Sameness
When are to objects the same object?
Is a hardback book the same as the
paperback? Is a postscript version
of a paper the "same" as a plain
ASCII text version? Is the 1994
edition the same as the 1988 edition?
Different systems have very different
ideas of what "sameness" of objects
implies. This is because a given
document may exist in different "variants",
such as:
- Translations into different languages
- Representation at different resolutions
- Reformatting in a different style
- Updating to a new version
- Republication by a different company
- Annotation
There is no simpllistic answer to
thi question, as for different purposes
it is useful to consider variants
to be the same or different. Thherefore,
in WWW, we generalize the concept
of an "object" to be a more or les
generic object as required. For
example, one name may identify a
specific version of a document, and
another the generic document in any
verson, translation, or rendering.
The HTTP protocol allows the metainformation
relating these objects to be communicated.
It allows a name to be given along
with information about what sorts
of variants (if any) are allowed
within the generic object as named.
(Up to requirements, on to xxx)
Tim BL