content and carrier

[kcoyle]

We had a discussion about adding some text to the primer about content (Work and Expression) and carrier (Manifestation and Item). Here is some suggested text:

The four elements of WEMI represent both the conceptual content of creations as well as their realization in tangible forms (also known by the respective terms "content" and "carrier"). Generally speaking, the intellectual content of an Endeavor is described through Work and Expression, and the realization or carrier of the Endeavor is described through Manifestation and Item. How specific descriptive properties are distributed within the WEMI stack will vary in implementations of vocabularies that make use of the WEMI concepts. More expansively:

• Work: an abstraction that can be used to describe the intellectual content of an Endeavor that may include descriptions of subject matter, the responsible agents, and other pertinent or identifying information appropriate to the abstraction.
• Expression: an expression is also an abstraction relating to the intellectual content; it can be used to describe the method by which the endeavor is articulated for understanding or reception. Some examples are: text, sound, photograph, visual work, verbal communication; but also more specific terms needed by the vocabulary such as bas-relief, batik print.
• Manifestation: Manifestation can be used to describe the carrier or vehicle in which the Endeavor is realized; manifestations may be physically tangible or digital. Examples are: books, PDF files, toys. Manifestation are often, but not always, produced in multiples.
• Item: Item is a tangible realization of an endeavor, and is generally considered to have a discernable location. A single copy of a published article and the automobiles with a specific identification number are examples of Items.

[kcoyle]

As an FYI, LRMoo has this, which is a bit like content and carrier, but also significantly different:

Work
    subclass of Propositional Object
Expression
    subclass of Informational Object
Manifestation
    subclass of informational Object
Item
    subclass of Physical Human-Made Thing

This places Work alone as an abstraction, with Expression and Manifestation having informational rules, and item being concrete. (The "human-made" is a restriction, IMO. It makes it impossible to describe the output of programs, creations by bots or AI, and of course paintings done by apes and elephants.)

"Propositional object" is defined as "This class comprises associations between an instance of any class, and signs or arrangements of signs that are used to refer to and identify that instance."

Propositional objects have an identity but no substance. I note that we have not defined Endeavor as an identified entity.

[philbarker]

I like the suggested text a lot, I think it is very clear and informative. One minor change I would suggest, for

Manifestation: Manifestation can be used to describe the carrier or vehicle in which the Endeavor is realized; manifestations may be physically tangible or digital. Examples are: books, PDF files, toys. Manifestation are often, but not always, produced in multiples.

I would prefer the example to be "editions of books" in order to avoid confusion over whether a physical book is meant.

I also think the last sentence in that bullet could be misinterpreted as meaning that multiples of the manifestation itself are available, so how about "Often, but not always, multiple physical copies instantiating the same manifestation are available."