Alexandra Arapinis : From ontological structures to semantic lexical structures: the case of...

From ontological structure to semantic lexicalstructure: the case of institutional entities

Alexandra Arapinis (Paris 1 - IHPST)

PHILOWEB 2010

16/10/2010

Alexandra Arapinis (Paris 1 - IHPST) PHILOWEB 2010 1

Outline

1 Systematic polysemy and names of institutions : a challenge forlexical resources

2 A (philosophical) incursion into institutional ontology

3 Handling systematic polysemy by interfacing ontologies andlexical resources


Outline





The polysemic character of institution denoting terms

Rephrasing test for polysemy : some semantic data

1. (a) The bank was very nice and understanding [individuals](b) The bank is right around the corner [building](c) The bank merged with the American Security Bank

[abstract institution]

2. (a) He’s on a trip with his school [individuals](b) The roof of the school is leaking [building](c) School was founded by Charles the Great [abstract

institution]

3. (a) The church was present at the manifestation [individuals](b) We go to church every Sunday [building](c) The Orthodox and Catholic church divided in 1054

[abstract institution]


Standard vs. systematic (regular or logical) polysemy

Coordination test

- Standard polysemy

“Ambiguity tests [. . .] utilise the fact that independent sensesof a lexical form are antagonistic to one another ; that is tosay, they cannot be brought into play simultaneously withoutoddness. Contexts which do activate more than one sense at atime give rise to [. . .] zeugma” ([Cruse86] : 61)

- Systematic polysemy

Though the intersection of the entities denoted by eachcontextual meaning of the word is empty (physical/individual/abstract) coordination tests are felicitous


Institution denoting terms and coordination

Compare

4. The bank went on strike [employees] in view of its upcoming mergerwith the American Security Bank [institution]

5. The school called me this morning [employees] to inform me that itwill be closed tomorrow [building]

6. The Catholic church, founded in 1054 [institution], is the worldslargest Christian church [members]

Vs.

7. ? ? John found the key to the mystery, but it doesn’t fit the lock

8. ? ? The key to success is very heavy


Systematic polysemy in WordNet

WordNet’s structure : quick reminder

- Structured in synsets (classes of synonyms), commonly takenas equivalent to concepts

- Synsets are in turn organized in hierarchies, defined byhypernym or IS-A relationships

- At the top level, these hierarchies are organized into basetypes, 25 primitive groups for nouns, and 15 for verbs

Representation of polysemy in WordNet

- Polysemy as multiple inheritance or multiple hypernymrelations

- Contrastive (homonymy) and complementary ambiguity(polysemy) are handled in the same way

IS-A overloading problem([Gangemi et al. 02, 03] [Guarino07]) multiple hypernymy generates

- logical incoherences- conceptual confusions


From the lexicon to ontology

Requirements for an adequate account of systematicpolysemy

- Introduction of complex categories of objects ([Pustejovsky95][Asher10] “dot-types”) : ’semantic facets’ linked throughnon-hierarchical relations

- Definition of orthogonal connections between categories andmechanisms of inheritance through such orthogonal relations

Working hypothesis

- Institutional as stratified entities (grounded in the materialrealm and on intentional agents involved in social interaction)

- The systematic polysemy as semantic upraisal of the complexontological structure of denoted entities

→ Understanding the patterns of systematic polysemy involvingnames of institutions requires understanding the patterns ofontological constitution of institutional entities


Outline





Descriptive common sense (social) ontology

A common semantic assumption in NLP

- Lexical semantic as the reflection of common sensecategorization of the world

Metaphysics of the “common sense world”

- Objects surrounding us in our everyday environment andactivities

- E.g. trees, rocks, rivers, but also chairs, tables, houses, banks,universities, etc.

General ontological assumptions

- Non-relativistic approach : there is an objective core structureof the common sense world as it is delivered trough differentcultures

- Non-reductionist approach : “ordinary objects” have properidentity and persistence conditions, viz. do not reduce to theontological building blocks studied in foundational ontology(material, intentional, abstract)


Philosophical background

The phenomenological tradition

- Husserl : study of the “lifeworld” or “personal world” as aproper ontological layer structured by multiple dependencerelations on “lower” layers

- Gotingen circle (Ingarden, Reinach) : ontological foundationsof the literary work, positive law, etc.

Recent advances at the joint between phenomenological andanalytic tradition

- Common sense metaphysics, developments and integration incontemporary analytical debates : B. Smith, A.L. Thomasson

- Development of a formal theory of dependence, taken as thefundamental ontological relation structuring reality : K. Fine,J. Lowe, P. Simons

The analytic tradition

- Searle’s social ontology grounded in his theory of intentionality(with divergences but also overlaps with the phenomenologicalapproach)


Institutions as “stratified” intentional products

Products of social acts (or collective intentionality) [Reinach,Searle]

- A social act (e.g. promises, commands, etc.) is such that itnecessarily involves : being produced in the direction of others,thus being externalized, and being grasped as such by others

→ Collective intentionality

- Social acts are productive, viz. something new comes intobeing : very roughly, new connections between agents hencebound into social-institutional groups

“Stratified” or “many-layered” entities [Ingarden]

- “Organic structures” or “formations” depend upon“heterogeneous” ontological strata for their existence andidentity (material, ideal, intentional)

- As such, these entities cannot be classified in either of themajor categories of objects accepted by traditionalmetaphysics, though they are grounded on them


The (quasi) abstract component of institutions

Deontic powers

- Drawing on the example of promises : paradigmatic pre-legalsocial acts

- Social acts produce claims and obligations regulating actions

Institutional roles

- Deontic powers are tied to institutional roles (e.g. president,employee), viz. place-holders for patterns of actions

- RLs are defined by (i) constitutive norms, determining theconditions under which an entity can qualify for role ; (ii)deontic norms, regulating the actions of players of a given role

Abstract artifacts

- Roles and deontic powers are not irreducible to intentionalstates nor material entities.

- (i) They are abstract in that they lack spatial location ; (ii)they are artifactual in being man-created, temporally located


The agentive component of institutions

Constant dependence on agents

- Deontic powers, like claims and obligations, can only existinsofar as there are people tied by them

- The dependence of such powers on agents consists in the factthat they cannot endure unless relevant bearers exist

Generic dependence on agents

- Institutional deontic powers do not tie specific individuals :they can be passed on from a bearer to another (e.g.replacement of the members of an organization)

- The perdurance of an institution only requires the existence ofsome individuals qualifying of the relevant institutional roles,viz. the existence of some bearer of the relevant deontic powers


The material component of institutions

Material objects invested with institutional status (role)The institutional status of material objects is derivative upon theactions of agents within the institution

(i) Institutions determine patterns of actions for the agentsplaying different institutional roles

(ii) These patterns (correlatively roles) include actions in relationto a material object

Two cases :

1. Determining the conditions under which a person is tied to“temporary institutional roles” may involve relationalconditions to a material entityA building housing an institutional activity (bank, university).Determines patterns of actions associated for people whilepresent in the building.

2. Institutional roles may involve regulated actions bearing on amaterial entityFrench national territory. The rights and duties of Frenchcitizens regulate ex. there movement on the French territory.


Outline





Ontology-driven revision of lexical resources

General strategy- Formalizing the fundamental categories and relations

structuring institutional entities in a top-level ontology

- Formulating principles of orthogonal quality-inheritance, inparticular quality-inheritance through dependence

- Aligning the top level of lexical resource with top-level ontology

Framework : DOLCE foundational ontology [Masolo et al.03]

- Alignment of WordNet’s upper level and DOLCE foundationalontology has been successfully achieved [Oltramary et al. 2002][Gangemi et al. 03]

- A preliminary characterization of social roles [Masolo et al. 04]and organizations [Bottazi&Ferrario 09] has been proposed inDOLCE

Aim : Show how orthogonal inheritance involved in institutionalentities can be formally characterized by focussing on the case oforganizations and bringing minimal extensions to existing results.


DOLCE basic categories

- ED(x) :“x is an endurant”, i.e. an entity that is wholly present atany time it is present

- PD(x) : “x is a perdurant”, i.e. an entity that extends through time,has temporal parts, and is only partially present at any given time

- APO(x) : “x is an agentive physical object”, i.e. an endurant thathas intentionality

- NAPO(x) : “x is an non-agentive physical object”, i.e. an endurantthat has no intentionality

- SOB(x) : “x is a social object”, i.e. an endurant that (i) is not aphysical object ; (ii) depends on a community of intentional agents

- PC(x, y, t) : the endurant x participates in the perdurant y at timet, i.e. endurants “involved” in an occurrence, typically an event


Extension to social individuals

Social individuals (SI(x)) (e.g. the bank of France, the Peugeotcompany) as social objects which can be described and definedusing a number of social concepts.

[Gangemi&Mika03] : Reifying concepts and descriptions to be ableto predicate on them :

CN(x) : “x is a social concept”DS(x) : “x is a description”

DF(x, y) : “x is defined by the description y”US(x, y) : “x is (re)used in the description y”CF(x, y, t) : “at time t, x is classified by the concept y”

[Bottazi&Ferrario09] : Modifying the argument restrictions for DFand US so that they can apply to social individuals

(A1) US(x , y) → ((CN(x) ∨ SI (x)) ∧ DS(y))(A2) DF (x , y) → US(x , y)(A3) (CN(x) ∨ SI (x) → ∃y (DF (x , y))(T1) DF (x , y) → ((CN(x) ∨ SI (x)) ∧ DS(y))


Some basic relations

Following [Bottazi&Ferrario09] :

Organizations, like any social object, are created by collectiveintentionality, viz. involve a social event (SEV(x))

This event links institutions and their defining descriptions throughsocial commitment, which “turns the description into a prescriptionfor agents”. This dimension is captured through the primitivevalidity relation (VAL(x, y))

(A4) VAL(x , y) → SI (y)∧DF (y , x)∧∃z , t (SEV (z)∧PC(x , z , t)∧PC(y , z , t)

New concepts and roles are created that have a meaning and a“legal status” inside the organization. These institutionalized(INST(x, y)) concepts and roles are introduced through validdescriptions

(D1) INST (x , y) =df CN(x) ∧ SI (y) ∧ ∃z (VAL(z , y) ∧ US(x , z))


Social roles

Based on the notion of social role (RL(x)), we distinguish agentive andnon-agentive roles, depending on the kind of entity classified by a role(CF(x, y, t) [Masolo et al 04]).

Agentive roles regulate the behavior that agents must observe whenthey play definite roles.“x is an agentive role in y” (ARL(x, y)) isdefined by

(D2) ARL(x , y) =df RL(x) ∧ INST (x , y) ∧ ∀z , t (CF (z , x , t) → APO(z))

Non-agentive roles (NARL(x, y)) regulate actions of agentsinvolving the object invested with the given role. They areinstitutionalized insofar as they are ’definitional’ of the agentiveroles.

The requirement relation (RQ(x, y) :“x requires y”) captures this’definitional’ connection through :

(A5) (RQ(x , y) ∧ DF (x , d)) → US(y , d)

(D3) NARL(x , y) =df RL(x) ∧ ∀z , t (CF (z , x , t) → NAPO(z))∧∀v (ARL(v , y) → RQ(v , x))


Partial characterization of organizations

Relations connecting agents and non-agentive physical objects to socialindividuals (drawing on and extending [Bottazi&Ferrario09]) :

“x is affiliated to y at time t”

(A6) AFF (x , y , t) → ∃z ARL(z , y) ∧ CF (x , z , t)

“x counts as y at time t” (following Searle)

(A7) CNT (x , y , t) → ∃z NARL(z , y) ∧ CF (x , z , t)

Necessary conditions for a social individual to be an organization, usingthe relation of being present a time t (PRE (x , t))

“x is an organization”

(A8) ORG(x) → ∃t (PRE(x , t) ∧ ∀t′ (PRE(x , t′) → ∃y AFF (y , x , t′))

“x is a materially grounded organisation”

(D4) MORG(x) =df ORG(x) ∧ ∀t (PRE(x , t) → ∃y CNT (y , x , t))


Organizations and dependence

The dependences structuring organizations :

One important axiom of the CF relation :

(A9) CF (x , y , t) → PRE(x , t)

From the definition of Generic Constant Dependence (GD(φ, ψ))

(D5) GD(φ, ψ) =df �(∀x(φ(x) → ∃t(PRE(x , t))∧∀x , t((φ(x)∧PRE(x , t)) → ∃y(ψ(y)∧PRE(x , t)))

and (A9) the following theorems can be prouved :

(T2) GD(ORG ,AFF )

(T3) GD(MORG ,AFF )

(T4) GD(MORG ,CNT )

[(T) SD(ORG ,DS)]


Indirect quality-inheritance

Kinds of qualities

- TQ(x) : “x is a temporal quality”

- SQ(x) : “x is a spatial quality ”

- AQ(x) : “x is an abstract quality”

- To which we add AGQ(x) : “x is an agentive quality”

Extending argument restrictions (where qt(x, y) is read “x is aquality of y” and Kx stands for “the kind of x”)

(A10) qt(x , y) ↔ (TQ(x) → D(Ky ,PD))

(A11) qt(x , y) ↔ (SQ(x) → D(Ky ,ED))

(A12) qt(x , y) ↔ (AQ(x) → D(Ky ,NPED))

(A13) qt(x , y) ↔ (AGQ(x) → D(Ky ,APO))


Remarks on indirect inheritance

Note that :

(A10- A12) cover the original argument constraints on qualitiesfrom DOLCE :

(i) a PD(resp. ED, NPED, APO) is constantly dependent onitself,

(ii) a TQ (resp. SQ, AQ, AGQ) is constantly dependent on PD(resp. ED, NPED, APO)

Indirect inheritance extends beyond the category of socialindividuals to all cases of constant dependence

Axioms stipulating that a PD indirectly inherits SQ from itsparticipants, and that a PED indirectly inherits TQ from the eventit participates to follow as theorems


Perspectives

Concerning institutional ontology

- Further exploit philosophical literature in the ontology ofinstitutional entities and in particular its recent developments(e.g. legal, geographic)

- Pursue the formal characterization of social individuals andrelations

Concerning the ontology/lexical resource interface

- Extending and testing the hypothesis of a correlation betweensystematic polysemy and ontological dependence

- Use systematic polysemy detection in WordNet (viz. multiplehypernym detection) as a tool to reveal underlying ontologicaldependences

- Draw general patterns of dependence and integrate them infoundational ontologies like DOLCE


.

Thank you !


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