# Synonymies and conceptual vectors NLPRS 2001 Mathieu Lafourcade, Violaine Prince LIRMM - France.

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Synonymies and conceptual vectors NLPRS 2001 Mathieu Lafourcade, Violaine Prince LIRMM - France

Overwiew & Objectives why synonymy? what : Conceptual vectors which synonymies ? for what : Use with lexical functions

Evaluation Semantic proxymity to possible contexts for lexical interchangeability Relative synonymy Elimination of transitivity punctum proximum Subjective synonymy punctum remotum Objectives

Conceptual vectors vector space An idea Concept combination a vector Idea space = vector space A concept = an idea = a vector V with augmentation: V + neighboorhood Meaning space = vector space + {v}*

Conceptual vectors Thesaurus H : thesaurus hierarchy K concepts Thesaurus Larousse = 873 concepts V(C i ) : a j = 1/ (2 ** D um (H, i, j)) 1/41 1/16 1/64 264

Conceptual vectors Concept c4:peace peace hiérarchical relations conflict relations The world, manhood society

Conceptual vectors Term peace c4:peace

Angular distance D A (x, y) = angle (x, y) 0 D A (x, y) if 0 then x & y colinear same idea if /2 then nothing in common if then D A (x, -x) with -x anti-idea of x x y x

Angular distance D A (x, y) = acos(sim(x,y)) D A (x, y) = acos(x.y/|x||y|)) D A (x, x) = 0 D A (x, y) = D A (y, x) D A (x, y) + D A (y, z) D A (x, z) D A (0, 0) = 0 and D A (x, 0) = /2 by definition D A ( x, y) = D A (x, y) with 0 D A ( x, y) = - D A (x, y) with < 0 D A (x+x, x+y) = D A (x, x+y) D A (x, y)

Thematic distance Examples D A (tit, tit) = 0 D A (tit, passerine) = 0.4 D A (tit, bird) = 0.7 D A (tit, train) = 1.14 D A (tit, insect) = 0.62 tit = insectivorous passerine bird …

Relative synonymy Aspectual or referential Term polysemy un personnel trié sur le volet (CHOISIR) une liste triée par ordre alphabétique (ORDONNER) le courrier est trié (REPARTIR) A vector plays as an aspect (aka reference) How can we exchange A & B in the context of C ?

Relative synonymy Syn R (A, B, C) with C as a reference (ref) Syn R (A, B, C) = D A (A+A C, B+B C) B A C A+A C B+B C Syn R (A, B, C)

Relative synonymy Properties Syn R (A, B, C) = Syn R (B, A, C) Syn R (A, A, C) = D A (A C, A C) = 0 Syn R (A, B, 0) = D A (A, B Syn R (A, 0, C) = /2 D A (charbon,nuit) = 0.9 Syn R (charbon, nuit, couleur) = 0.4 Syn R (charbon, nuit, noir) = 0.35

Relative synonymy Properties The relative synonymy is a measure which favors the closing in of 2 vectors: black a good punctum proximum for coal and night Transitivity of the synonymy Syn R (coal, crow, black) = 0.18 Syn R (crow, night, black) = 0.5 Syn R (coal, night, black) = 0.35

Absolute synonymy Syn A (A, B) a particular case with A B as ref Syn A (A, B) = Syn R (A, B, A B) B A A B A+A A B) B+B (A B) Syn A (A, B)

Subjective synonymy Point of view Semantic discrimination scope D A (tit, bird) = 0.7 D A (sparrow, bird)= 0.48 D A (tit, sparrow)= 0.23 With which pow can we discriminate two given vectors? Closest punctum remotum

Subjective synonymy Syn S (A, B, C) C = point of view (pow) Syn S (A, B, C) = D( A-A C, B-B C ) B A C A-A C B-B C Syn S (A, B, C)

Subjective synonymy When D A (A, C) /2 & D A (B, C) /2 then Syn S (A, B, C) D A (A,B) Syn S (A, B, 0) = D A (A, B) Syn S (A, A, C) = 0 Syn S (A, B, B) = D A (A-A B, 0) = /2 D A (tit, crow) = 0.32 Syn S (tit, crow, zoology) = 0.54 Syn S (tit, crow, bird) = 1.07 Syn S (tit, crow, passerine) = 1.37

Subjective synonymy Properties non conservation of the concept hierarchy chain Concept chain @the_world > @the_life > @animals > @birds D A (tit, sparrow) = 0.23 Syn S (tit, sparrow, @the_life) = 0.75 Syn S (tit, sparrow, @the_world) = 0.5 Syn S (tit, sparrow, @animals) = 0.4 Syn S (tit, sparrow, @birds) = 0.9 Concepts horizon (at the lowest concept level)

Subjective synonymy Properties Polysemy: term vs concept Syn S (tit, sparrow, @birds) = 0.9 Syn S (tit, sparrow, bird) = 0.78 Loosly correlated vectors as pow Syn S (tit, sparrow, @gold)= 0.7 D A (tit, @gold)= 1.19 D A (sparrow, @gold)= 1.15

Objective synonymy Syn A (A, B) a particular case with A B as pow Syn A (A, B) = Syn A (A, B, A B) B A A-A (A B) B-B (A B) Syn A (A, B) A B

Conclusion Synonymy as enhancement of the thematic analysis The conceptual vector models shows interferencies from polysemy : relative synonymy from the complex relation btw concept and terms (bird vs @birds) System in continuous learning Evolving results Hopefully converging