Monadic datalog and the expressive power of languages for Web information extraction.

Research on information extraction from Web pages (wrapping) has seen much activity recently (particularly systems implementations), but little work has been done on formally studying the expressiveness of the formalisms proposed or on the theoretical foundations of wrapping. In this paper, we first...

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Xuất bản năm:	Journal of the ACM 51, 1 (2004).
Tác giả chính:	Gottlob, Georg
Định dạng:	Bài viết
Ngôn ngữ:	English
Những chủ đề:	Theory of computation. Computation by abstract devices. Models of computation. Automata (e.g., finite, push-down, resource-bounded). Mathematical logic and formal languages. Mathematical logic. Computational logic. Formal languages. Classes defined by grammars or automata (e.g., context-free languages, regular sets, recursive sets). Information systems. Database management. Languages. Theory.