PERSISTENT IDENTIFIERS:WHAT IF?

17/19 – Uniqueness environment

"A PID is a label associated with something in a particular environment.
On the Internet it should be globally unique, but it may only be so within a specified context. At any rate, it must be unique within the institution's own system."
"Oohhh, what a masterpiece!"
Uniqueness environment
A PID is label that is associated with something in a particular environment.
On the Internet it should be globally unique, but may only be unique in combination with a limited name space. In the 'worse' case it may only be unique within an organisation's own systems.

Therefore:
Organisations should be clear, and make public, in which environment their PIDs are unique. Persistent Identifiers (PIDs): recommendations for institutions (PDF) by Gordon McKenna and Roxanne Wyns.