【作者】 萧瑶；

【导师】 何向东；

【作者基本信息】 西南大学 ， 逻辑学， 2008， 硕士

【摘要】 经典的信念逻辑系统S_KD45只能表达主体某个静止状态的信念及推理,事实上,在收到新信息后,主体的信念将发生变化。动态认知逻辑是动态逻辑和认知逻辑相结合的结果,它为信息变化提供了一种形式化的处理方法。本文旨在建立一个能处理信念变化的信念修正逻辑系统S_DBR。第一部分:首先介绍经典的信念逻辑系统S_KD45,该系统能较好地刻画相信算子的性质:无矛盾性、正内省性、负内省性,同时指出它的不足——不能描述动作所产生的变化,也不能刻画多主体间的相互作用。接着介绍传统的信念修正理论——AGM理论,它虽然能反映主体信念变化的过程,但并不是一个形式化的系统。第二部分:为了将信念排序,首先介绍顺序条件函数,它可以处理当主体收到带一定牢固度的命题后信念是如何变化的。在此基础上,引入静态的信念逻辑系统S_SBR,给出语言、语义以及证明系统,最后给出完备性的证明。第三部分:在静态的信念逻辑系统S_SBR基础上,将行动模型在认知逻辑中的执行作为动态模态算子引入逻辑语言中,建立动态的信念修正逻辑系统S_DBR。由于S_DBR可以归约到S_SBR,所以可以证明S_DBR也是完备的。第四部分:对S_DBR做出评价,指出不足之处,并指明在未来需要进一步研究的问题。更多还原

【Abstract】 The classical system of doxastic logic------S_KD45, can model agent’s belief and reasoningonly in some static states. In fact, after receiving a new piece of information to the belief set, the epistemic agent will change old belief set. Dynamic epistemic logic（DEL）, which merges dynamic logic and epistemic logic, provides formal means of analysis of information change.In this thesis, a logic system will be proposed------dynamic logic of belief revision（DBR）,which can model belief change .Part one: As a classical system------S_KD45. it is successful to express strongly the properties of belief: weaker knowledge; positive introspection; negative positive introspection. At the same time, it’s false to treat the change and interaction of multi-agent. Sequentially, although belief revision theory conceived by C.Alchourron, P.Gardenfors and D.Mackinson（AGM） treat the change successfully, it is not yet a formal system.Part two: An ordinal conditional function（OCF） expresses a ranking of propositions, and it represents agent’s revised belief after receiving a piece of information with firmness a. On the base of OCF, this paper introduces a static logic of belief revision （SBR）, including syntax, semantics and proof system. Finally, the logic system is proved complete.Part three: After extending the SBR, by introducing the execution of the action model in epistemic model as a dynamic operator into the logical language, this paper sets up a dynamic logic of belief revision （DBR）. It is can be proved that the DBR also is reduced to the SBR, so DBR system is complete too.Part four: I comment on the DBR, and give some problems for further research in the future.更多还原