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# An example from Wikipedia, particularly …
# An example from Wikipedia, particularly http://en.wikipedia.org/wiki/Relation_(mathematics) : <blockquote>An example of a ternary or triadic relation (i.e., between three individuals) is: "X was-introduced-to Y by Z", where (X,Y,Z) is a 3-tuple of persons; for example, "Beatrice Wood was-introduced-to Henri-Pierre Roché by Marcel Duchamp" is true, while "Karl Marx was-introduced-to Friedrich Engels by Queen Victoria" is false.</blockquote> This (somewhat contrived) relation could be represented using a relational database. It would be a "relationship relation", and each row would store an X, a Y, and a Z. In order to represent this relationship using a triple based model, it is necessary to introduce some sort of "introducing event" objects which correspond to the rows of the table, and which would be the domain of three properties, say, introduction_event:person1, introduction_event:person2, and introduction_event:introducer. A similar thing has to happen if the database contains a '''Person''' table with three attributes, ''name'', ''birthdate'', and ''gender''; the difference is that it does not seem strange to us to introduce '''Person''' objects—they're just people.
# The authors are using this example to show how the ''validation process'' would eliminate an inconsistent mapping. (Their language is a bit unclear, though.) Presumably the mapping between ''hasID'' and ''id'' would be discovered based on the results of ''Des(hasID)'' and ''Des(id)''. Though in this example "hasID" and "id" are distinct tokens, they might, in reality, have some more complex descriptions which have some similarity. If this ''isn't'' the case, it is hard to imagine the authors' system overcoming ''any'' lexical differences in terminologies that arise between databases and ontologies.
# Immediately below '''ContextMatch'', the authors write "In lines 6–8, the algorithm repeatedly examines each attribute in the relation ((to determine)) whether it is a categorical attribute or not." Based on the way that they ''use'' the categorical attributes, a categorical attribute is one in which a partitioning of instances based on their attribute values corresponds to some partitioning of the disjoint subclasses of the class at hand. disjoint subclasses of the class at hand.
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