My research in theoretical syntax is informed by the tradition of generative grammar pioneered by Noam Chomsky in the late fifties, which assumes the existence of an innate language faculty, distinct from (but interfacing with) other cognitive systems. On a theoretical level, my research on multidominance (the kinds of syntactic structures which allow a single alement to occupy two positions simultaneoulsy) and phases (self-contained syntactic chunks) contributes to our understanding of the structure building mechanisms and the constraints these mechanims are subject to. On an empirical level, my research contributes to our understanding of various types of wh-constructions in natural language, such as free relatives (e.g. John eats whatever Bill cooks), Across-the-board wh-questions (e.g. What did John eat and Bill cook? and wh-questions with coordinated wh-pronouns (e.g. What and where does John eat?). My research on the syntax of Polish contributes to our understanding of the syntax of Slavic languages and, more generally, to our understanding of which aspects of language are universal and which ones are subject to crosslinguistic variation.