AbstractThis thesis investigates the mathematical foundations that are necessary for an extension of Abramsky's domain theory in logical form to continuous domains.We present a multi-lingual sequent calculus, that is a positive logic allowing sequents that relate propositions from different languages. This setup necessitates a number of syntactic adjustments. In particular, we discuss different reformulations of the cut rule and how they can be used as a basis for a category MLS of logical systems. Then we investigate cut elimination in this logic. From a semantic point of view this can be seen as enabling us to perform domain constructions in purely syntactic form.The category MLS has a number of different manifestations, and we study it w...