Bry, FrançoisPătrânjan, Paula-LaviniaSchaffert, SebastianDadam, PeterReichert, Manfred2019-10-112019-10-1120043-88579-380-6https://dl.gi.de/handle/20.500.12116/28699In this article, two deductive languages are introduced: the language Xcerpt, for querying data and reasoning with data on the (Semantic) Web, and the language XChange, for evolution and reactivity on the (Semantic) Web. A small application scenario is given as a motivation for these languages.enXcerpt and Xchange: Deductive languages for data retrieval and evolution on the webText/Conference Paper1617-5468