The semantic relations between verbs used for the implementation in
GermaNet differ from those in WordNet in several respects:
We allow for the causation relation between verbs and adjectives
as well, in order to account for the fact that causative verbs systematically
relate a verb to its resultative state (zerschleißen (destroying by wearing out)
causes something to be zerstört (destroyed)).
We try to use the entailment relation only when the semantics of the verb
suggests this very strongly, that is we pay attention not to encode entailment if
only one aspect of the verb supports an entailment relation (e.g. bekommen (ein Kind)
Up to now, we have made little use of the association relation, which is a vage
pointer to a concept which is related in a not further specified way (e.g. Schließvorrichtung
is associated with schließen).
The approach taken in GermaNet differs explicitly form WordNet in that
it makes extensive use of cross-classification. This leads to a much denser wordnet. Furthermore, it allows a classification of concepts according
to different semantic criteria. For example, verbs involving change of location
can be classified according to whether they specify
the activity of an agent/theme/group and at the same time according to transitivity/intransitivity and specification of a particular direction.
In contrast to nouns and adjectives, verbs in GermaNet provide information on their actual language use by giving at least one example sentence per lexical unit.
In order to link lexical semantic and syntactic information, details on syntactic
subcategorisation are indicated for each lexical item.
This information can be used to distinguish between different readings of
ambiguous verbs. These different readings can be related to distinct frames, providing useful
information for disambiguation of verbs in textual contexts. Thus, frames denote subcategorisation
patterns for verbs.
Note that the subcategorisation frames for verbs provide additional
information for the discrimination of a verb's senses.
ausgehen(1): Wir gehen heute abend aus. Frame: NN
ausgehen(2): Er ging von seiner Unschuld aus. Frame: NN.PP
ausgehen(3): Die Geschichte ging gut aus. Frame: NN.BM
The frames used in GermaNet are based on the Complementation Codes provided
with the German Version 2.5 of Release 2 of the CELEX Lexical database (1995). The notation
in GermaNet differs from what is given in the CELEX database in that it provides an easily
readable compact notation including a notation for the subject. Additionally, a complementation
code for obligatory reflexive phrases has been added, abbreviated by "R". Note that
GermaNet provides frames for verb senses, rather than for base forms (lemmas). This implies a
full disambiguation of CELEX Complementation Codes for GermaNet. For further details, see the
information on Verb Frames.
Currently, the GermaNet verb classification follows the WordNet classes
in the top categories. However, within a class the structure of the wordnet
deviates widely from WordNet. The classification follows
Levin (1993) wherever possible. Even though
some English verb classes are different from German ones in various points, the classes
are still amazingly parallel. For details about the different classes see the information on
Verb Classes in GermaNet.