ملخص الجهاز:
"Polarity items in anti-additive contexts Van der Wouden(1988)argues that the property of anti-additivity is not only a determinant factor with respect to the behaviour of NPIs, but also that it is relevant for the distribution of PPIs. This opinion holds nicely for the class of PPIs in Dutch.
So, in agreement with the proposal made by Van der wouden with respect to the Dutch data, this set of expressions will be called PPIs of medium strength: (48 141)Definition: PPIs of medium strength are compatible with strictly downward monotonic contexts but incompatible with anti-additive ones.
Regarding the fact that the majority of negative polarity items in Persian are functioning as NPIs of medium strength, the conjecture that might be made here is that this language lacks any NPI whose appearance is ungrammatical in anti-additives.
Given the fact that the licensing environments for polarity elements in Persian turn out to be disjoint, we have devoted our discussion in the second chapter to that a classification of negative contexts is indeed fruitful to explaining this distributional diversities for both classes of NPIs and PPIs. Although, any theory which handles all members of negative and positive polarity items with a single set of principles is more economical and desirable that one which must distinguish between subclasses and set up separate rules for each subclass, the facts presented here provide us with strong evidence against a unified treatment of PSIs with respect to their distributional varieties."