So What about Published Subject Indicators?

The above example, in the form of Sarah's reference to Grandfather, seems to yield at first sight an exact natural language equivalent of what Published Subject Indicators (PSIs) are about in the topic maps paradigm and of how they are built (through both acknowledged authority and the permanence of the authority's location). A PSI in the XTM 1.0 specification ( is defined as follows:

A subject indicator is a resource that is intended by the topic map author to provide a positive, unambiguous indication of the identity of a subject [emphasis added].

A published subject is any subject for which a subject indicator has been made available for public use and is accessible ...

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