A Theoretical Basis of an Architecture of a Shell of a Reasonably Robust Syntactic Analyser

Abstract

This paper describes the theoretical basis of a framework for syntactic analysis allowing for flexible, stepwise shifting of the separation line between two sets of ill-formed strings which, given a fixed degree of robustness, i.e. tolerable violation of grammatical constraints:

• either still are assigned a syntactic structure by a robust syntactic analyser

• or are corrupted so heavily (wrt. the degree of robustness) that no structure can be assigned.

An important feature of the framework is that it both allows for and is based on explicit measuring of the degree of robustness needed for analysing a certain input string. This provides for creating a scale of robust syntactic analysers with stepwise increasing coverage of ill-formed input (e.g., in dependence on the intended application), all based on the same initial grammar.

The first and the third author were supported by the Grant Agency of the Czech Republic, Grant-No. 201/02/1456. The work by Karel Oliva has been sponsored by the Fonds zur Förderung der wissenschaftlichen Forschung (FWF), Grant No. P12920. The Austrian Research Institute for Artificial Intelligence (ÖFAI) is supported by the Austrian Federal Ministry of Education, Science and Culture.