BNF production for this notation.
Reference usage notation is used in interconnection diagrams, and potentially action flow diagram. The solution is to add explicit production for dotted usages of parts, constraints, and requirements references and include those production in interconnection diagrams. Create productions of action usage references and add them to action flow.

In example "Part with Graphical Compartment with perform actions and flows between them." add «perform action» to both action2 and action3.

In example "Part with Ports" remove "Nested" from NestedPortDef0.

In examples "Timeslices Compartment" and "Snapshots Compartment" remove state state1 feature, since it is confusing, and potentially incorrect.

Remove nested features (textual) notation from compartments in graphical symbols in all Representative Notation tables where they occur. This capability was discarded.

Simplify examples "Timeslices Compartment" and "Snapshots Compartment" by putting the compartments into a «part» context, and add e.g. phase1 and phase2 timeslices, and e.g. snapshot1 and snapshot2.

In example "Occurrences Compartment" add abstract occurrence feature for completeness.

In example "Attributes Compartment" textual notation should use nonunique instead of unique.

In example "Relationships Compartment" add textual notation that matches the graphical notation. Also "connect part3" in second symbol should be removed.

In example "Variant Membership" the variants should be defined by Part1a and Part1b respectively. Currently they are both defined by Part1.

Example "Package with imported packages (nested packages)" should have «private» enclosed by guillemets

Example "Usage Definition" should be labeled "Part defined by Part Definition"

The nesting parameter symbol productions (for actions) must have rounded corners, since they are (parameter) usages.

A succession relationship on an action flow should be a solid line with an open arrow head. In 7.16.1 in example "Accept and Send Action Flow". Check for other locations.

Table 19, Requirement, compartment for require constraints:

Typo in compartment headline should be "require constraints" => "requirre"

Clause 7.13.3 (Bindings as Usages) says

The end features of a binding always have multiplicity [1..1].

and Clause 8.3.17.9 (TransitionUsage) includes a constraint requiring a (1 to 1) binding between its succession and transitionLink:

checkTransitionUsageSuccessionBindingConnector
A TransitionUsage must have an ownedMember that is a BindingConnector between its succession and the
inherited Feature TransitionPerformances::TransitionPerformance::transitionLink.
ownedMember->selectByKind(BindingConnector)->exists(b |
b.relatedFeatures->includes(succession) and
b.relatedFeatures->includes(resolveGlobal(
'TransitionPerformances::TransitionPerformance::transitionLink')))

with similar text in 8.4.13.3 (Transition Usages). A succession will typically have fewer values than its transition usage, because the succession won't be traversed for every value (occurrence) of its source feature, while its transition usage will have the same number of values as the source feature, conflicting with the 1-1 end multiplicities. Compare to the modeling pattern in KerML Clause 9.2.10.1 (Transition Performances Overview), excerpted in KERML-157.

In (the second) example "Message" the event details should be removed from textual notation. The message becomes message msg1 from a1 to a2 in textual notation.

There are a number of cases in which derived properties require that a referenced feature by of a certain metaclass. For example, the EventOccurrenceUsage::eventOccurrence property is derived as the referencedFeature of the ownedReferenceSubsetting EventOccurrenceUsage (if it has one), but the property is typed as an OccurrenceUsage, so the referencedFeature must be an OccurrenceUsage. This is enforced by the validateEventOccurrenceUsageReference constraint.

Unfortunately, this does not take feature chaining into account. If the referencedFeature has a feature chain, it will be parsed as a plain Feature, not an OccurrenceUsage. However, the last Feature in the chain should be an OccurrenceUsage, and this OccurrenceUsage is what should be the eventOccurrence of the EventOccurrenceUsage, and what is check by validateEventOccurrenceUsageReference.

There are similar problems with at least the "reference" derivation and validation constraints for all the subtypes of EventOccurrenceUsage, and perhaps in other cases, too.

In examples "Individual Occurrence", "Timeslice", "Snapshot", add attribute to «individual» «occurrence» and redefine the attribute with value in «timeslice» and «snapshot».

The SysML v1 to v2 transformation does not map ActivityParameterNode, but only the references Parameter. The mapping of ActivityEdge must map the ends of the edge, which are connected to an ActivityParameterNode to the target element of the mapping of the Parameter.

Example "Package with imported packages (nested packages)" should use dotted instead of dashed outline

The representative notation example "Package with members compartment" shows the members compartment which is the default compartment and does not require a compartment label. Change members compartment label to the requirements compartment label and adjust the package content and textual notation accordingly, i.e. with requirement elements.

Add feature modifiers (e.g. ordered for [1..*] timestamps) to "Portion Membership" examples in representative notation tables for Occurrences.

Add feature modifiers (e.g. ordered, nonunique) to "Feature Membership" examples in representative notation tables for Definitions and Usage.

Add example package with filter in 7.5.1. The filter should be one of the filters defined in 9.2.19.2.4. Good choice is filter for Requirement.

Add import qualifier text (* or **) to upper right corner of imported Package

Add representative notation for causation (9.5.2.1) and requirements derivation (9.6.2.1) including n-arys. This (and other representative notation examples for domain library models) should probably go into the respective 9.x Overview subclauses, rather than in Clause 7.

In the param-t production the nesting parameter pdv is missing an optional nested param-t* element.

Add graphical notation to represent binding between action inputs and outputs and directed features on ports.

Graphical notation is missing support for adornments on ends of ConnectionDefinitions, such as ordered, nonunique, readonly, subsets, and redefines. This is needed for information modeling and compatibility with UML and SysML v1. In UML (and SysML v1) these adornments are called 'property modifiers'. Analogously, in KerML and SysML v2 the term 'feature modifiers' would seem appropriate.

Clarify that the identifier for the metadata declaration is the metadata definition name.

Add support for defining a metadata definition using the normal definition symbol (e.g., key word metadata def with metadata def name in name compartment). Separate compartment for attribute declarations. Add compartment redefined the annotated elements so they are constrained to be of a certain metaclass. (Note that MetadataDefinition is a kind of ItemDefinition but MetadataFeature (and therefore MetadataUsage) is a kind of AnnotatingElement.)