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. 2. The relationship information expansion apparatus according to claim 1 , wherein the relationship information piece also includes type identification information, which is information for identifying a type of the semantic relationship among the two or more language expressions included in the relationship information piece, the candidate expanded relationship information generation unit generates a candidate expanded relationship information piece including the type identification information included in the relationship information piece used to generate the candidate expanded relationship information piece, the relationship information expansion apparatus further comprises a correspondence information storage unit in which one or more correspondence information pieces each including the type identification information and one or more co-occurring languages expressions corresponding to the type identification information and corresponding to the type of the semantic relationship identified by the type identification information are stored, and the score acquisition unit acquires the co-occurrence score that takes a higher value when the two or more language expressions included in the candidate expanded relationship information piece co-occur with each co-occurring language expression corresponding to the type identification information included in 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.