The distribution of the patterns of nasal-consonant clusters in Catalan has been attributed in the literature to the application of Nasal Assimilation, which correlates with Cluster Simplification. However, the absense of several clusters in this language cannot be accounted for with this kind of analysis. In this paper, I propose that these clusters are absent not only in the output but in the input as well due to several constraints which apply to underlying forms. Furthermore, I will discuss whether the conclusion drawn here poses a problem for Optimality Theory, where it is assumed that inputs are not restricted in any way.
