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arXiv cs/0202018cs.AIcs.LOmath.LO
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非单调逻辑与语义

Nonmonotonic Logics and Semantics

Daniel Lehmann

摘要:

塔斯基给出了演绎推理的一般语义:一个公式a可以从一组公式A中推导出来,当且仅当a在所有模型中成立,其中A的每个元素都成立。一个更自由的语义被认为是:公式a可以从一组公式A中推导出来,当且仅当a在所有的“偏好”模型中成立,其中A的所有元素都成立。Shoham提出“首选”模型的概念可以通过底层语言模型的部分排序来定义。本文描述了一个更一般的语义,基于一组自然属性的选择功能。这种语义在这里被证明是等价于语义的基础上比较的相对“重要性”的模型集,由什么金额的定性概率测量。等价语义定义的结果操作的特点,然后由Tarski的性质,其中的单调性要求被替换为三个较弱的条件的削弱。经典命题连接词在非单调环境下具有自然的引入-消去规则。即使在非单调的设置,人们获得经典的命题逻辑,从而表明单调性是不需要证明经典的命题连接词。

英文摘要:

Tarski gave a general semantics for deductive reasoning: a formula a may be deduced from a set A of formulas iff a holds in all models in which each of the elements of A holds. A more liberal semantics has been considered: a formula a may be deduced from a set A of formulas iff a holds in all of the "preferred" models in which all the elements of A hold. Shoham proposed that the notion of "preferred" models be defined by a partial ordering on the models of the underlying language. A more general semantics is described in this paper, based on a set of natural properties of choice functions. This semantics is here shown to be equivalent to a semantics based on comparing the relative "importance" of sets of models, by what amounts to a qualitative probability measure. The consequence operations defined by the equivalent semantics are then characterized by a weakening of Tarski's properties in which the monotonicity requirement is replaced by three weaker conditions. Classical propositional connectives are characterized by natural introduction-elimination rules in a nonmonotonic setting. Even in the nonmonotonic setting, one obtains classical propositional logic, thus showing that monotonicity is not required to justify classical propositional connectives.

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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