Rootedness, connectedness and unique parenthood
Rootedness - there is exactly one word W for which the following two statements are both true:
- W is the source of at least one dependency
- W is not the target of any dependency
Connectedness - every word is either the source or target of some dependency
Unique parenthood - every word which is the target of some dependency, is the target of just the one dependency
Rootedness, connectedness and unique parenthood are all independent
Rooted + connected + unique parent
John thinks that Mary rocks
(thinks,John)
(thinks,that)
(that,rocks)
(rocks,Mary)
Rooted + connected + non-unique parent
John thinks that Mary rocks
(thinks,John)
(thinks,that)
(that,rocks)
(rocks,Mary)
(thinks,rocks)
Rooted + non-connected + unique parent
John thinks that Mary rocks
(thinks,John)
(thinks,rocks)
(rocks,Mary)
Rooted + non-connected + non-unique parent
John thinks that Mary rocks
(thinks,John)
(thinks,rocks)
(rocks,Mary)
(thinks,Mary)
Non-rooted + connected + unique parent
John thinks that Mary rocks
(thinks,John)
(that,rocks)
(rocks,Mary)
Non-rooted + connected + non-unique parent
John thinks that Mary rocks
(thinks,John)
(that,Mary)
(rocks,Mary)
Non-rooted + non-connected + unique parent
John thinks that Mary rocks
(thinks,John)
(rocks,Mary)
Non-rooted + non-connected + non-unique parent
John thinks that Mary rocks
(thinks,John)
(rocks,Mary)
(thinks,Mary)
Acyclicity
If there is a sequence of dependencies from word W1 to word W2, then there is no sequence of dependencies from W2 to W1.
Others
Functionality - for each word W and each dependency label T, there is no more than one dependency from W labelled with T
--
MarkMcConville - 14 Aug 2008