Perhaps the triadic relation film / character / actor (and others things like "president of" from date, to date) could be solved by a software solution with reified statements.
Clicking reify would internally reify the statement. Perhaps this could be done by making a relation in the relation table with subject_title set to reified_statement and subject_id to mean reified statement nr.
Clicking add could bring up a form
Then typing in the relation "played by" "Melody Klaver" would make the statement ((Diep, has character, Heleen), played by, Melody Klaver). In this case (Diep, has character, Heleen) would be pretty much the same as a page "Heleen (Diep)" but would be more appropriate for less notable characters.
- Fuelbottle 13:29, 7 November 2006 (CET)
- Interesting. Then we would also need additional query possibilities to use this info.--Patrick 13:51, 7 November 2006 (CET)
- Yes, ask would need to recognize something like (subject,predicate,object) as an alternative to an article name. If this was used for a "president of" relation, perhaps something like <ask>(Bill Clinton, president of, United States of America) [[date from:=*]]</ask> could be used to display when Bill Clinton was inaugurated as president of the United States. - Fuelbottle 14:49, 7 November 2006 (CET)
- And also a query to find, from the date, the event, and perhaps with a nested query Bill clinton.--Patrick 15:00, 7 November 2006 (CET)
 Comment on the above
Reification of statements can be useful in some cases, but it also requires more complex syntax and semantics. I am not happy with introducing any new forms into Semantic MediaWiki for editing such relations, since this would change the user interface quite significantly, and since it seperates article content into several parts, not all of which can be accessed via normal editing.
Other than the issue with the more complex syntax in the wiki, the interpretation of reification also is not obvious. The RDF-way of semantically handling reification is disputed and not compatible with other Semantic Web languages such as OWL DL. OWL 1.1 will probably allow non-semantic annotations (comments) to be added to whole statements, and it is not clear whether this is going to be compatible with RDF at all. So it seems to be too early to include this into SMW.
But the examples I see above look to me like use cases for having structured datatypes or n-ary relations, rather than for annotating statements. E.g. the "president of" property basically links an article to one country and up to two dates. You would get quite a mess when annotating the statements "Clinton-President-USA" with a inauguration time, and then again annotating this statement with the time when his presidency ended. Imagine what chaos this style of chained reification will create in a wiki! Also, it is just not true to say that "Diep-Has character-Heleen" is played by Melody Klaver. If anything, then Heleen is played by Mrs. Klaver, not the statement. --Markus Krötzsch 07:22, 11 November 2006 (CET)