-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Am 11.07.2014 23:49, schrieb Denenberg, Ray: > · I agree with Jeff Young who said (if it really was Jeff – hard to tell) > ‘ The abandoned "info" URI effort leaves me skeptical that non-HTTP URIs can be systematically described in general.’ > (This is a battle that I fought for years, but I long ago accepted defeat.) And I honestly think we should treat isbn, issn, etc. – even fully formulated URNs – as string identifiers and not try to turn these into actionable URIs. Perhaps with emphasis on "we". To give two examples: The Gemeinsame Normdatei (GND) of the German National Library clearly has identifiers. To many of us they are known as in the form of the example string "123799465". However, in the MARC community they are known as "(DE-588)123799465". The DNB Website and MARC21 representations of the authority record state as "other standard identifier" some "http://d-nb.info/gnd/123799465" either to be considered as a "weblink" or as an identifier sourced from some "uri" identifier system. Following Ray's comment maybe we have outwitted ourselves by "knowing" that <http://d-nb.info/gnd/123799465> is the URI for the identifier "123799465" and anyhow "(DE-588)" and "http://d-nb.info/gnd/" are just some namespacey way to identify the identifier system for the real identifier following these prefixes. Maybe all three forms just are string representations for some abstract GND identifier of the resource: Equivalent with respect to the resource they are identifying and distinct when it comes to different contexts where their use is encouraged or not permissible: * "(DE-588)123799465" is mandatory in MARC contexts * "http://d-nb.info/gnd/123799465" is the string representation for the /official/ URI <http://d-nb.info/gnd/123799465> * "http://d-nb.info/gnd/123799465" is the string representation for an officialy provided actionable URI / URL <http://d-nb.info/gnd/123799465> The important point is, these equivalences, transformations and interpretations are properties of that particular identifier system and their validity is declared, guaranteed and technically maintained by some body (DNB) responsible for "operating" this identifier system. This body issues statements that identifiers like "123799465" and "http://d-nb.info/gnd/123799465" pertain to the same resource, may be turned into actionable URLs and how this can be done. (One might argue that the equivalence of "123799465" and "(DE-588)123799465" is a statement issued by LC in its role as the MARC standards body and there especially as maintainer of the list of organizational codes. Or - since these codes are defined as to be ISILs - a joint statement of LC and the ISIL agency maintaining "DE-588" as identifier for the GND as such) [Note that the "prefix URI" < http://d-nb.info/gnd/ > is not web actionable and there is no evidence that this URI was ever used to identify the GND as a database or web application, or the dataset of all concepts covered by individual GND records, nor the set of all GND identifiers emitted so far or the space of all possible GND identifiers or GND URIs] Now GND and VIAF are some of the few identifier systems which provide us with official URIs and actionable URLs at all. Many more systems do not have these properties, even quite recent ones like ISIL or ISNI. Consider ISBNs as another example: * There is the "old" form "1-59158-509-0" of an ISBN and the "new" (EAN) form "978-1-59158-509-1" (I've choosen a publication from 2007 for my example to avoid discussions that one should be preferred over the other). * If I recall correctly the ISBN agency states that ISBNs shall be used (imprinted) with dashes and a prefix "ISBN" followed by a space: "ISBN 1-59158-509-0" rsp. "ISBN 978-1-59158-509-1" * And the forms "1 59158 509 0" and "978 1 59158 509 1" commonly printed by US publishers into the resource. * Not to forget the forms "1591585090" and "9781591585091" as recorded in 020$a of MARC21 records. * And there are URN:ISBN:1-59158-509-0 by RFC 3187 and info:isbn/1591585090 from the "info" URI scheme/registry To my knowledge none of the two approaches ever has been acknowledged or endorsed by the ISBN agency All these strings are equivalent identifiers when considered /as/ ISBN but again in different usage contexts only certain representations are allowed: MARC21 does not allow to record "ISBN 978-1-59158-509-1" in field 020 although the ISBN agency declares this as /the/ official form. In this situation we have many communities issuing equivalence statements for string representations of "abstract" ISBNs: - - the agency (ISBN-10 <-> ISBN-13 transformation of the dashed forms) - - (some) librarians (MARC21 form) - - (some) publishers ("blanked" forms) - - ??? (ubiquitous eqivalence of ...-x and ...-X) - - IETF (URN:ISBN scheme) - - OCLC (info:isbn scheme) ... I don't think bibframe will ever be able to enforce the usage of one of these representation styles as preferred over all of the others - even the ISBN agency had not been able to enforce the official form. And it will not desirable to always supply the complete zoo of equivalent strings for every resource. Thus there will be systems (as there are people) which will not be able to detect that the identifier strings presented by two ressources are equivalent within the ISBN context and actually represent the same (abstract) ISBN. And neither bibframe itself nor the kind of reasoning or deference currently available in the semantic web will be able to remedy that. To conclude: - - Many of our favourite identifiers are and will remain strings - - since not all of these strings are URIs we'll have to indicate what identifier system the belong to (bibframe might provide a registry providing URIs for the identifier systems in a vocabulary-like manner) - - Also strings which look like URIs should be acoompanied by information to which identifier system they are to be associated - when used as identifiers: Distilling a common prefix from uniformly build URIs is not a permitted operation /and/ we would not know wether the thus extracted URI "URN:ISBN:" should represent the ISBN identifier system as such or the Dataset of all ressources identified by ISBNs (and we propbably cannot afford to neglect that distinction) - - Most of our identifier systems have specific and non-trivial equivalence rules for the strings (considering them to be opaque as demanded for URIs won't be of any help) often reflecting common usage in different communities. Not even the maintainers of the identifier systems will have knowledge about all of these convenience forms, let alone bibframe. viele Gruesse Thomas Berger -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iJwEAQECAAYFAlPAkBoACgkQYhMlmJ6W47P+tQP9FdAIdJMFO7Nfh2ralSmpVfx5 8rBl5sScdPGvwpRgKbQS52Q8GlUl6LFKBb4opl5zpcl2+tXT2Va3+DRnVvZoEuXF kR/pWz7rQnM0lPzvxwEk0kOOOSH+T4ZnfO4t/RKZLdFq1XZWfab4Y0CmoprYLjSs qxvbOsKcNVn+134v8zU= =cgb1 -----END PGP SIGNATURE-----