Syntax experiments

Various experiments with syntax analysers splitted among different branches.

I. Ablation experiments

Investigations on the impact of training set size, morphological features and clausal patterns on syntactic parsing; experiments with parsing model ensembles; automatic evaluation and investigation of parsing errors

Branch: ablation_experiments

II. Syntax consistency

Search for sentence level modifications that preserve syntax. In theory, syntax should be conserved when free entities are removed from sentences. Sometimes this is also true for bound entities such as objects. In practice, additional factors, such as interpunctuation and wording consistency, have a big inpact on the outcomes.

The branch contains workflows for shortening sentences and preparing the results for manual labelling followed by small analysis of the results. Experiments are done for different phrase types where each phrase type is defined by the dependency relation predicted by stanza syntax analyser.

Branch: syntax_consistency

III. Consistency between adverbial phrases and named entities

Adverbial phrases often coincide with geographical location or time expression, but not always. In these experiments, we study this problem in detail. For that we use a stanza syntax analyzer to extract adverbials and dedicated taggers for isolating named entities and time expressions. After that we build a workflow for extracting sentences where these annaotations are in potential conflict and extract corresponding sentences for manual labelling.

Branch: adverbials

IV. Subcategorisation and argument structure

Statistical methods for extracting information about subcategorisation of verbs using only automatically generated syntax for a large text corpus. Subcategorization for verbs is defined by argument structure that specifies a list of selected arguments associated with specific lexical restrictions. For Estonian, these restrictions are defined in terms of plausible cases. It is imporant to note that not all arguments in the argument structure are mandatory and that the same verb can have more than one argument structure.

Still it possible to use law of large numbers to extract important information about argument structure. For that, we tabulate syntax level collocations between verb phrases and noun phrases defined through obl dependency relation.

Branch: subcat

V. Semantic labelling

Semantical categorisation based on the arguments structure. Verbs place semantic restrictions on their arguments. This can be exploited to categorise nouns into sementic categories and the other way around -- find whether a particular argument of a verb must satisfy certain restrictions.

Branch: semantic_labelling

VI. Outdated experiments

Contains code of legacy experiments that are no longer supported

Branch: legacy