Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
A note on the implementation.
Although the basic idea behind this treatment of head movement is very simple, it is now a bigger job to
take care of all the details in parsing. There are many more special cases of merge and move. Prolog does
not like all the operators we are using to indicate the different kinds of selection we have, so unfortunately we
need a slightly different notation there. The whole collection so far is this:
feature meaning prolog notation
x category x x
=x select and merge with a phrase with category x =x
(first selection attached as comp, on right, second as spec, on left)
+x move a phrase with feature -x to spec +x
-x move to the spec of a category with a +x feature -x
=>x select phrase with cat x and adjoin its head on the left of yours =>x
x