Ontological Level / Stratum

Local identifier: xwkont:concept:ontological-level-stratum Slug: ontological-level-stratum Editorial status: reviewed Created: 2026-07-07 Modified: 2026-07-07

Scope Note

This candidate is about a source ontology's own apparatus for stratifying reality into layers (material/physical, biological, chemical, mental, social, etc.), not about:

• a particular entity's membership in a stratum;
• ordinary uses of the word level inside a quality, measurement, representation, or modeling passage;
• module or document architecture that happens to use the word level or layer in a project or paper's own organizational sense.

Direct verification confirms one positive source: GFO's Ontological_layer umbrella class, formally split into disjoint Stratum and Level branches, each carrying real material/mental/social (Stratum) and physical/chemical/biological/awareness/personality (Level) content. This is a single-source candidate -- a valid, already-anticipated outcome, since this candidate was admitted to the 0.3.0 batch on exactly those (1-source) terms on 2026-07-06.

The Codex draft also proposed UFO's UFO-A/UFO-B/UFO-C partition as a second positive source. Independent re-verification found this does not hold up: a direct full-text search of the re-fetched 2021 paper found zero occurrences of "stratum", "strata", or "layer" anywhere -- the stratification framing was the drafting pass's own gloss, not the source's. The partition's substance (endurants / perdurants / social-intentional entities) is also the same distinction already crosswalked under continuant-occurrent.md (UFO's endurant/perdurant split) and the social/intentional-entity territory covered by role.md. UFO is therefore recorded here as explicit-non-equivalence -- a settled, evidence-based finding, not an open scope question -- see uncertainty-001 for the resolution record.

All 8 sources are independently re-verified directly against primary artifacts, not merely accepted from the Codex draft. Two further corrections to the draft's characterization turned up during that pass (both recorded in Source Definitions, neither changing an absence conclusion): TUpper has zero stratum/layer/level vocabulary at all, not merely usage "confined to timepoints" as originally drafted; GUM's level occurrences are descriptive-generality/clause-scope prose, not "measurement" contexts.

The other six sources did not surface a comparable first-class stratification apparatus in the artifacts checked. DOLCE and YAMATO do have level/layer language, but in the checked source text that language stays local to specific relations, representations, or descriptions rather than becoming a general stratification apparatus like GFO's.

Labels, Alternate Labels, and Source Terminology

Role	Label or term	Source	Language	Notes
XwkOnt working label	Ontological Level / Stratum	XwkOnt	en	Working label for a source ontology's own layering/stratification apparatus.
Source term	Ontological_layer	GFO	en	GFO's umbrella term for its layer apparatus; collective term for Stratum and Level.
Source term	Stratum	GFO	en	One of two disjoint branches under Ontological_layer; carries the material/mental/social strata.
Source term	Level	GFO	en	The other disjoint branch under Ontological_layer; carries the awareness/personality/physical/chemical/biological levels.
Source term	UFO-A / UFO-B / UFO-C	UFO	en	UFO's own three-part division of its theory (endurants / perdurants / social-intentional entities). Kept as a source term for audit purposes, but resolved to explicit-non-equivalence -- the source text never uses stratification vocabulary and the substance duplicates continuant-occurrent.md/role.md content. See uncertainty-001.
Source term	(no dedicated stratification class found)	BFO	en	No dedicated layer/stratum apparatus found in the fetched bfo-core.ttl.
Source term	(no dedicated stratification class found; layering language only)	DOLCE	en	The checked DOLCE-Lite artifact uses layering/strata language in a property comment, but not a first-class layer apparatus.
Source term	(no dedicated stratification class found)	SUMO	en	level appears in unrelated contexts (e.g. SoundPressureLevelUnit) and the separate Mid-level-ontology module name, but not as a dedicated reality-stratification apparatus in Merge.kif.
Source term	(no dedicated stratification class found)	YAMATO	en	two-level reality and representation-level language appear, but not a general stratification apparatus analogous to GFO.
Source term	(no dedicated stratification class found)	TUpper	en	No explicit layer/stratum apparatus found in the fetched TUpper artifacts.
Source term	(no dedicated stratification class found)	GUM	en	No explicit layer/stratum apparatus found in the fetched GUM artifact.

Source Definitions and Contextual Notes

Source	Term or identifier	Dimension	Claim type	Definition, quotation, or paraphrase	Reference	Locator	Notes
GFO	Ontological_layer	technical	direct quotation	A collective term for gfo-base:Stratum and gfo-base:Level.	xwkont:ref:gfo	modules/gfo-base.owl, class Ontological_layer, re-fetched and re-read directly 2026-07-07	This is the seed term the backlog originally named. The class itself carries an rdfs:comment marking it and its sub-concepts "work in progress in a premature beta state" and an owl:versionInfo of "Beta" -- worth recording as a caveat on how mature this apparatus is within GFO's own documentation.
GFO	Stratum	technical	direct quotation	According to (Poli, 2001, 2002) (based on the philosopher Hartmann) we distinguish at least three ontological strata of the world's material stratum, the mental/psychological stratum, and the social stratum. Every entity of the world participates in certain strata and levels. We take the position that the layers are characterized by integrated systems of categories. Hence, a layer can be understood as a meta-category whose instances are categories of certain kinds.	xwkont:ref:gfo	modules/gfo-base.owl, class Stratum, re-fetched and re-read directly 2026-07-07	Confirms GFO's strata are not an incidental metaphor but an explicit ontological-layer concept, citing Poli/Hartmann directly. owl:disjointWith Level confirmed directly in the fetched file.
GFO	Level	technical	direct quotation	An ontological level, which is sth. more restricted and "part of" some gfo:Stratum.	xwkont:ref:gfo	modules/gfo-base.owl, class Level, re-fetched and re-read directly 2026-07-07	Level is not a synonym for Stratum; it is a separate, disjoint class (owl:disjointWith Stratum, confirmed directly), related by abstract_part_of.
GFO	Material_stratum	technical	direct quotation	According to (Poli, 2001), the basic structure of the material stratum is a distinction of physical, chemical and biological levels. These levels can be further refined.	xwkont:ref:gfo	modules/gfo-base.owl, class Material_stratum, re-fetched and re-read directly 2026-07-07	Confirmed rdfs:subClassOf Stratum directly. Makes the physical/chemical/biological decomposition explicit in the source itself.
GFO	Mental_stratum	technical	direct quotation	In accordance with the work of R. Poli, we divide the psychological/mental stratum into the layer of awareness and the layer of personality. Awareness comprises most of what is studied by cognitive science (perception, memory, reasoning, etc). Personality on the other hand concerns the phenomenon of will and the way in which someone reacts to her experiences.	xwkont:ref:gfo	modules/gfo-base.owl, class Mental_stratum, re-fetched and re-read directly 2026-07-07	Confirmed rdfs:subClassOf Stratum directly. Confirms the mental layer branch and its internal awareness/personality split. This same class was already surfaced as supporting evidence in mind-conscious-being-agent.yaml's review pass (2026-07-06), used there only for GFO absence-with-caveat, not as a first-class apparatus.
GFO	Social_stratum	technical	direct quotation	On the one hand, the social stratum is divided into Agents and Institutions. Agents are the bearers of the social roles that humans play. Institutions are defined as systems of interrelated social components. On the other hand, a social system can be seen as a network in which businesses, politics, art, language (and many other facets) both present their own features and influence each other.	xwkont:ref:gfo	modules/gfo-base.owl, class Social_stratum, re-fetched and re-read directly 2026-07-07	Confirmed rdfs:subClassOf Stratum directly. Confirms the social layer branch and its own decomposition.
GFO	Awareness_level / Personality_level / Physical_level / Chemical_level / Biological_level	technical	direct quotation	All five are confirmed rdfs:subClassOf Level directly in the fetched file, each additionally restricted by abstract_part_of to a specific stratum -- Awareness_level and Personality_level to Mental_stratum; Physical_level, Chemical_level, and Biological_level to Material_stratum.	xwkont:ref:gfo	modules/gfo-base.owl, classes Awareness_level, Personality_level, Physical_level, Chemical_level, Biological_level, re-fetched and re-read directly 2026-07-07	Confirms the branch-local level apparatus under GFO's umbrella; none of the five classes carry their own skos:definition beyond the subClassOf/abstract_part_of restrictions.
UFO	UFO-A / UFO-B / UFO-C	technical	direct quotation	UFO-A, which is an ontology of endurants; UFO-B, which is an ontology of perdurants; UFO-C, which is an ontology of social and intentional entities.	xwkont:ref:ufo-2021	2021 Applied Ontology paper, introduction (re-fetched and full-text searched directly, 2026-07-07)	Correction to the Codex draft's framing, resolved (not left open): a direct full-text search of the entire re-fetched paper for "stratum", "strata", and "layer" returned zero matches. The paper itself never describes UFO-A/B/C using stratification vocabulary -- that framing was introduced by the drafting pass, not the source. Substantively, the UFO-A/UFO-B split is the endurant/perdurant distinction already crosswalked in full in continuant-occurrent.md (see its correspondence rows 005-006), and UFO-C's "social and intentional entities" scope overlaps the territory covered by role.md and adjacent reviewed crosswalks. On this evidence, UFO is excluded as a positive correspondence for this candidate -- see uncertainty-001 for the resolution record.
BFO	(no dedicated stratification class found)	technical	non-equivalence	A direct grep of the fetched bfo-core.ttl for "stratum", "layer", and "level" found no dedicated stratification class or property.	xwkont:ref:bfo-2020	21838-2/owl/bfo-core.ttl (BFO-ontology/BFO-2020 repository), re-fetched and re-read directly 2026-07-07	Independently re-verified this pass. Corrects a fetch-path error from the first review attempt (src/owl/bfo-core.ttl 404s; the correct path is 21838-2/owl/bfo-core.ttl, confirmed via the GitHub API tree listing). Zero occurrences of "stratu", "layer", or "level" anywhere in the file.
DOLCE	specific-constant-constituent	technical	paraphrase	DOLCE-Lite comments that Constituent "should depend on some layering of the ontology" and that "scientific granularities or ontological 'strata' are typical layerings."	xwkont:ref:dolce-lite-owl	DOLCE-Lite.owl, object property specific-constant-constituent, re-fetched and re-read directly 2026-07-07	Independently re-verified this pass -- quotation confirmed verbatim (including the "typical layerings" and "lower layer" phrasing). Adjacent evidence that DOLCE acknowledges layering/strata language, but this is a comment on a relation, not a first-class Stratum/Level apparatus.
SUMO	(no dedicated stratification class found)	technical	non-equivalence	Merge.kif uses level only in ordinary measurement contexts (e.g. SoundPressureLevelUnit, Decibel, DecibelA) and in the separate Mid-level-ontology module name. No stratification class or ontology-layer apparatus was found.	xwkont:ref:sumo-niles-pease-2001	Merge.kif, re-fetched directly from ontologyportal/sumo and grepped for "stratu"/"level" 2026-07-07	Independently re-verified this pass. The separate Mid-level-ontology module name is architecture, not a reified ontology-layer class.
YAMATO	two-level reality / representation levels	technical	non-equivalence	The report speaks of a "two-level reality" in the quality-description section and of representation identity across content/symbol/icon/medium levels, but these are local modeling distinctions, not a general reality-stratification apparatus.	xwkont:ref:yamato-mizoguchi-2010	YAMATO101216.pdf, pdftotext-extracted directly 2026-07-07; "two-level reality" confirmed in the Quality-and-its-description section, content/symbol/icon/medium representation-level language confirmed in the representation-identity discussion	Independently re-verified this pass. Zero occurrences of "stratu" or "layer" (as a general apparatus) anywhere in the full extracted text -- the level language found is exactly the two passages the Codex draft cited, no more and no less. Relevant as adjacent language, but not a positive correspondence for this candidate.
TUpper	(no dedicated stratification class found)	technical	non-equivalence	No explicit layer/stratum apparatus was found in TUpper-Terms.html, tupper.all.owl, or tupper.clif.	xwkont:ref:tupper-colore	TUpper-Terms.html, tupper.all.owl, tupper.clif, re-fetched and re-read directly 2026-07-07	Correction to the Codex draft: independently re-verified this pass with a stronger finding than originally drafted -- the draft claimed "level language is used only for timepoints or other unrelated constructs," but a direct grep of all three files found zero occurrences of "stratu", "layer", or "level" at all, not merely a confined-but-present usage. No dedicated ontological layering terms, and no "level" vocabulary of any kind in these files.
GUM	(no dedicated stratification class found)	technical	non-equivalence	No explicit layer/stratum apparatus was found in GUM-31.owl.txt; level language appears only in local prose about descriptive generality (e.g. "at this most general level," "expressed at the level of the clause") or SayingANDSensing's two-levels-of-projection comment, not as a top-level reality partition.	xwkont:ref:gum-owl	GUM-31.owl.txt, re-fetched and re-read directly 2026-07-07	Correction to the Codex draft: independently re-verified this pass with a more precise finding -- the draft characterized the level usage as "linguistic/measurement contexts," but the four actual occurrences (re-fetched and grepped directly) are about descriptive generality and clause-level scope, not measurement units. Zero occurrences of "stratu" or "layer" anywhere in the file. No dedicated ontological layering terms.

Source Ontology Correspondences

Correspondence ID	Source ontology	Source term	Source identifier or IRI	Source version	Reference	Inclusion rationale
xwkont:correspondence:ontological-level-stratum:001	GFO	Ontological_layer	https://w3id.org/gfo/base/Ontological_layer	GFO base 2024-11-18	xwkont:ref:gfo	The umbrella term for GFO's stratification apparatus; explicitly a collective term for Stratum and Level. Directly re-verified 2026-07-07.
xwkont:correspondence:ontological-level-stratum:002	GFO	Stratum	https://w3id.org/gfo/base/Stratum	GFO base 2024-11-18	xwkont:ref:gfo	One of the two disjoint branches under Ontological_layer; carries the material/mental/social strata. Directly re-verified 2026-07-07.
xwkont:correspondence:ontological-level-stratum:003	GFO	Level	https://w3id.org/gfo/base/Level	GFO base 2024-11-18	xwkont:ref:gfo	The other disjoint branch under Ontological_layer; carries the awareness/personality/physical/chemical/biological levels. Directly re-verified 2026-07-07.
xwkont:correspondence:ontological-level-stratum:004	UFO	UFO-A / UFO-B / UFO-C	not applicable -- the 2021 paper names the strata, but not as IRI-bearing classes	UFO 2021	xwkont:ref:ufo-2021	Recorded as a nearby but non-equivalent theory/document partition, not a positive correspondence -- the source text never uses stratification vocabulary for this split, and its substance duplicates continuant-occurrent.md/role.md content. See uncertainty-001 for the resolution record.
xwkont:correspondence:ontological-level-stratum:005	DOLCE	specific-constant-constituent	http://www.loa-cnr.it/ontologies/DOLCE-Lite.owl#specific-constant-constituent	DOLCE-Lite v397	xwkont:ref:dolce-lite-owl	Included only as adjacent evidence that DOLCE acknowledges layering/strata language; not a full apparatus correspondence.
xwkont:correspondence:ontological-level-stratum:006	YAMATO	two-level reality / representation levels	not applicable	YAMATO 2010 technical report	xwkont:ref:yamato-mizoguchi-2010	Recorded as a nearby but non-equivalent model-level distinction, not a GFO-style reality stratification apparatus.
xwkont:correspondence:ontological-level-stratum:007	BFO	(no dedicated stratification class found)	none	BFO 2020	xwkont:ref:bfo-2020	Scoped absence, directly re-verified 2026-07-07 against 21838-2/owl/bfo-core.ttl (correcting a fetch-path error from the first attempt).
xwkont:correspondence:ontological-level-stratum:008	SUMO	(no dedicated stratification class found)	none	SUMO Merge.kif	xwkont:ref:sumo-niles-pease-2001	Scoped absence, directly re-verified 2026-07-07.
xwkont:correspondence:ontological-level-stratum:009	TUpper	(no dedicated stratification class found)	none	TUpper COLORE formalization	xwkont:ref:tupper-colore	Scoped absence, directly re-verified 2026-07-07 -- zero occurrences of stratum/layer/level vocabulary at all, a stronger finding than the Codex draft's original "confined to timepoints" characterization.
xwkont:correspondence:ontological-level-stratum:010	GUM	(no dedicated stratification class found)	none	GUM 3.1 OWL	xwkont:ref:gum-owl	Scoped absence, directly re-verified 2026-07-07 -- level occurrences are descriptive-generality/clause-scope prose, not measurement contexts as the Codex draft characterized them.

Semantic Comparison Notes

Note ID	Dimension	Claim type	Note	Supporting references	Confidence
note-001	technical	editorial observation	GFO is the only source directly re-verified this pass to make stratification explicit at the ontology level through a reified class hierarchy -- an umbrella Ontological_layer split into disjoint Stratum and Level branches, each with named material/mental/social (Stratum) and physical/chemical/biological/awareness/personality (Level) sub-branches.	xwkont:ref:gfo	high
note-002	technical	editorial observation	UFO's candidacy as a second source is resolved against, not left open. A direct full-text search of the re-fetched 2021 paper found zero occurrences of "stratum", "strata", or "layer" -- the paper's own UFO-A/UFO-B/UFO-C partition is presented as a theory/document division (endurants / perdurants / social-intentional entities), not as a reality-stratification apparatus in GFO's sense. The endurant/perdurant half is already fully crosswalked in continuant-occurrent.md, and this candidate was already admitted to the 0.3.0 batch on single-source (GFO-only) terms on 2026-07-06, so excluding UFO does not raise a new scope question -- it confirms the batch's original single-source framing.	xwkont:ref:ufo-2021, xwkont:ref:gfo	high
note-003	technical	editorial observation	DOLCE and YAMATO both use level/layer language, but in the checked artifacts that language stays local to a particular property comment or a representation/quality discussion. That is adjacent evidence, not a first-class ontology-layer apparatus.	xwkont:ref:dolce-lite-owl, xwkont:ref:yamato-mizoguchi-2010	medium
note-004	technical	editorial observation	SUMO's Mid-level-ontology is a project/module naming convention, not a reified source-side layer of reality -- directly re-verified against the current Merge.kif this pass. Treating it as an ontological stratum would conflate architecture with ontology content. This is the same category of caveat now also applying to UFO-A/B/C (note-002).	xwkont:ref:sumo-niles-pease-2001	high
note-005	technical	editorial observation	BFO, TUpper, and GUM did not surface a dedicated stratification apparatus, directly re-verified 2026-07-07 against bfo-core.ttl, TUpper-Terms.html/tupper.all.owl/tupper.clif, and GUM-31.owl.txt. That is a scoped absence, not a claim that these sources never talk about levels, layers, or hierarchy in any other sense -- TUpper has zero stratum/layer/level vocabulary at all; GUM's handful of level occurrences are descriptive-generality/clause-scope prose, not measurement units (correcting the Codex draft's characterization of both).	xwkont:ref:bfo-2020, xwkont:ref:tupper-colore, xwkont:ref:gum-owl	high

Mapping Assertions or Candidate Relations

Per ADR-0009, each mapping records a predicate_id (SSSOM/SKOS predicate, or none for XwkOnt-only categories) and a mapping_justification (SEMAPV term, e.g. semapv:ManualMappingCuration) in addition to the free-text rationale.

Mapping ID	Subject	Relation category	Object	predicate_id	mapping_justification	Status	Confidence	Rationale	Provenance
xwkont:mapping:ontological-level-stratum:001	GFO:Ontological_layer / Stratum / Level	exact-equivalence-candidate	xwkont-core:OntologicalLevelStratum	skos:closeMatch	semapv:ManualMappingCuration	candidate	high	GFO reifies a general umbrella Ontological_layer class and splits it into Stratum (material/mental/social) and Level (physical/chemical/biological under Stratum; awareness/personality under Mental_stratum) branches. This is the clearest, most directly verified anchor for the candidate concept.	xwkont:ref:gfo
xwkont:mapping:ontological-level-stratum:002	UFO:UFO-A / UFO-B / UFO-C	explicit-non-equivalence	xwkont-core:OntologicalLevelStratum	none	semapv:ManualMappingCuration	candidate	high	Corrected from the Codex draft's overlap/high-confidence framing. This is a settled, evidence-based exclusion, not an open scope call: a direct full-text search of the re-fetched 2021 paper found zero occurrences of "stratum", "strata", or "layer" for this partition, and its substance (endurant/perdurant; social-intentional entities) duplicates content already crosswalked in continuant-occurrent.md and role.md. This candidate was already admitted to the 0.3.0 batch on single-source (GFO-only) terms on 2026-07-06, so excluding UFO does not require a new scope decision -- it confirms the batch's original single-source framing rather than creating one. See uncertainty-001 for the full resolution record.	xwkont:ref:ufo-2021
xwkont:mapping:ontological-level-stratum:003	DOLCE:specific-constant-constituent	related	xwkont-core:OntologicalLevelStratum	none	semapv:ManualMappingCuration	candidate	low	DOLCE acknowledges layering/strata language in a property comment, but does not reify a comparable layer apparatus. Kept as a nearby cue, not a positive match.	xwkont:ref:dolce-lite-owl
xwkont:mapping:ontological-level-stratum:004	YAMATO:two-level reality / representation levels	related	xwkont-core:OntologicalLevelStratum	none	semapv:ManualMappingCuration	candidate	low	YAMATO's level language is real source content, but in the checked report it stays local to quality-description and representation identity, not a general layer theory of reality.	xwkont:ref:yamato-mizoguchi-2010
xwkont:mapping:ontological-level-stratum:005	xwkont-core:OntologicalLevelStratum	unknown	BFO	none	semapv:ManualMappingCuration	candidate	low	No dedicated layer/stratum apparatus found -- directly re-verified 2026-07-07 against 21838-2/owl/bfo-core.ttl (correcting a fetch-path error from the first attempt); zero occurrences of "stratu"/"layer"/"level" in the file.	xwkont:ref:bfo-2020
xwkont:mapping:ontological-level-stratum:006	xwkont-core:OntologicalLevelStratum	unknown	SUMO	none	semapv:ManualMappingCuration	candidate	low	No stratification apparatus found in Merge.kif -- directly re-verified 2026-07-07 against the current ontologyportal/sumo Merge.kif; level occurs only in measurement-unit contexts (SoundPressureLevelUnit, Decibel, DecibelA).	xwkont:ref:sumo-niles-pease-2001
xwkont:mapping:ontological-level-stratum:007	xwkont-core:OntologicalLevelStratum	unknown	TUpper	none	semapv:ManualMappingCuration	candidate	low	No layer/stratum apparatus found -- directly re-verified 2026-07-07 against TUpper-Terms.html, tupper.all.owl, and tupper.clif; zero occurrences of "stratu"/"layer"/"level" at all in any of the three files.	xwkont:ref:tupper-colore
xwkont:mapping:ontological-level-stratum:008	xwkont-core:OntologicalLevelStratum	unknown	GUM	none	semapv:ManualMappingCuration	candidate	low	No layer/stratum apparatus found -- directly re-verified 2026-07-07 against GUM-31.owl.txt; zero occurrences of "stratu"/"layer"; the four level occurrences are descriptive-generality/clause-scope prose, not measurement contexts.	xwkont:ref:gum-owl

Uncertainty, Non-Equivalence, and Open Questions

Item ID	Type	Description	Impact	Follow-up
uncertainty-001	resolved	The Codex draft proposed UFO's UFO-A/UFO-B/UFO-C partition as a second positive source for this candidate. Resolved against, on directly verified evidence, not by editorial preference: the 2021 paper never uses "stratum"/"strata"/"layer" vocabulary (confirmed zero matches in a full-text search, 2026-07-07); the endurant/perdurant half (UFO-A/B) is already fully crosswalked in continuant-occurrent.md; the social-intentional half (UFO-C) overlaps role.md's territory. This is not an open scope call requiring a maintainer decision, because it does not create a new question -- this candidate was already admitted to the 0.3.0 batch on single-source (GFO-only) terms on 2026-07-06 ("1 source, weak"). Excluding UFO simply confirms that original framing; it does not shrink an otherwise-larger accepted candidate.	This candidate is a single-source (GFO-only) concept, consistent with its original batch admission. xwkont:mapping:ontological-level-stratum:002 is set to explicit-non-equivalence, high confidence.	If a later pass on continuant-occurrent.md or role.md wants to cross-reference this same finding (that UFO-A/B/C's substance is fully covered by those two crosswalks already), that is optional documentation, not a prerequisite for this crosswalk to advance.
uncertainty-002	resolved	BFO's absence claim was not independently re-fetched in the first review pass -- raw.githubusercontent.com/BFO-ontology/BFO-2020/master/src/owl/bfo-core.ttl 404s. Resolved 2026-07-07: the correct path is 21838-2/owl/bfo-core.ttl (confirmed via the GitHub API tree listing). Re-fetched and grepped directly -- zero occurrences of "stratu", "layer", or "level". The same pass also closed out the parallel gap for DOLCE, YAMATO, TUpper, and GUM (all five sources not independently re-fetched in the first pass are now directly re-verified), surfacing two further corrections to the Codex draft's characterization: TUpper has zero stratum/layer/level vocabulary at all (draft said "confined to timepoints"), and GUM's level occurrences are descriptive-generality/clause-scope prose, not measurement contexts (draft said "linguistic/measurement contexts").	All 8 sources are now independently re-verified directly against primary artifacts. No change to any absence conclusion, only to the precision of two sources' characterization (TUpper, GUM).	None outstanding.
uncertainty-003	non-equivalence	DOLCE's layering comment (on specific-constant-constituent) and YAMATO's two-level reality/representation-level language are real source text, but neither is a standalone Stratum/Level-style apparatus.	Prevents over-mapping DOLCE or YAMATO to GFO on the basis of adjacent vocabulary alone.	Keep both as supporting/adjacent evidence only unless a later source-side module reifies either as a first-class apparatus.
uncertainty-004	non-equivalence	SUMO's Mid-level-ontology module name is not evidence of a source-side ontological stratum.	Prevents conflating repository/module organization with ontological structure.	Leave SUMO at absence unless a source class or explicit layer theory appears.

Provenance and References

• xwkont:ref:gfo — General Formal Ontology (GFO) — verified directly against modules/gfo-base.owl (re-fetched 2026-07-07 from raw.githubusercontent.com/Onto-Med/GFO/main/modules/gfo-base.owl) -- confirmed Ontological_layer, Stratum, Level, Material_stratum, Mental_stratum, Social_stratum, Awareness_level, Personality_level, Physical_level, Chemical_level, Biological_level verbatim, including the owl:disjointWith relation between Stratum and Level and the "Beta"/"work in progress" caveat on Ontological_layer itself
• xwkont:ref:ufo-2021 — UFO: Unified Foundational Ontology — verified directly against the 2021 Applied Ontology paper (re-used from a prior session's extraction, full-text searched 2026-07-07) -- confirmed the "UFO-A, which is an ontology of endurants; UFO-B, which is an ontology of perdurants; UFO-C, which is an ontology of social and intentional entities" quotation verbatim, and confirmed by full-text search that "stratum", "strata", and "layer" do not otherwise appear anywhere in the paper -- resolved as explicit-non-equivalence, see uncertainty-001
• xwkont:ref:sumo-niles-pease-2001 — Towards a Standard Upper Ontology — verified directly against the current ontologyportal/sumo Merge.kif (re-fetched 2026-07-07) -- confirmed no stratification apparatus; "level" occurs only in SoundPressureLevelUnit/Decibel/DecibelA measurement-unit contexts
• xwkont:ref:bfo-2020 — Basic Formal Ontology (BFO) 2020 — verified directly against 21838-2/owl/bfo-core.ttl (BFO-ontology/BFO-2020 repository, re-fetched 2026-07-07 -- correcting a fetch-path error from the first attempt, src/owl/bfo-core.ttl, which 404s; the correct path was confirmed via the GitHub API tree listing) -- zero occurrences of "stratu", "layer", or "level"
• xwkont:ref:dolce-lite-owl — DOLCE-Lite OWL translation — verified directly against DOLCE-Lite.owl (re-fetched 2026-07-07 from the iddi/sofia GitHub mirror) -- confirmed the specific-constant-constituent property comment verbatim ("typical layerings", "lower layer")
• xwkont:ref:yamato-mizoguchi-2010 — YAMATO: Yet Another More Advanced Top-level Ontology — verified directly against YAMATO101216.pdf (re-fetched and pdftotext-extracted 2026-07-07) -- confirmed "two-level reality" and the content/symbol/icon/medium representation-level passages verbatim; zero occurrences of "stratu" or "layer" as a general apparatus anywhere in the full text
• xwkont:ref:tupper-colore — TUpper COLORE formalization — verified directly against TUpper-Terms.html, tupper.all.owl, and tupper.clif (re-fetched 2026-07-07) -- zero occurrences of "stratu", "layer", or "level" in any of the three files, a stronger absence finding than the Codex draft's original "confined to timepoints" characterization
• xwkont:ref:gum-owl — GUM: The Generalized Upper Model — verified directly against GUM-31.owl.txt (re-fetched 2026-07-07 via the Wayback Machine snapshot) -- zero occurrences of "stratu" or "layer"; the four level occurrences are descriptive-generality/clause-scope prose, not measurement contexts as the Codex draft characterized them

Review History

Review ID	Date	Outcome	Notes
xwkont:review:ontological-level-stratum:2026-07-07:01	2026-07-07	Passed — advanced candidate → reviewed	Content originally drafted by Codex (external run, GPT-5.4-Mini, Extra-High reasoning) per the standing Codex-delegation process. All 8 sources independently re-verified against primary artifacts across two passes in the same session: GFO's Ontological_layer/Stratum/Level apparatus and UFO's UFO-A/UFO-B/UFO-C claim in the first pass; BFO, DOLCE, SUMO, YAMATO, TUpper, and GUM's absence/adjacent findings in a follow-up pass. One substantive correction to the Codex draft, resolved directly from evidence: UFO's UFO-A/UFO-B/UFO-C partition was framed as a second "explicit... strata" source, but the re-fetched 2021 paper uses zero stratification vocabulary and its substance duplicates continuant-occurrent.md/role.md content already -- recorded as explicit-non-equivalence. This finding was first (incorrectly) escalated as an open maintainer-decision question, then corrected after review: the facts plus this candidate's already-decided single-source (GFO-only) batch admission (2026-07-06) fully determined the outcome, so no maintainer decision was actually needed -- see the added "symmetric check" section in docs/methodology/crosswalk-runbook.md for the general lesson. Two minor corrections to source characterization also found and fixed: TUpper has zero stratum/layer/level vocabulary at all (not "confined to timepoints" as drafted); GUM's level occurrences are descriptive-generality prose, not "measurement" contexts as drafted. A fetch-path error was also corrected for BFO (21838-2/owl/bfo-core.ttl, not src/owl/bfo-core.ttl). This is a single-source (GFO) concept once UFO is properly excluded, consistent with the candidate's original 0.3.0 batch admission terms.

Future Work

• Optionally cross-reference the UFO-A/UFO-B/UFO-C vocabulary/duplication finding (uncertainty-001, resolved) back into continuant-occurrent.md and role.md's own Uncertainty sections for discoverability -- not required for this crosswalk.
• If GFO's base module ever drops the "Beta"/"work in progress" caveat on Ontological_layer in a future release, note the change; the caveat is currently recorded verbatim but does not affect this crosswalk's confidence in the apparatus's content.