Today I read a paper titled “Relating Complexity to Practical Performance in Parsing with Wide-Coverage Unification Grammars”
The abstract is:
The paper demonstrates that exponential complexities with respect to grammar size and input length have little impact on the performance of three unification-based parsing algorithms, using a wide-coverage grammar.
The results imply that the study and optimisation of unification-based parsing must rely on empirical data until complexity theory can more accurately predict the practical behaviour of such parsers..