Editing Identifier (section)

==Ambiguity==
===Identifiers (IDs) versus Unique identifiers (UIDs)===
{{Main|Unique identifier}}
A resource may carry multiple identifiers. Typical examples are:
* One person with multiple names, nicknames, and forms of address (titles, salutations)
** ''For example:'' One specific person may be identified by all of the following identifiers: Jane&nbsp;Smith; Jane&nbsp;Elizabeth&nbsp;Meredith&nbsp;Smith; Jane&nbsp;E.&nbsp;M.&nbsp;Smith; Jane&nbsp;E.&nbsp;Smith; Janie&nbsp;Smith; Janie; Little&nbsp;Janie (as opposed to her mother or sister or cousin, Big&nbsp;Janie); Aunt&nbsp;Jane; Auntie&nbsp;Janie; Mom; Grandmom; Nana; Kelly's&nbsp;mother; Billy's&nbsp;grandmother; Ms.&nbsp;Smith; Dr.&nbsp;Smith; Jane&nbsp;E.&nbsp;Smith,&nbsp;PhD; and Fuzzy (her jocular nickname at work).
* One document with multiple versions<ref name=paid>{{cite web
  | last = University of Glasgow
  | author-link = University of Glasgow
  | title = Procedure for Applying Identifiers to Documents
  | url = http://www.gla.ac.uk/infostrat/ERM/Docs/procref.htm
  | access-date = 28 April 2009
  | archive-url = https://web.archive.org/web/20110605081415/http://www.gla.ac.uk/infostrat/ERM/Docs/procref.htm
  | archive-date = 5 June 2011
  | url-status = dead
  }}</ref>
* One substance with multiple names (for example, [[Chemical Abstracts Service|CAS]] index names versus [[IUPAC]] names;<ref name=icn>{{cite web
  | last = University of Pennsylvania
  | author-link = University of Pennsylvania
  | title = Information on Chemical Nomenclature
  | url = http://gethelp.library.upenn.edu/guides/scitech/chemnom.html
  | access-date = 28 April 2009
  | archive-date = 4 January 2009
  | archive-url = https://web.archive.org/web/20090104023819/http://gethelp.library.upenn.edu/guides/scitech/chemnom.html
  | url-status = dead
  }}</ref> [[International Nonproprietary Name|INN]] generic drug names versus [[United States Adopted Name|USAN]] generic drug names versus brand names)

The inverse is also possible, where multiple resources are represented with the same identifier (discussed below).

===Implicit context and namespace conflicts===
{{see also|Naming collision}}
Many [[code]]s and [[nomenclature|nomenclatural]] systems originate within a small [[namespace]]. Over the years, some of them bleed into larger namespaces (as people interact in ways they formerly had not, e.g., cross-border trade, scientific collaboration, military alliance, and general cultural interconnection or assimilation). When such dissemination happens, the limitations of the original naming convention, which had formerly been latent and moot, become painfully apparent, often necessitating [[retronym]]y, [[synonym]]ity,
translation/[[transcoding]], and so on. Such limitations generally accompany the shift away from the original context to the broader one. Typically the system shows implicit context (context was formerly assumed, and narrow), lack of capacity (e.g., low number  of possible IDs, reflecting the outmoded narrow context), lack of [[extensibility]] (no features defined and reserved against future needs), and lack of specificity and disambiguating capability (related to the context shift, where longstanding uniqueness encounters novel nonuniqueness). Within computer science, this problem is called [[naming collision]]. The story of the origination and expansion of the [[CODEN]] system provides a good case example in a recent-decades, technical-nomenclature context. The capitalization variations seen with [[proper noun#Specific designators|specific designators]] reveals an instance of this problem occurring in [[natural language]]s, where the proper&nbsp;noun/common&nbsp;noun distinction (and its complications) must be dealt with. A universe in which every object had a UID would not need any namespaces, which is to say that it would constitute one gigantic namespace; but human minds could never keep track of, or semantically interrelate, so many UIDs.