The metadata in the Document Components ontology is also dated and should be updated for adding to the Commons Ontology Library (per Clause 0 of the SBRM revised submission - the task force assumes that this will be done and published in Commons 1.4).

Summary

The Collections ontology gives Commons a practical core for parthood: a transitive hasPart, a direct-part property for tree views, and membership kept separate from parthood. A review of the ontology as of main (commit 655fa9c) found several internal inconsistencies. Its coverage is also thin compared with the part-whole relations in OntoUML, which is on track to become an OMG specification. This issue proposes fixes for the inconsistencies and a small set of additions that would let Commons map cleanly to OntoUML.

Current design

Collections defines two property families:

Other modules build on these:

• cmns-loc:hasSubregion and cmns-org:hasSubUnit are sub-properties of hasPart.
• cmns-rlcmp:Composition uses hasConstituent.
• cmns-cds:CodeSet and cmns-org:Organization use hasMember.
• cmns-strcol:List and cmns-strcol:ChronologicallyOrderedCollection use hasConstituent.

The split between the two families comes from an OWL 2 DL rule: cardinality restrictions are not allowed on transitive properties, so hasPart cannot be a sub-property of comprises. Even so, the note on comprises says the two "should be considered" disjoint. That presents a technical constraint as a difference in meaning. hasConstituent is defined for substances, and a portion of a substance counts as a part in nearly every account of mereology.

Problems found

1. The Constituent class contradicts hasConstituent. StructuredCollections gives cmns-col:Constituent the synonym "element" and the note "an object constituting part of a set", which describes a member. But hasConstituent is disjoint with hasMember and is meant for constituents that are not discrete elements. List and ChronologicallyOrderedCollection then use hasConstituent for their items, which are discrete and indexed. Under the current definitions, those items should use hasMember.
2. The Collection usage note recommends hasPart for collection contents. Because hasPart is transitive, the parts of a member would be inferred to be parts of the collection. Membership should be non-transitive, as OntoUML memberOf is. The usage note on Constituent has the same problem with isPartOf.
3. The change note is stale. The Collections change note for COMMONS-12 says properties were added "that allow for taxonomic parthood". No such property exists. The note may be referring to hasDirectPart.
4. Proper vs. improper parthood is not stated. The hasPart definition, taken from the Stanford Encyclopedia of Philosophy, does not say whether a thing is part of itself. OWL 2 DL cannot declare a transitive property irreflexive, so the definition text has to settle it. hasDirectPart is a simple property (it has no transitive sub-properties), so it can legally be declared asymmetric and irreflexive and used in cardinality restrictions.
5. The Organization restriction is too broad. Organization is a subclass of (hasPart only Organization), so no building, system or document can be stated as part of an organization. A restriction on hasSubUnit would capture the intent.
6. The hasMember domain is stated only in a note. The note says the domain "should be some sort of collection, aggregate, or group", but no axiom says so.
7. hasConstituent is overloaded. It is used for portions of substances (its definition), for ingredients in a Composition, and for list items (see 1). OntoUML treats these as three different relations.

Comparison with OntoUML

OntoUML, which is based on the Unified Foundational Ontology (UFO), has no single generic part-of. Modelers choose among four part-whole relation types, each with defined transitivity, and can qualify a relation with metaproperties. The table below maps Commons onto those types. It is based on OntoUML 2 as currently published, so the RTF should check it against the OMG submission text.

OntoUML models are usually transformed to OWL via gUFO, which provides isComponentOf, isCollectionMemberOf and isSubCollectionOf. If the additions above are adopted, those are natural mapping targets.

Proposed resolution

1. Fix the Constituent / hasConstituent contradiction. Either change List and ChronologicallyOrderedCollection to use hasMember, or redefine hasConstituent and drop its disjointness with hasMember.
2. Change the Collection and Constituent usage notes to recommend hasMember / isMemberOf for collection contents.
3. Correct the COMMONS-12 change note.
4. State in the hasPart definition whether parthood is reflexive. Declare hasDirectPart asymmetric and irreflexive.
5. Replace the Organization restriction on hasPart with one on hasSubUnit.
6. Decide whether to axiomatise the domain of hasMember.
7. Add hasSubCollection / isSubCollectionOf (transitive, sub-property of hasPart) and hasComponent / isComponentOf (sub-property of hasDirectPart).
8. Add explanatory notes linking the Commons properties to the corresponding OntoUML relation types.
9. For discussion: make hasDirectPart a sub-property of comprises as well as of hasPart. comprises would stay simple, so cardinality restrictions on it remain legal, and the two hierarchies would join at the direct level. This conflicts with the current "should be considered disjoint" note on comprises, which would need revising.

Summary

Parthood is a foundational subject and we're lacking even partially-complete coverage in OMG to form the basis of other specifications or customer ontologies.
Mereology has a lot of potential aspects, only a minority of which are related to Collections, which is where the support we have is squirreled away (and hard to find). Even what we currently have there has little to do with collections: organizational sub-units, geographic subregions, and components of compositions.
This issue proposes moving the whole-part relations into a small, separate Commons ontology (working name Parthood) that Collections and other modules import. The new module would also give Commons a home for alignment with the part-whole relations in OntoUML, which is on track to become an OMG specification.

This issue is related to COMMONS-26, which fixes inconsistencies in the current Collections parthood and membership properties. Those fixes should not wait for this one.

Motivation

1. Parthood is a general topic. hasPart / isPartOf sit in Collections because of the ontology's origins in LCC, not because they relate to collections. cmns-org:hasSubUnit and cmns-loc:hasSubregion are sub-properties of hasPart and have no connection to collections.
2. Defining parthood and membership together has caused confusion. Several problems raised in COMMONS-XX come from this: the Constituent class contradicts hasConstituent, the Collection usage note recommends the transitive hasPart for collection contents, and hasConstituent is used for three different relations. A separate module puts the distinction into the structure, not just the usage notes.
3. OntoUML alignment needs a home. OntoUML distinguishes componentOf, memberOf, subCollectionOf and subQuantityOf, and qualifies part-whole relations with metaproperties (essential, inseparable, immutable part, immutable whole, shareable). Only memberOf belongs with collections; the rest belong in a parthood module.
4. Modeling guidance for OWL belongs in one place. Transitive properties cannot carry cardinality restrictions or be declared irreflexive or asymmetric in OWL 2 DL. Commons works around this by pairing a transitive property with a simple direct-part property. That pattern should be documented once, with the properties it applies to.

Scope

The module covers parthood relations that are useful in business, regulatory and technical models, mapped to OntoUML part-whole relations where possible. It is not a general theory of mereology: overlap, mereological sums, mereotopology and temporally indexed parthood are out of scope.

Proposed contents

The module would also include:

• annotation properties, or usage guidance, for the OntoUML part-whole metaproperties, which OWL cannot express directly
• usage notes on weak supplementation (a whole has at least two parts) and on the transitive / direct property pattern
• explanatory notes mapping each property to its OntoUML relation type

Changes to other modules

• Collections imports Parthood and keeps comprises, isIncludedIn, hasMember, isMemberOf, Arrangement and the structured-collection classes. It adds hasSubCollection / isSubCollectionOf as a sub-property of hasPart (maps to OntoUML subCollectionOf). hasConstituent is either redefined to mean items of a collection or folded into hasMember, depending on the outcome of COMMONS-XX.
• Organizations and Locations point hasSubUnit and hasSubregion (and their inverses) at the Parthood properties.
• RolesAndCompositions reviews whether Composition should use hasComponent, hasPortion, or both, and adds a note that composition is distinct from parthood.

Migration

cmns-col:hasPart, cmns-col:isPartOf, cmns-col:hasDirectPart and cmns-col:isDirectPartOf are used by FIBO, LCC and other downstream ontologies. To avoid breaking them:

1. Keep the existing IRIs in Collections, declare each one owl:equivalentProperty to its replacement in Parthood, and mark it deprecated.
2. Keep the deprecated IRIs for at least two Commons revisions before removing them.
3. Coordinate the timing with the FIBO and LCC teams.

Open questions

1. Module name: Parthood, PartsAndWholes, or another name.
2. Should the module define Whole and Part classes, or only properties?
3. Should hasDirectPart also be a sub-property of comprises, joining the two hierarchies at the direct level? (Raised in COMMONS-XX.)
4. Name for the portion / sub-quantity property.
5. Whether to declare the OntoUML mappings formally (for example against gUFO) or only in explanatory notes.

Certain kinds of records, such as financial records, are not limited to documents. They are containers for various things but are not necessarily documents.

Both the retail and manufacturing domain task forces have expressed a need for something they can use as the basis for building out the notion of a product. The concept of a service is now part of the organizations ontology, but product remains a gap. High level concepts of stock keeping unit and GTIN are also needed for supply chain and other use cases that are shared across task forces.

The resolution of this issue depends on the resolution of COMMONS14-17 due to the need for common updates to the informative about commons vocabulary.

A number of OMG and external processes have requested us to add an address ontology to Commons, including manufacturing (CASCaRA), retail (RIO), systems engineering (SE DSIG, for various applications) and EDMA for FIBO and other external community ontology efforts.

The original address ontology from FIBO is a good start for this. It reflects definitions from the Global LEI Foundation (GLEIF) for corporate addresses as well as additional detail from USPS Publication 28, which is used not only by the US Postal Service but by many logistics companies world-wide. For a number of years there was no ISO standard for addresses, and the recent addition of such a standard is skewed towards the EU (heavily). US regulatory agencies in financial services have mandated the use of USPS Pub 28, which is why that is the primary source for FIBO. The new Commons ontology should reflect USPS Pub 28 but also be compatible with the recent ISO standard.

There is a gap in the quantities and units ontology whereby we cannot represent counts of things, which do not necessarily have units, nor can we properly represent ratio values, which may involve scalar quantity values that do not have units. There is also a challenge in representing ratio values more generally, since there is no numeric value representing the ratio on the class.

SysML v2 defines scalar quantities in terms of tensor and vector quantities, but these are missing in the Commons quantities and units ontology. They are needed to generate the library corresponding to the SysML quantities and units library

The link, https://www.nationalgeographic.org/encyclopedia/region/, no longer resolves. This should be replaced with another source that resolves properly.

Note that the metadata in the specification is missing this detail, so if a better resource is not found, only the machine readable files need to be modified.

Use of either skos:editorialNote or cmns-av:explanatoryNote is ok, but the RIO team would like to have an additional modeling note that specifically tells other ontologists / taxonomists why certain modeling decisions were made.

Currently, 'index value' is a subclass of aspect, but it points to something rather than characterizing something. It should be a subclass of designation rather than aspect.

Currently, a geopolitical entity is a subclass of geographic region. But, a geopolitical entity can span regions, and in a handful of cases may not be associated with well-defined borders. A geopolitical entity would be better defined as a political entity associated with a geographic region, and loosen the relationship between the two concepts.

The definitions in Collections are terse or drawn from diverse sources, and the notes focus on technical aspects (such as transitivity) that don't help a modeler decide which to use.
hasMember definition is overly terse, whereas hasPart is almost absurdly long and littered with disjunctions making it all-inclusive of anything.

in FIBO for example hasPart is used to link from a PooledFund to its FundUnits, and a BondPool to its Bonds. And from a Judiciary to its Courts.
But on the other hand hasMember is used to link a Program to its Projects and an InstrumentPool to its FinancialIstruments.

Clearly there is some understanding of the distinction being deployed in FIBO, especially related to Pools, that is not clear in the Commons definitions. Especially because BondPool subclasses DebtPool which subclasses InstrumentPool which has a hasMember restriction, yet hasPart is used.
Also it's unclear why hasPart has no relation to comprises.
Generally I think there's too much in authors' heads and not enough written - which is essential for successful and consistent usage in ontologies, data and queries.

Definitions follow:
hasMember: includes, as a discrete element. Note that the domain of hasMember should be some sort of collection, aggregate, or group. In the Financial Industry Business Ontology (FIBO), hasMember is used in the case of parties (people and organizations), whereas comprises can have anything in its range.

hasPart: indicates any portion of something, regardless of whether the portion itself is attached to the remainder or detached; cognitively salient or arbitrarily demarcated; self-connected or disconnected; homogeneous or gerrymandered; material or immaterial; extended or unextended; spatial or temporal

For generated ontologies such as BACM, and applications that need access to the blank nodes in an ontology, it is useful to have a UUID for every node, particularly blank nodes, which could be handled as an annotation. For alignment with XMI metamodels it may be quite useful.

This request came from BMI. We could add it to either (1) the annotation vocabulary, or (2) one of the identifier ontologies in Commons

For visibility outside OMG I think we should be registering all our ontologies which I think may require a few extra items of metadata as here https://lov.linkeddata.es/Recommendations_Vocabulary_Design.pdf such as Dublin Core terms title and description (we have label and abstract), (date) issued and modified, and for elements, rdfs:comment (we have the more specific skos:definition). I think most of these could be added via automated script (e.g. Each skos:definition also becomes a rdfs:comment).

expressesTheMagnitudeOf
Definition: indicates the subject or topic of something, such as
a document
Range: ScalarQuantity

I'm pretty sure the definition is wrong.
And the range seems wrong too.

We've said that hasMember is distinct from hasConstituent, but the actual definitions are not necessarily obviously different to users. The definition of hasConstituent changed after the original ontology was submitted, and the notion of Constituent as a class could be used to support either members or constituents, even though the properties in question are disjoint.

It is likely that we need to find a different "word" or "phrase" to describe elements of a composite that are not necessarily distinguishable from one another, and revise the ontology accordingly.