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

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Presentation on theme: "Synonymies and conceptual vectors NLPRS 2001 Mathieu Lafourcade, Violaine Prince LIRMM - France."— Presentation transcript:

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

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

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

4 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}*

5 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

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

7 Conceptual vectors Term peace c4:peace

8 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

9 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)

10 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 …

11 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 ?

12 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)

13 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

14 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

15 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)

16 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

17 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)

18 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

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

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

21 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

22 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 System in continuous learning Evolving results Hopefully converging


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