Head determination criteria #

Classification of Universal Dependencies relations by how prototypically "head-dependent" they are, following [Hud90]'s six criteria: category determination, semantic determination, obligatoriness, selection, morphological determination, and positional determination. The classifier buckets each UD relation into core argument, modifier, or function-word class, and expectedCriteriaCount records how many of the six criteria each class typically satisfies — capturing Hudson's prototype-theoretic observation that "head" admits degrees rather than a sharp boundary.

Main declarations #

RelationClass — three-way bucketing of UD relations.
classifyRelation — UD.DepRel → RelationClass.
expectedCriteriaCount — number of Hudson criteria each class satisfies.

Implementation notes #

Earlier drafts shipped a HeadCriterion record bundling a String name with a Bool satisfied predicate, plus stipulated List String "evidence" records for individual UD relations. That material encoded conclusions as data and used String in proof-relevant positions; it has been dropped. A future revision should derive each criterion structurally from Dependency and the surrounding tree.

Classification of UD relations #

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inductive DepGrammar.HeadCriteria.RelationClass :

Type

Three-way bucketing of UD relations by how prototypically head-dependent they are.

coreArgument : RelationClass
Core arguments (nsubj, obj, …): satisfy all six criteria.
modifier : RelationClass
Modifiers (amod, advmod, …): obligatoriness typically fails.
functionWord : RelationClass
Function-word relations (det, aux, case, …): controversial.

Instances For

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@[implicit_reducible]

instance DepGrammar.HeadCriteria.instReprRelationClass :

Repr RelationClass

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DepGrammar.HeadCriteria.instReprRelationClass = { reprPrec := DepGrammar.HeadCriteria.instReprRelationClass.repr }

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def DepGrammar.HeadCriteria.instReprRelationClass.repr :

RelationClass → ℕ → Std.Format

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One or more equations did not get rendered due to their size.

Instances For

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@[implicit_reducible]

instance DepGrammar.HeadCriteria.instDecidableEqRelationClass :

DecidableEq RelationClass

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DepGrammar.HeadCriteria.instDecidableEqRelationClass x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

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def DepGrammar.HeadCriteria.classifyRelation :

UD.DepRel → RelationClass

Classify a UD relation by how prototypically "head-dependent" it is. Core arguments and clausal complements bucket as coreArgument; modifiers and obliques as modifier; function-word relations as functionWord.

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Instances For

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def DepGrammar.HeadCriteria.expectedCriteriaCount :

RelationClass → ℕ

Number of Hudson criteria each relation class typically satisfies: core arguments satisfy all six; modifiers typically fail obligatoriness and one positional criterion; function-word relations are controversial.

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