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arXiv 2602.04073math.LO
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量词条件逻辑中的不完整性

Incompleteness in Quantified Conditional Logic

Alexander W. Kocurek, James Walsh, Yale Weiss

AI总结:

该研究指出,Stalnaker和Thomason的条件逻辑在以命题为输入的选择函数语义下是不完整的,且这一结论在多种语义设定下保持不变。

摘要:

Stalnaker和Thomason曾证明,带有一阶量词的条件逻辑C2在选择函数语义下是完备的。然而,这一完备性结果中所用的选择函数以公式而非命题(即世界集)为输入。然而Stalnaker多次强调,将选择函数视为对命题的函数具有哲学重要性,且其理论的许多应用都需要这一点。这些选择函数是否能被扩展到以命题为输入的选择函数语义下?我们证明答案是否定的:其逻辑在该语义下是框架不完整的。此外,这一结果在许多关于语义的选择点上具有不变性,例如变量域与常量域、是否包含身份或存在谓词等。最后,我们讨论了我们的结果所引发的一些重要的、困难的关于条件语义的哲学和逻辑研究问题。

英文摘要:

Stalnaker and Thomason famously proved that the conditional logic \textsf{C2} with first-order quantifiers is complete with respect to a selection function semantics. However, the selection functions used in this completeness result take formulas, rather than propositions (i.e., sets of worlds), as arguments. Yet Stalnaker has repeatedly emphasized the philosophical importance of viewing selection functions as functions on propositions, and many of the applications of his theory require this. Can their completeness result be extended to a selection function semantics in which the functions take propositions as arguments? We prove the answer is negative: Their logic is frame incomplete. Moreover, this result is invariant with respect to many choice points regarding the semantics, such as variable vs.~constant domains or whether to include an identity or existence predicate. We conclude by discussing some of the important and difficult questions for the philosophical and logical study of conditionals that our results raise.

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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