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arXiv 1604.08709cs.AIcs.LO
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作为正常模态逻辑的“知值”逻辑

"Knowing value" logic as a normal modal logic

Peking University(北京大学)

Tao Gu, Yanjing Wang

摘要:

近年来,人们对“知道是否”、“知道什么”、“知道如何”等非标准认知逻辑的兴趣越来越大。这些逻辑通常是非正规的,即,模态逻辑的标准公理和推理规则可能是无效的。本文证明了Wang和Fan \cite{WF13}提出的条件“知值”逻辑可以被看作是一种伪装的正常模态逻辑,方法是把Kv算子的否定看作一种特殊的菱形。在这种观点下,原来的一阶Kripke语义可以通过在标准Kripke模型中引入三元关系$R_i^c$来大大简化,该三元关系将一个世界与两个$i$可访问的世界相关联,这两个世界在常量$c$的值上不一致。在直觉约束下,基于这种Kripke模型的模态逻辑正是Wang和Fan(2013,2014)所研究的模态逻辑。此外,有一个非常自然的二进制推广的“知道值”钻石,这令人惊讶的是,并没有增加逻辑的表达能力。由此得到的二进制菱形逻辑具有透明的正规模态系统,这加深了我们对“知值”逻辑的理解,并简化了一些以前难以解决的问题。

英文摘要:

Recent years witness a growing interest in nonstandard epistemic logics of "knowing whether", "knowing what", "knowing how", and so on. These logics are usually not normal, i.e., the standard axioms and reasoning rules for modal logic may be invalid. In this paper, we show that the conditional "knowing value" logic proposed by Wang and Fan \cite{WF13} can be viewed as a disguised normal modal logic by treating the negation of the Kv operator as a special diamond. Under this perspective, it turns out that the original first-order Kripke semantics can be greatly simplified by introducing a ternary relation $R_i^c$ in standard Kripke models, which associates one world with two $i$-accessible worlds that do not agree on the value of constant $c$. Under intuitive constraints, the modal logic based on such Kripke models is exactly the one studied by Wang and Fan (2013,2014}. Moreover, there is a very natural binary generalization of the "knowing value" diamond, which, surprisingly, does not increase the expressive power of the logic. The resulting logic with the binary diamond has a transparent normal modal system, which sharpens our understanding of the "knowing value" logic and simplifies some previously hard problems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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