| 摘要 |
PROBLEM TO BE SOLVED: To provide information for retrieval profitable in a transaction for a user even if the user specifies multiple keywords as a searching option.SOLUTION: A retrieval device divides multiple keywords specified as searching options into two subsidiary searching options including the keywords. The retrieval device searches for a retrieval object matching all of the multiple keywords as the searching option. In addition, the retrieval device searches for a retrieval object matching all of the keywords included in one of the subsidiary searching options and a retrieval object matching all of the keywords included in another subsidiary searching option. The retrieval device extracts a combination of retrieval objects having a relation from combinations of any one of retrieval objects retrieved with one of the subsidiary searching options and any one of retrieval objects retrieved with another subsidiary searching option. The retrieval device determines a combination more advantageous to a user in a transaction than the retrieval object retrieved with the specified searching option. The retrieval device provides the determined combinatorial information. |
