Referred to a related thing: description logics again.

diff --git a/doc/todo/pagespec_relative_to_a_target.mdwn b/doc/todo/pagespec_relative_to_a_target.mdwn
index 4757988e0a27b0b7cdcb8fa23978f151cc1bbad4..00030cce61093192797a46a545389c324cf46078 100644 (file)
--- a/doc/todo/pagespec_relative_to_a_target.mdwn
+++ b/doc/todo/pagespec_relative_to_a_target.mdwn
@@ -90,8 +90,12 @@ diff -urNX ignorepats ikiwiki/IkiWiki/Plugin/relative.pm ikidev/IkiWiki/Plugin/r
 
 [[!tag patch]]
 
-> This looks really interesting.  It reminds me of XPath and its conditionals.
+> This looks really interesting.  It reminds me of [[!wikipedia XPath]] and its conditionals.
 > Those might actually work well adapted to pagespecs.  For instance, to write
 > "match any page with a child blah", you could just write *[blah] , or if you
 > don't want to use relative-by-default in the conditionals, *[./blah].
 > -- [[JoshTriplett]]
+
+> And it [[!taglink also_reminds_me|pagespec_in_DL_style]] of [[!wikipedia description logics]]: of course, given the relation `subpage` one could write a description-logic-style formula which would define the class of pages that are ("existentially") in a given relation (`subpage` or `inverse(subpage)*subpage`) to a certain other class of pages (e.g., named "blah") ("existentially" means there must exist a page, e.g., named "blah", which is in the given relation to the candidate).
+
+> Probably the model behind XPath is similar (although I don't know enough to say this definitely).--Ivan Z.