[Semantic Web]Reasons for the Popularity and Importance of Logic

读书笔记 Lee 发表于 2006/3/4 12:07:08 • It provides a high-level language in which knowledge can be expressed in a transparent way. And it has a high expressive power. • It has a well-understood formal semantics, which assigns an unambiguous meaning to logical statements. • There is precise notion of logical consequence, which determines whether a statement follows semantically from a set of other statements (premises). In fact, the primary original motivation of logic was the study of objective laws of logical consequence. • There exist proof systems that can automatically derive statements syntactically from a set of premises. • There exist proof systems for which semantic logical consequence coincides with syntactic derivation within the proof system. Proof systems should be sound (all derived statements follow semantically from the premises) and complete (all logical consequences of the premises can be derived in the proof system). • Predicate logic is unique in the sense that sound and complete proof systems do exist. More expressive logics (higher-order logics) do not have such proof systems. • Because of the existence of proof systems, it is possible to trace the proof that leads to a logical consequence. In this sense, the logic can provide explanations for answers.

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