Documentation

Linglib.Core.Discourse.Coherence

Discourse Coherence Relations #

@cite{hobbs-1979} @cite{kehler-2002} @cite{umbach-2004}

Coherence relations classify how adjacent discourse segments connect. Each relation belongs to one of three classes (resemblance, cause–effect, contiguity) and has a directionality that determines which segment provides the cause/explanation.

Key insight for IC bias #

@cite{kehler-2002} argues that coherence relations determine which participant listeners seek as a cause/explanation in sentence continuations:

Explanation ("because"): backward causal — listeners seek the cause of the event described in the first clause
Result ("so"): forward causal — listeners infer the effect
Occasion ("and then"): temporal contiguity — no causal search

This interacts with verb semantics to produce implicit causality (IC) bias. @cite{solstad-bott-2022} @cite{solstad-bott-2024}

Contrast vs Correction #

@cite{umbach-2004} argues that both CONTRAST and CORRECTION are resemblance relations requiring alternatives that are similar (common integrator) and dissimilar (semantically independent). They differ in their type of exclusion:

CONTRAST: excludes additional alternatives (the second alternative holds in addition to the first; "but" with confirm+deny)
CORRECTION: excludes by substitution (the second alternative holds instead of the first; German sondern, English corrective "but")

Both are distinct from PARALLEL/SEQUENCE ("and"-coordination), which requires similarity+dissimilarity but no exclusion.

inductive Core.Discourse.Coherence.CoherenceClass :

Kehler's three coherence classes, corresponding to Hume's three associative connections between ideas.

resemblance : CoherenceClass
causeEffect : CoherenceClass
contiguity : CoherenceClass

Instances For

@[implicit_reducible]

instance Core.Discourse.Coherence.instDecidableEqCoherenceClass :

DecidableEq CoherenceClass

Equations

Core.Discourse.Coherence.instDecidableEqCoherenceClass x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

@[implicit_reducible]

instance Core.Discourse.Coherence.instReprCoherenceClass :

Repr CoherenceClass

Equations

Core.Discourse.Coherence.instReprCoherenceClass = { reprPrec := Core.Discourse.Coherence.instReprCoherenceClass.repr }

def Core.Discourse.Coherence.instReprCoherenceClass.repr :

CoherenceClass → Nat → Std.Format

Equations

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

Instances For

inductive Core.Discourse.Coherence.CoherenceRelation :

Individual discourse coherence relations. Each relation specifies how the current segment connects to the prior one.

@cite{umbach-2004} §3: CONTRAST and CORRECTION are distinct resemblance relations that both require similarity+dissimilarity in their alternatives but differ in their exclusion type.

@cite{asher-lascarides-2003} §4.6 contributes BACKGROUND, CONSEQUENCE, and ALTERNATION. SDRT's "Narration" relation is the same as Hobbs/Kehler's occasion — both denote temporal succession of events. Use occasion in code; the Narration alias below is provided for SDRT-flavored code that prefers Asher-Lascarides terminology.

explanation : CoherenceRelation
result : CoherenceRelation
occasion : CoherenceRelation
elaboration : CoherenceRelation
parallel : CoherenceRelation
contrast : CoherenceRelation
correction : CoherenceRelation
background : CoherenceRelation
consequence : CoherenceRelation
alternation : CoherenceRelation

Instances For

@[implicit_reducible]

instance Core.Discourse.Coherence.instDecidableEqCoherenceRelation :

DecidableEq CoherenceRelation

Equations

Core.Discourse.Coherence.instDecidableEqCoherenceRelation x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

def Core.Discourse.Coherence.instReprCoherenceRelation.repr :

CoherenceRelation → Nat → Std.Format

Equations

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

Instances For

@[implicit_reducible]

instance Core.Discourse.Coherence.instReprCoherenceRelation :

Repr CoherenceRelation

Equations

Core.Discourse.Coherence.instReprCoherenceRelation = { reprPrec := Core.Discourse.Coherence.instReprCoherenceRelation.repr }

@[reducible, inline]

abbrev Core.Discourse.Coherence.CoherenceRelation.Narration :

CoherenceRelation

Asher-Lascarides "Narration" = Hobbs/Kehler "Occasion". Provided so SDRT-flavored code can write .Narration if desired. Both names refer to the same underlying relation (temporal succession).

Equations

Core.Discourse.Coherence.CoherenceRelation.Narration = Core.Discourse.Coherence.CoherenceRelation.occasion

Instances For

def Core.Discourse.Coherence.CoherenceRelation.toClass :

CoherenceRelation → CoherenceClass

Classify each relation into its coherence class.

SDRT additions: background is a contiguity relation (β provides spatiotemporal setting for α); consequence is a causal relation (the discourse-level analog of "if A then B"); alternation is a resemblance relation (alternatives sharing a common integrator but with exclusion).

Equations

Instances For

inductive Core.Discourse.Coherence.CausalDirection :

Causal direction: does the relation seek a cause in the prior segment?

backward : CausalDirection
forward : CausalDirection
none : CausalDirection

Instances For

@[implicit_reducible]

instance Core.Discourse.Coherence.instDecidableEqCausalDirection :

DecidableEq CausalDirection

Equations

Core.Discourse.Coherence.instDecidableEqCausalDirection x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

@[implicit_reducible]

instance Core.Discourse.Coherence.instReprCausalDirection :

Repr CausalDirection

Equations

Core.Discourse.Coherence.instReprCausalDirection = { reprPrec := Core.Discourse.Coherence.instReprCausalDirection.repr }

def Core.Discourse.Coherence.instReprCausalDirection.repr :

CausalDirection → Nat → Std.Format

Equations

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

Instances For

def Core.Discourse.Coherence.CoherenceRelation.causalDirection :

CoherenceRelation → CausalDirection

The causal direction of each relation.

Equations

Instances For

def Core.Discourse.Coherence.CoherenceRelation.selectsCause (r : CoherenceRelation) :

Bool

Does this relation trigger a search for a cause?

Equations

r.selectsCause = (r.causalDirection == Core.Discourse.Coherence.CausalDirection.backward)

Instances For

def Core.Discourse.Coherence.CoherenceRelation.selectsEffect (r : CoherenceRelation) :

Bool

Does this relation trigger a search for an effect?

Equations

r.selectsEffect = (r.causalDirection == Core.Discourse.Coherence.CausalDirection.forward)

Instances For

inductive Core.Discourse.Coherence.Connective :

German/English connective forms used as experimental stimuli (@cite{solstad-bott-2022}, Exps 1–4).

because : Connective
andSo : Connective
although : Connective
andThen : Connective

Instances For

@[implicit_reducible]

instance Core.Discourse.Coherence.instDecidableEqConnective :

DecidableEq Connective

Equations

Core.Discourse.Coherence.instDecidableEqConnective x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

def Core.Discourse.Coherence.instReprConnective.repr :

Connective → Nat → Std.Format

Equations

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

Instances For

@[implicit_reducible]

instance Core.Discourse.Coherence.instReprConnective :

Repr Connective

Equations

Core.Discourse.Coherence.instReprConnective = { reprPrec := Core.Discourse.Coherence.instReprConnective.repr }

def Core.Discourse.Coherence.Connective.toRelation :

Connective → CoherenceRelation

Map connectives to the coherence relation they signal.

Equations

Instances For

theorem Core.Discourse.Coherence.because_selects_cause :

Connective.because.toRelation.selectsCause = true

"because" selects for causes (backward causal).

theorem Core.Discourse.Coherence.andSo_selects_effect :

Connective.andSo.toRelation.selectsEffect = true

"and so" selects for effects (forward causal / I-Cons).

theorem Core.Discourse.Coherence.although_not_causal :

Connective.although.toRelation.selectsCause = false

"although" does not select for causes.

theorem Core.Discourse.Coherence.andThen_not_causal :

Connective.andThen.toRelation.selectsCause = false

"and then" does not select for causes.

theorem Core.Discourse.Coherence.because_andSo_opposite_directions :

Connective.because.toRelation.causalDirection = CausalDirection.backward ∧ Connective.andSo.toRelation.causalDirection = CausalDirection.forward

"because" and "and so" are both causal but in opposite directions: I-Caus is backward, I-Cons is forward.

theorem Core.Discourse.Coherence.causal_relations_same_class :

CoherenceRelation.explanation.toClass = CoherenceRelation.result.toClass

Both causal relations (explanation, result) belong to causeEffect class.

theorem Core.Discourse.Coherence.contiguity_relations_same_class :

CoherenceRelation.occasion.toClass = CoherenceRelation.elaboration.toClass

Occasion and elaboration belong to contiguity class.

theorem Core.Discourse.Coherence.contrast_correction_same_class :

CoherenceRelation.contrast.toClass = CoherenceRelation.correction.toClass

CONTRAST and CORRECTION are both resemblance relations (@cite{umbach-2004} §3.2, @cite{kehler-2002}).

theorem Core.Discourse.Coherence.contrast_ne_correction :

CoherenceRelation.contrast ≠ CoherenceRelation.correction

CONTRAST and CORRECTION are distinct relations despite sharing a class. @cite{umbach-2004} §3.2: they differ in exclusion type (additional vs substitution) and in the implicit question they respond to. German lexicalizes the difference: aber (contrast) vs sondern (correction).