This paper develops a deontic logic for defeasible permission and studies norm change in various updated semantics. When one grants that $\varphi $ or $\psi $ is permitted, normally, it goes together with the conjunction of a permission of $\varphi $ and that of $\psi $. In the monotonic reasoning on this permission, a permission of $\varphi $ leads to a permission of $\varphi $ and $\psi $; however, if a prohibition of $\psi $ is introduced, we get into trouble. We face a paradox of free choice permission. Many solutions have been proposed, but a systematic account of handling norm change is still needed. This paper first introduces the notion of normality to develop a sound and complete deontic logic for defeasible permission, which can be used to analyse several notions in natural language and in game theory. Further, following Lewis’ idea of norm change, a systematic way to capture various dynamics for updating permission and obligation is proposed.

中文翻译：

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可废止许可的逻辑及其动态

本文开发了一种可废止许可的道义逻辑，并研究了各种更新语义中的规范变化。当一个人授予 $\varphi $ 或 $\psi $ 被允许时，通常它与 $\varphi $ 的权限和 $\psi $ 的权限的连词一起出现。在这个权限的单调推理中，$\varphi $ 的权限导致$\varphi $ 和$\psi $ 的权限；但是，如果引入了 $\psi $ 的禁令，我们就会遇到麻烦。我们面临着自由选择许可的悖论。已经提出了许多解决方案，但仍然需要系统地说明处理规范变化。本文首先引入常态概念，为可废止许可建立健全完整的道义逻辑，可用于分析自然语言和博弈论中的若干概念。进一步，