{ "model": { "rank": 8769, "code": "thing-q223655", "model_id": "vr.tr.tree-q223655", "name": "tree", "purpose": "Let an agent reason about tree-shaped data as a structure with invariants that can be checked and broken, rather than as a picture of a hierarchy.", "family": "Thing Registry", "category": "Information and virtual systems", "status": "research-draft", "kind": "thing", "plane": "INF", "domain": "INF.KNW", "industry": "", "version": "", "url": "/models/thing/q223655/", "tier": 2, "score": 50, "payload": { "layer": "wikidata", "aliases": [ "virtual file system", "brodal queue", "d-ary heap", "pagoda", "random binary tree", "SMB share", "octree", "R-tree", "disjoint-set data structure", "hash tree", "multi-way tree", "heap", "B+ tree", "SPQR tree", "balanced tree", "complete tree", "digital tree", "digital search tree", "Euclidean Steiner tree", "finitary tree", "BSP tree", "binomial tree", "binary tree", "M-tree", "X-tree", "adaptive k-d tree", "Enfilade", "exponential tree", "FM-index", "interval tree", "R*-tree", "R+ tree", "link/cut tree", "Metric tree", "range tree", "Van Emde Boas tree", "quadtree", "rope", "ternary heap", "treap" ], "aliasCount": 72, "merged": 72, "knownIn": 50, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": "vr.tr.tree", "source": { "dataset": "wikidata", "item": "Q223655", "url": "https://www.wikidata.org/wiki/Q223655", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-11T04:06:21Z", "providers": [ "Claude" ], "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify", "pass": 2, "wave": 1, "engine": "claude" }, "metaModel": { "id": "THING-Q223655", "registryId": "vr.tr.tree-q223655", "name": "tree", "version": "0.2.0-wave.1", "entryKind": "thing", "family": "Thing Registry", "domain": [ "INF.KNW" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q223655/", "model": { "registry_id": "vr.tr.tree-q223655", "name": "tree", "purpose": "Let an agent reason about tree-shaped data as a structure with invariants that can be checked and broken, rather than as a picture of a hierarchy.", "definition": "A data structure of nodes connected so that each node has exactly one parent except a single root, and no cycles exist.", "what_it_is_for": "Representing containment, classification, decomposition and any relation where each thing has one place and that place has a path to a root.", "affordances": [ "traverse it, in orders that give different results", "insert, move and delete nodes, each of which can break an invariant", "compute depth, ancestry and subtree size, which is why it is used", "break it by creating a cycle or a second parent, producing something that is no longer a tree" ], "distinguishing_features": [ "Exactly one root and one parent per node, which separates it from a general graph and from a forest", "Acyclic by definition: a cycle means it was never a tree", "Ordered and unordered trees are different structures with the same picture", "The structure and the thing it represents are different: a classification is not a tree, it is modelled as one" ], "appearance": "Nothing to see. Drawings of trees are a convention, and the same structure is drawn root-up, root-down or sideways with no difference in meaning.", "visual_identification": [ "A drawing is not the structure; the invariants are what identify it", "A picture that looks like a tree may be a graph with hidden extra edges", "The only reliable check is structural: one root, one parent per node, no cycles" ], "physical_properties": [ { "quantity": "depth", "typical_range": "1-40", "unit": "levels", "note": "deep trees cause recursion limits and slow lookups" }, { "quantity": "branching factor", "typical_range": "2-1000", "unit": "children per node", "note": "" }, { "quantity": "node count", "typical_range": "1-10000000", "unit": "nodes", "note": "" } ], "families_and_kinds": [ "by shape rule: binary, n-ary, balanced, trie", "by ordering: ordered, unordered", "by storage: pointer, adjacency list, nested set, materialised path", "by use: index, syntax tree, file system, taxonomy" ], "related_models": [ { "relation": "is a kind of", "target": "graph", "why": "a tree is a graph with extra constraints, and losing them makes it a graph again" }, { "relation": "is confused with", "target": "tree the plant", "why": "a homonym; this entry is the data structure and carries none of the biology" }, { "relation": "represents", "target": "hierarchy", "why": "the hierarchy is the subject matter; the tree is the representation and can misrepresent it" }, { "relation": "is confused with", "target": "directed acyclic graph", "why": "a DAG allows several parents, which is exactly the constraint a tree adds" } ], "identifiers": [], "standards_and_regulation": [], "failure_modes_and_hazards": [ "Cycles introduced by a move operation, which turns traversal into an infinite loop", "Orphaned nodes after a delete, which leave the structure invalid rather than smaller", "Depth beyond what recursion can handle, producing stack exhaustion", "Modelling as a tree something that genuinely has several parents, which forces data to be duplicated or lost" ], "in_scope": [], "out_of_scope": [], "characteristics": [] }, "sources": [], "structure": { "bundles": [ { "id": "structure-and-invariants", "name": "Structure and invariants", "description": "What makes it a tree and what breaks it.", "rationale": "A tree is defined by constraints rather than by shape, and every useful property follows from those constraints holding.", "layers": [ { "id": "invariants", "name": "Invariants", "description": "One root, one parent, no cycles.", "findings": [ { "id": "invariants-finding", "name": "Invariants and their enforcement", "description": "Which constraints hold and what enforces them.", "questions": [ { "text": "Which invariants does this structure maintain, and what enforces each?", "kind": "definition" }, { "text": "What operation could break each one, and how would that be detected?", "kind": "boundary" } ] } ] }, { "id": "ordering", "name": "Ordering and identity", "description": "Whether children are ordered and how nodes are named.", "findings": [ { "id": "ordering-finding", "name": "Ordering and node identity", "description": "Whether order carries meaning and what identifies a node.", "questions": [ { "text": "Is this tree ordered, and does the order carry meaning?", "kind": "definition" }, { "text": "What identifies a node independently of its position?", "kind": "provenance" } ] } ] } ] }, { "id": "operations-and-cost", "name": "Operations and cost", "description": "What can be done and what it costs.", "rationale": "The reason to model something as a tree is the cost of its operations, so those costs belong in the model.", "layers": [ { "id": "traversal", "name": "Traversal", "description": "Orders of visiting and what each yields.", "findings": [ { "id": "traversal-finding", "name": "Traversal orders", "description": "The orders available and their uses.", "questions": [ { "text": "Which traversal orders are meaningful here, and what does each produce?", "kind": "definition" }, { "text": "What is the cost of each traversal in this representation?", "kind": "measurement" } ] } ] }, { "id": "mutation", "name": "Mutation", "description": "Insert, move, delete and rebalance.", "findings": [ { "id": "mutation-finding", "name": "Mutation and its risks", "description": "What changes the structure and what it endangers.", "questions": [ { "text": "Which mutations are supported, and at what cost?", "kind": "measurement" }, { "text": "Which mutation is most likely to leave the structure invalid, and what guards it?", "kind": "action" } ] } ] } ] }, { "id": "representation-and-storage", "name": "Representation and storage", "description": "How it is actually stored.", "rationale": "The same tree stored four ways has four different performance profiles and four different failure modes.", "layers": [ { "id": "storage", "name": "Storage form", "description": "Pointers, adjacency, nested sets, paths.", "findings": [ { "id": "storage-finding", "name": "Storage representation", "description": "How the structure is materialised.", "questions": [ { "text": "How is this tree stored, and what does that make cheap or expensive?", "kind": "definition" }, { "text": "What breaks in that representation when the tree is reorganised?", "kind": "boundary" } ] } ] }, { "id": "limits", "name": "Limits", "description": "Depth, size and the boundaries of the implementation.", "findings": [ { "id": "limits-finding", "name": "Implementation limits", "description": "Where the representation stops working.", "questions": [ { "text": "What depth and size can this representation handle?", "kind": "measurement" }, { "text": "What should happen when those limits are approached?", "kind": "action" } ] } ] } ] }, { "id": "fit-to-the-domain", "name": "Fit to the domain", "description": "Whether the world being modelled is really a tree.", "rationale": "Most real hierarchies are not trees, and forcing them into one is the modelling error this entry exists to flag.", "layers": [ { "id": "domain-fit", "name": "Domain fit", "description": "Whether the subject has one parent per item.", "findings": [ { "id": "domain-fit-finding", "name": "Fitness of the structure", "description": "Where the domain resists the tree constraint.", "questions": [ { "text": "Does every item in the domain have exactly one parent, and how is that established?", "kind": "boundary" }, { "text": "Which real cases have several parents, and how are they currently handled?", "kind": "definition" } ] } ] }, { "id": "alternatives", "name": "Alternatives", "description": "What to use when it is not a tree.", "findings": [ { "id": "alternatives-finding", "name": "When to use something else", "description": "The structures that fit better and what they cost.", "questions": [ { "text": "What structure fits when the tree constraint fails, and what is lost by switching?", "kind": "action" }, { "text": "How should a partial or approximate hierarchy be recorded honestly?", "kind": "action" } ] } ] } ] } ] }, "openQuestions": [ "Should the registry separate the abstract structure from its storage representations, since the invariants hold for all and the costs differ?", "How should a model express that a domain is almost a tree, which is the usual real case?", "What is the right way to record which invariant a particular implementation enforces and which it merely assumes?" ], "statistics": { "bundles": 4, "layers": 8, "findings": 8, "questions": 16 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "discipline or field of knowledge", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a tree, record what state it is in, and decide what may be done with it.", "whatItIs": "Let an agent reason about tree-shaped data as a structure with invariants that can be checked and broken, rather than as a picture of a hierarchy.", "characteristics": { "substance": "information", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "read and interpreted" ], "distinguishingFeatures": [ "Names folded into this entry, which a task may need to split apart again: virtual file system, brodal queue, d-ary heap, pagoda, random binary tree, SMB share, octree, R-tree, disjoint-set data structure, hash tree, multi-way tree, heap.", "72 finer distinctions are held as aliases rather than separate entries, because telling them apart needs a task that asks for it.", "Described in 50 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a tree, and on what evidence are they told apart?" ], "whatItIsMadeOf": "content that has to be carried by something else", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "read it and act on what it says" ], "howItIsRecognised": [], "relatedModels": [ { "relation": "covers", "note": "Finer kinds folded into this entry because telling them apart needs a task that asks for it. Each is a model waiting to be split out when one does.", "targets": [ "virtual file system", "brodal queue", "d-ary heap", "pagoda", "random binary tree", "SMB share", "octree", "R-tree", "disjoint-set data structure", "hash tree", "multi-way tree", "heap" ] } ], "standing": "Described in 50 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is. 72 finer distinctions are held inside this entry as names rather than as separate models.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one tree from another, and a tree from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a tree sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a tree from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a tree passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a tree between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a tree, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a tree is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "content-and-access", "name": "Content, encoding and access", "description": "What a tree says, how it is encoded and who may read it.", "rationale": "An informational thing carries content that can be copied, versioned and withheld, none of which its physical carrier explains.", "layers": [ { "id": "content-and-encoding", "name": "Content and encoding", "description": "The content itself, its format and its language.", "findings": [ { "id": "content-and-format", "name": "Content, format and language", "description": "What a tree contains and in what form it is held.", "questions": [ { "id": "content-and-format-q01", "text": "What identifies and describes the content of a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "content-and-format-q02", "text": "Who or what asserted this about the content of a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "content-and-format-q03", "text": "What may an agent decide or do once the content of a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "access-and-rights", "name": "Access, rights and retention", "description": "Who may read, copy or change it, and for how long it is kept.", "findings": [ { "id": "access-rules", "name": "Access rules and retention", "description": "The permissions attached to a tree and the period it survives.", "questions": [ { "id": "access-rules-q01", "text": "What identifies and describes access to a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "access-rules-q02", "text": "Who or what asserted this about access to a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "access-rules-q03", "text": "What may an agent decide or do once access to a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "subject-and-method", "name": "Subject matter and method", "description": "What tree studies and how it establishes anything.", "rationale": "A field is identified by its questions and its methods, and those are what distinguish it from the fields next to it.", "layers": [ { "id": "subject", "name": "Subject matter", "description": "The questions it takes as its own.", "findings": [ { "id": "subject-record", "name": "Questions and objects of study", "description": "What it is about, stated so a neighbouring field can be told apart.", "questions": [ { "id": "subject-record-q01", "text": "What questions and objects does tree take as its own?", "kind": "definition" }, { "id": "subject-record-q02", "text": "Which questions does it share with a neighbouring field, and who claims them?", "kind": "boundary" } ] } ] }, { "id": "method", "name": "Method and evidence", "description": "How claims are established and what counts as evidence.", "findings": [ { "id": "method-record", "name": "Methods and standards of evidence", "description": "The methods used and what they are taken to establish.", "questions": [ { "id": "method-record-q01", "text": "By what methods does tree establish claims, and what counts as sufficient evidence?", "kind": "provenance" }, { "id": "method-record-q02", "text": "What kind of claim can this field not settle, and where should an agent look instead?", "kind": "action" } ] } ] } ] }, { "id": "institutions-and-classification", "name": "Institutions and classification", "description": "Where tree is practised and how catalogues place it.", "rationale": "The institutional footprint is the evidence that a field exists as a field rather than as a topic.", "layers": [ { "id": "institutions", "name": "Institutional markers", "description": "Societies, journals, degrees and departments.", "findings": [ { "id": "institution-record", "name": "Bodies and venues", "description": "Where the field organises itself.", "questions": [ { "id": "institution-record-q01", "text": "Which societies, journals or degrees mark tree as an established field?", "kind": "provenance" }, { "id": "institution-record-q02", "text": "What would show that it is emerging or dissolving rather than established?", "kind": "boundary" } ] } ] }, { "id": "classification", "name": "Classification schemes", "description": "Where library and research classifications put it.", "findings": [ { "id": "classification-record", "name": "Codes and their disagreements", "description": "The classification codes that place it, and where they differ.", "questions": [ { "id": "classification-record-q01", "text": "Which classification schemes place tree, under what codes?", "kind": "definition" }, { "id": "classification-record-q02", "text": "Where do those schemes disagree about its scope?", "kind": "boundary" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a tree came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a tree and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a tree is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a tree, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a tree, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a tree is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 6, "layers": 12, "findings": 14, "questions": 38 } } } }