This paper is part of a larger study that aims to create the first quantitative grammar of the Russian prepositional system. The present study deals with Russian secondary multiword prepositions. Prepositions are a heterogeneous class consisting of a small group of about 25 primary prepositions and hundreds of secondary ones, the latter being motivated by content words (nouns, adverbs, verbs), which may be combined with primary prepositions to form multiword prepositions (MWPs). A strict division between secondary multiword prepositions and equivalent free word combinations is not specified. This is a task for a special corpus-based research.
Prepositions are characterized as function words used to express various relationships between main and dependent members of a phrase. The difficulty is that relations expressed by prepositions are multi-sided, grammatical and lexical. Primary prepositions are said to have no real lexical meaning. It is not quite true as regards primary prepositions and even more so for secondary ones. Prepositions express semantic relations between words, and their meanings directly correspond to these relations. Multiword prepositions perform the grammatical function of a preposition in a certain position of a syntactic structure in some contexts and can be a free combination in others. This paper is devoted to the statistical analysis of the use of multiword prepositions in corpora. The features of multiword prepositions in the function of a preposition are described. Statistical data on the ratio of the use of individual multiword expressions as prepositional units and as free combinations are provided.