1. A relationship information expansion apparatus stored in a processor comprising: a relationship information storage unit in which a relationship information piece including two or more language expressions having a semantic relationship is stored; a similarity information storage unit in which two or more similarity information pieces each including two or more similar language expressions are stored; a candidate expanded relationship information storage unit in which a candidate expanded relationship information piece, which is the relationship information piece in which at least one language expression was replaced with a similar language expression, is stored; a candidate expanded relationship information generation unit for generating a candidate expanded relationship information piece from the relationship information piece stored in the relationship information storage unit by replacing at least one language expression in the relationship information piece with a language expression similar to the at least one language expression, using the similarity information pieces, and accumulating the candidate expanded relationship information piece in the candidate expanded relationship information storage unit; a score acquisition unit for acquiring a score that indicates a probability that the candidate expanded relationship information piece stored in the candidate expanded relationship information storage unit has a semantic relationship; and a selection unit for selecting, using the score acquired by the score acquisition unit, an expanded relationship information piece, which is a candidate expanded relationship information piece having a high score among candidate expanded relationship information pieces stored in the candidate expanded relationship information storage unit, wherein the score acquisition unit calculates a number of replacement which is performed to generate a same candidate expanded relationship information piece from relationship information pieces, and acquires a route score of the candidate expanded relationship information piece, and the route score takes a higher value as the number is higher, and wherein the score acquisition unit acquires a co-occurrence score that takes a higher score when the two or more language expressions included in the candidate expanded relationship information piece co-occur with a co-occurring language expression, which is a language expression having a high co-occurrence degree with two or more language expressions included in each relationship information piece having a semantic relationship of the same type as the semantic relationship of the relationship information piece used at the time of generation of the candidate expanded relationship information piece, than when only the two or more language expressions included in the candidate expanded relationship information piece co-occur with one another.
1. A relationship information expansion apparatus stored in a processor comprising: a relationship information storage unit in which a relationship information piece including two or more language expressions having a semantic relationship is stored; a similarity information storage unit in which two or more similarity information pieces each including two or more similar language expressions are stored; a candidate expanded relationship information storage unit in which a candidate expanded relationship information piece, which is the relationship information piece in which at least one language expression was replaced with a similar language expression, is stored; a candidate expanded relationship information generation unit for generating a candidate expanded relationship information piece from the relationship information piece stored in the relationship information storage unit by replacing at least one language expression in the relationship information piece with a language expression similar to the at least one language expression, using the similarity information pieces, and accumulating the candidate expanded relationship information piece in the candidate expanded relationship information storage unit; a score acquisition unit for acquiring a score that indicates a probability that the candidate expanded relationship information piece stored in the candidate expanded relationship information storage unit has a semantic relationship; and a selection unit for selecting, using the score acquired by the score acquisition unit, an expanded relationship information piece, which is a candidate expanded relationship information piece having a high score among candidate expanded relationship information pieces stored in the candidate expanded relationship information storage unit, wherein the score acquisition unit calculates a number of replacement which is performed to generate a same candidate expanded relationship information piece from relationship information pieces, and acquires a route score of the candidate expanded relationship information piece, and the route score takes a higher value as the number is higher, and wherein the score acquisition unit acquires a co-occurrence score that takes a higher score when the two or more language expressions included in the candidate expanded relationship information piece co-occur with a co-occurring language expression, which is a language expression having a high co-occurrence degree with two or more language expressions included in each relationship information piece having a semantic relationship of the same type as the semantic relationship of the relationship information piece used at the time of generation of the candidate expanded relationship information piece, than when only the two or more language expressions included in the candidate expanded relationship information piece co-occur with one another. 4. The relationship information expansion apparatus according to claim 1 , wherein the route score is a score that takes a higher value as the candidate expanded relationship information piece is obtained from more relationship information pieces, and takes a higher value as, in the replacement at the time of generation of the candidate expanded relationship information piece, the language expressions before the replacement and the language expression after the replacement are more similar to each other, and wherein a relationship information piece and a candidate expanded relationship information piece each includes two language expressions, which are a first language expression and a second language expression, the score acquisition unit acquires, for a candidate expanded relationship information piece, a route score, which is a value of an increasing function with an argument that is one or more arbitrary calculated values among a first calculated value, a second calculated value, and a third calculated value, the first calculated value being a sum of similarity degrees between the first language expression in each relationship information piece whose second language expression agrees with that in the candidate expanded relationship information piece and the first language expression in the candidate expanded relationship information piece, the second calculated value being a sum of similarity degrees between the second language expression in each relationship information piece whose first language expression agrees with that in the candidate expanded relationship information piece and the second language expression in the candidate expanded relationship information piece, and the third calculated value being a sum of products of similarity degrees between the first language expression in each relationship information piece stored in the relationship information storage unit and that in the candidate expanded relationship information piece and similarity degrees between the second language expression in each relationship information piece stored in the relationship information storage unit and that in the candidate expanded relationship information piece.