Delimiting the class of derived prepositions in Russian: Grammatical and semantic features of isključaja ‘excluding’ and vključaja, sčitaja ‘including’

The object of the article are Russian forms isključaja ‘excluding, except’, and vključaja, sčitaja, both meaning ‘including’, which are traditionally classified as derived prepositions. I demonstrate that these items have properties of both verbs (more precisely, adverbial participles) and prepositions. Still, it is necessary to attribute each item to a certain part of speech. To solve this problem, I use the principle of economy of linguistic description. I show that the description of the items under discussion is shorter and more adequate if we agree to regard them as adverbial participles (gerunds) used in the function of a preposition. I propose an analytic explication of meaning for each item and, besides that, explain why isključaja does not combine with an existential quantifier.