Some Interdefinability Results for Syntactic Constraint Classes

Choosing as my vantage point the linguistically motivated Müller-Sternefeld hierarchy [23], which classifies constraints according to their locality properties, I investigate the interplay of various syntactic constraint classes on a formal level. For non-comparative constraints, I use Rogers’s framework of multi-dimensional trees [31] to state Müller and Sternefeld’s definitions in general yet rigorous terms that are compatible with a wide range of syntactic theories, and I formulate conditions under which distinct non-comparative constraints are equivalent. Comparative constraints, on the other hand, are shown to be best understood in terms of optimality systems [5]. From this I derive that some of them are reducible to non-comparative constraints. The results jointly vindicate a broadly construed version of the Müller-Sternefeld hierarchy, yet they also support a refined picture of constraint interaction that has profound repercussions for both the study of locality phenomena in natural language and how the complexity of linguistic proposals is to be assessed.