14. A non-transitory computer readable recording medium storing an ontology processing program which, when loaded into a memory and run by a computer, causes the computer to execute functions including: correcting a structure of ontology in a prescribed form created from a set of instance data containing a combination of a subject, a property, and an object expressed with a character string; judging whether each of the properties contained in the ontology is an essential property or an unessential property for a concept that is defined within the ontology and related to each of the properties according to statistical features of the objects contained in the set of instance data; correcting the structure of the ontology regarding the corresponding properties according to results of the judgments; and changing a property that is judged as unessential to a property having an inverted definition range and an inverted value range.
14. A non-transitory computer readable recording medium storing an ontology processing program which, when loaded into a memory and run by a computer, causes the computer to execute functions including: correcting a structure of ontology in a prescribed form created from a set of instance data containing a combination of a subject, a property, and an object expressed with a character string; judging whether each of the properties contained in the ontology is an essential property or an unessential property for a concept that is defined within the ontology and related to each of the properties according to statistical features of the objects contained in the set of instance data; correcting the structure of the ontology regarding the corresponding properties according to results of the judgments; and changing a property that is judged as unessential to a property having an inverted definition range and an inverted value range. 17. The non-transitory computer readable recording medium storing the ontology processing program as claimed in claim 14 , which enables the computer to execute: a function of judging whether or not, among the input data, a part of data showing a subject shows a specific concept, and determining a converting method of the part of data showing the subject based on a result of the judgment; a function of judging whether or not, among the input data, a part of data showing a property is an already-known property, and determining a converting method of the part of data showing the property based on a result of the judgment; a function of judging whether a part of data among the input data, which shows an object, is a literal or a resource, and determining a converting method of the part of data showing the object based on a result of the judgment; and a function of writing ontology in a prescribed form by using the result obtained by converting the data showing the subject, the property, and the object with the determined converting methods.