第三十四次活动

形式：学术报告
时间：2014年12月19日(星期五） 下午2:30-5:00
地点: 清华大学新斋324会议室
主办: 北京市逻辑学会青年论坛; 清华大学-阿姆斯特丹大学逻辑学联合研究中心
报告人: Dan Robins (香港大学 教授）
题目: Later Mohist Nominalism
摘要: The idea that Later Mohist accounts of language are nominalists has been prominent in anglophone scholarship, starting with A.C. Graham and continuing especially with Chad Hansen. This paper takes up and mostly defends that idea, though stressing that the Later Mohists did not share the concerns that motivated nominalism in the west. Besides language, I focus on metaphysical issues, particularly the nature of kinds and of properties. I argue that Later Mohist metaphysics posits only particular entities and the similarities and differences among them; properties such as hardness and whiteness are themselves particular entities that exist in their instances. Unfortunately the Later Mohists give no account of similarity that would enable them to avoid standard objections to western forms of nominalism.

第三十三次活动

形式：学术报告
时间：2014年7月04日(星期五） 上午9:30-11:30
地点: 北京师范大学教二-203 教室
主办: 北京市逻辑学会青年论坛; 北京师范大学
报告人: Johan van Benthem (阿姆斯特丹大学和斯坦福大学教授；清华大学长江讲座教授）
题目: Natural Language and Logic of Agency
摘要: We reflect on analogies between two often disjoint streams of research: the logical semantics and pragmatics of natural language and dynamic logics of information-driven agency. The two areas show significant overlap in themes and tools, and yet, the focus seems subtly different in each, defying a simple comparison. We discuss some unusual questions that emerge when the two are put side by side, in a light manner.

第三十二次活动

形式：“知识、理性和决策”小型研讨会
时间：2014年3月1日(星期六）下午2:00-5:30
地点: 清华大学新斋346会议室
主办: 北京市逻辑学会青年论坛; 清华大学-阿姆斯特丹大学逻辑学联合研究中心
报告人: Mamoru Kaneko（日本早稻田大学 教授）； 刘水歌（日本早稻田大学 研究生）；石辰威（清华大学 研究生）

第三十一次活动

形式：学术沙龙
时间：2013年10月6日(星期日）下午2:30-5:30
地点: 清华大学新斋346会议室
主办: 北京市逻辑学会青年论坛; 清华大学哲学系
主讲人: Alexandru Baltag（阿姆斯特丹大学）
主题: Dynamic Epistemic Logic
主要参与学者: 郭佳宏；刘奋荣；琚凤魁； Sonja Smets; Zoe Christoff

第三十次活动

形式：学术报告
时间：2013年5月11日(星期六）上午9:30-11:30
地点: 清华大学新斋346会议室
主办: 北京市逻辑学会青年论坛; 清华大学哲学系
报告人: 王轶（挪威卑尔根大学博士生）
题目: preference logic of focus change
摘要: In recent work Xiong and Seligman introduced a logic for reasoning about preferences and decision making in a setting where the agent focuses on a subset of all alternatives (such as possible seminars to attend), and where new alternatives can come into focus as the result of questions of the type ``have you heard of the Beijing logic forum for young scholars'' being asked. A logical is proposed, axiomatized and the axiomatization proved complete, but there is a gap we find between the motivating example and the formal semantics. We present a modification of Xiong and Seligman's logic, basically consisting of representing the alternatives under consideration semantically rather than syntactically. We argue that this semantics captures the intended meaning better. We also present a sound and complete axiomatization of the resulting logic.

第二十九次活动

形式：学术报告
时间：2013年4月20日(星期日）上午9:00-11:30
地点: 清华大学新斋335会议室
主办: 北京市逻辑学会青年论坛; 清华大学哲学系
报告人: Ram Ramanujam
题目: Exploring compositional structure in strategies
摘要: If we know that strategy $x$ "works" in game $g$ and strategy $x'$ in game $g'$, then how do we build a strategy in game $g op g'$ based on $x$ and $y$ ? When the operator $op$ is simple subgame composition (so that we now have a game with a choice of exploring both subgames), this question has an elegant answer for finite two-player zero-sum games of perfect information. We discuss classical results of this kind to suggest that exploring algebraic structure (games quotiented under suitable equivalences) is worthwhile, and point out that familiar and reasonable operators already pose interesting challenges, as soon as we relax any of the conditions listed above (finite, two-player, zero-sum, perfect information).
报告人简介: R. Ramanujam is a researcher in theoretical computer science from the Institute of Mathematical Sciences, Chennai, where he is currently professor. His research interests are in mathematical and philosophical logic with applications to theory of distributed systems, security theory and game theory, and the connections between logic and automata theory. He is an editor of ACM transactions on computational logic and was a Lorentz Fellow in the Netherlands in 2010.
He is involved in science and mathematics popularization and education, especially in rural areas in India and is editor of Thulir, a monthly children's science magazine.

第二十八次活动

形式：学术报告
时间：2013年3月24日(星期日）上午9:30-11:30
地点: 清华大学新斋346会议室
主办: 北京市逻辑学会青年论坛; 清华大学哲学系
报告人: Thomas Agotnes（挪威卑尔根大学）
题目: Reasoning about coalitional ability in games: Coalition Logic vs. PDL
摘要:The use of modal logics for reasoning about games has been of considerable interest in recent years. One popular framework is Pauly's coalition logic (CL), developed to reason about coalitional abilities of the form "coalition C have the ability to make formula phi true no matter what the other agents do". CL can be seen as the next-time fragment of Alternating-time temporal logic (ATL). Another framework is propositional dynamic logic (PDL), which, although developed to reason about the execution of computer programs, can also be used to reason about games. In this talk, I will discuss some aspects of the relationship between the two, in particular how PDL can be used to reason about coalitional ability. An advantage of PDL over CL is that it is a standard, normal, modal logic. There is a restriction to this approach: it can only be used to reason about game structures that are injective. I will discuss consequences on this restriction, in particular for the so-called playability properties of effectivity functions, and present a variant of Pauly's representation theorem for effectivity functions of injective games. The talk is based on joint work with Natasha Alechina.

第二十七次活动

形式：学术报告
时间：2012年10月12日(星期五）下午 2：00-4：00
地点: 北京师范大学主楼A809
主办: 北京市逻辑学会青年论坛; 北京师范大学逻辑与认知科学研究所
报告人: Johan van Benthem（阿姆斯特丹大学和斯坦福大学教授）
题目: Logic, Information and Agency
摘要 : Already the ancient logicians saw logic as related with at least three major sources of information: not just inference, but also perception and communication. In this talk, I will describe some current dynamic logics exemplifying all three sources, dealing with observation, questions, and acts of inference. Some have a relatively well-developed theory, some are just starting, and I will point out some open problems in each. I will also discuss some challenges in combining the three information sources, and in connecting the logical perspective to other views of processes of inquiry, from learning theory to cognitive science.

Ref. Johan van Benthem, 2011, "Logical Dynamics of Information and Interaction", Cambridge University Press, Cambridge.

报告人简介：Johan van Benthem，是阿姆斯特丹大学的大学教授，斯坦福大学的Henry Waldgrave Stuart哲学教授， 中国教育部海外名师，清华大学伟伦教授，中山大学客座教授。他也是欧洲科学院院士和荷兰皇家文理科学院院士， 国际哲学院士。他是阿姆斯特丹大学逻辑、语言和计算研究所的创立者和首任主任，也是欧洲语言、 逻辑和信息协会的首任主席和首位荣誉会员。他主要研究模态逻辑、时态逻辑、自然语言的逻辑语义学和语法， 以及计算、交流和博弈的动态逻辑。目前的研究主要集中于解决逻辑、计算机科学和博弈论的结合基础上的智能互动问题。 1996年至2001年间，他获得荷兰最高科学奖斯宾诺莎奖的资助。

第二十六次活动

形式：学术报告
时间：2012年8月4日(星期六） 3:00 -- 5:00 pm
地点：北京师范大学主楼A802

报告人报告人: Peter Vranas（University of Wisconsin-Madison）
题目:New Foundations for Imperative Logic 3: A General Definition of Argument Validity
摘要: Besides pure declarative arguments, whose premises and conclusions are declaratives (“you sinned shamelessly; so you sinned”), and pure imperative arguments, whose premises and conclusions are imperatives (“repent quickly; so repent”), there are mixed-premise arguments, whose premises include both imperatives and declaratives (“if you sinned, repent; you sinned; so repent”), and cross-species arguments, whose premises are declaratives and whose conclusions are imperatives (“you must repent; so repent”) or vice versa (“repent; so you can repent”). I propose a general definition of argument validity: an argument is valid exactly if, necessarily, every fact that sustains its premises also sustains its conclusion, where a fact sustains an imperative exactly if it favors the satisfaction over the violation proposition of the imperative, and a fact sustains a declarative exactly if, necessarily, the declarative is true if the fact exists. I argue that this definition yields as special cases the standard definition of validity for pure declarative arguments and my previously defended definition of validity for pure imperative arguments, and that it yields intuitively acceptable results for mixed-premise and cross-species arguments.

第二十五次活动

形式：学术报告
时间：2012年8月3日(星期五） 10:00 -- 12:00
地点：清华大学新斋353

报告人: Chris Fraser（University of Hong Kong）
题目: Truth in Mohist Dialectics
摘要: The Mozi famously proposes three “standards” (biao 表) or “models” (fa 法) as criteria for evaluating teachings, claims, or policies. A longstanding controversy in the interpretation of Mohist thought concerns exactly what the three standards are criteria of. Are they intended to evaluate whether a teaching is true, morally right, pragmatically useful, or something else? A seemingly natural interpretation, motivated partly by Western philosophical assumptions, is that the models are criteria for judging the truth of an assertion or theory. Watson, for instance, interprets them as three tests of the “validity” of a “theory.” Schwartz and Wong both take them to be three tests for “verifying a proposition.” Graham calls them three tests of “assertion” and contends that they concern issues that are “purely factual.” In a more recent discussion, Van Norden suggests that they are “indicators of truth.” Against these interpretations, Hansen has contended that the best explanation of the first and third models is that the Mohists are concerned not with truth, but with “appropriate word or language usage” or pragmatic “assertibility.” He suggests that the Mohists are not treating the semantic issue of how to determine whether a sentence is true, but the pragmatic one of how to determine whether the use of words is appropriate.

The general approach of evaluating statements, actions, and policies by distinguishing whether they are relevantly similar to a standard figures prominently both in the core books of the Mozi (books 8–37) and in the Mohist dialectical texts—the six books that form the so-called “later Mohist” texts or Mohist “Dialectics.” Both use the same terminology for such criteria, referring to them as fa (model, standard). Unlike the core books, however, passages in the dialectical texts explicitly treat semantic issues, such as the grounds by which to distinguish whether things fall under the same general term and the status of utterances disputants might make in a debate over which of two terms fits an object. If the three standards are not criteria of truth, are these later Mohist texts also evaluating utterances in terms of some pragmatic status, rather than truth? Does a concept akin to truth have any role in Mohist dialectics, whether in the core books or the dialectical texts? Hansen argues boldly that “Chinese philosophy has no concept of truth” and that later Mohist thought instead applies purely pragmatic, not semantic, terms of evaluation. Utterances are evaluated as to whether they are “admissible” or “assertible” by practical standards, not by whether they are correct in a specifically semantic sense. He offers three main arguments for this interpretation. The first is that early Chinese theories of language had a pragmatic, not semantic, orientation, and thus there was no role for a concept of truth. The second is that early Chinese thinkers did not theorize about the status of sentences, the units of language that admit of evaluation as true or false. The third is that Mohist dialecticians evaluated the status of utterances not in terms of a concept corresponding to truth, but in terms of whether they were ke 可 (“permissible”), a concept with a pragmatic connotation.

This essay will review the case for the claims that the Mohists’ three standards are something other than standards of truth and that even later Mohist dialectics employs no term of semantic evaluation corresponding to “true.” I will argue that Hansen is correct that the three standards are not criteria of truth, specifically, but of a more general notion of the correct dao 道 (way). However, they do not preclude a concern with truth, and their scope probably covers questions of truth. Later Mohist dialectics likewise does not focus specifically on truth or employ a concept that aligns exactly with “true.” Nevertheless, I will argue, the texts do employ terms that play the same expressive role as “…is true.” Thus, contra Hansen’s thesis, these texts can justifiably be said to have a concept of semantic truth.

第二十四次活动

形式：学术报告
时间：2012年3月18日(星期日） 10:00 -- 12:00
地点：清华大学新斋335

报告人:Alessandra Palmigiano（ILLC, University of Amsterdam）
题目: Epistemic updates on algebras
摘要: We introduce a methodology, based on duality theory, which makes it possible to study epistemic updates from an algebraic perspective. We focus on the case study of public announcements, and hence on Public Announcement Logic (PAL) without the common knowledge operator. As is well known, the epistemic action of publicly announcing a given proposition is semantically represented as a transformation of the model encoding the current epistemic setup of the given agents; the given model shifts to its submodel relativized to the announced proposition. We give the dual characterization of the corresponding submodel-injection map, as a certain pseudo-quotient map between the complex algebras respectively associated with the given model and with its relativized submodel. As is well known, these complex algebras are complete atomic BAOs (Boolean algebras with operators). The dual characterization we provide naturally generalizes to much wider classes of algebras, which include, but are not limited to, arbitrary BAOs and arbitrary modal expansions of Heyting algebras (HAOs). In this way, we access the benefits and the wider scope of applications given by a point-free, intuitionistic theory of epistemic updates. As an application of this dual characterization, we axiomatize the intuitionistic analogue of PAL, which we refer to as IPAL; we provide relational semantics for IPAL, we prove soundness and completeness of IPAL w.r.t. both algebraic and relational models, and we show that the well-known Muddy Children Puzzle can be encoded in IPAL.
(Based on joint work with M. Ma and M. Sadrzadeh)

第二十三次活动

形式：学术报告
时间：2011年11月5日(星期六） 10:00 -- 12:00
地点：清华大学新斋346

报告人: 熊明辉 教授（中山大学）
题目: Logics for Legal Argumentation
摘要: This topic about logics for legal argument stems from Protagoras, who is the first sophist in Ancient Greece and presented the paradox of the court. In Aristotle's logical works Organon, what his treatise On Sophistical Refutations discussed is how to refute sophist's argumentation and to discover their fallacies. In 1588 Abraham Fraunce published the Lawier Logike exemplifying the praecepts Logike by the practise of the common Lawe. In his poem, he said, "I see no reason, why that Law and Logike should not bee. The nearest and the dearest freends, and therefore best agree.…… I sought for Logike in our Law, and found it as I thought."

As a symbol of legal realism, Jr. Oliver Wendell Holmes said in 1881, "The life of the law has not been logic; it has been experience". Therefore, most scholars have wrongly thought that Holmes tried to reject the important role of logic in the law up to now. However, it is not what Holmes really wanted to say. On the contrary, in 1897 Holmes stressed that the training of lawyers was a training in logic and the language of judicial decision was mainly the language of logic. Interestingly three book reviews were published on the Columbia Law Review's 31st issue of 1931after Jerome Frank's book Law and the Modern Mind was printed. Karl Llewellyn thought Frank's idea was keen, cogent and well-integrated; therefore, logic lost its function in the law domain, while Mortimer J. Alder claimed that legal certainty need to be maintained by formal logic and judicial decision was the outcome of deductive logic. But Walter Wheeler Cook thought Frank hadn't actually denied the role of formal logic in the law but was trying to show how lawyers had misconceived and misused formal logic.

The systematic study of logics for legal argument started from the middle period in last century, i.e., after Ulrich Klug published his book Juristische Logik in 1951 and Lee Loevinger issued his paper 'An Introduction to Legal Logic'. Since then, logics for legal argumentation have been going forward along two paths - formal and informal. The former is based on formal logic while the latter's basis is informal logic or argumentation theory. Absolutely, both Klug and Loevinger regarded legal logic as an applied modern logic while as an applied traditional logic before their theories. In 1958 Cha?m Perelman et al and Stephen Toulmin published respectively Traité de l'argumentation, la Nouvelle Rhétorique and The Uses of Argument. It is they that opened up the path to study logics for legal argumentation from a perspective of non-formal logic. Although some scholars who are walking on the two roads seem to understand each other sometimes, we think it is possible to integrate the two lines. In this talk, we will show this kind of possibility.

第二十二次活动

形式：小型学术会议 Mini-Workshop on Modal Logic, Language and Logical Dynamics
时间：2011年6月12日(星期日） 13:00 -- 18:00
地点：清华大学新斋324

第二十一次活动

形式：学术报告
时间：2011年5月3日(星期二） 10:00 -- 12:00
地点：清华大学新斋238

演讲人：何莫邪 教授 (奥斯陆大学)
题目：逻辑分析和古汉语研究

何莫邪简介：世界著名汉学家，奥斯陆大学东欧与东方研究系教授，挪威科学院院士。 1980年代曾在剑桥协助李约瑟从事“中国科学与文明”的研究，负责中国传统语言与逻辑部分。 担任国内外知名大学客座教授。

第二十次活动

形式：学术报告
时间：2011年4月17日(星期日） 9:30 -- 13:00
地点：北京师范大学主楼B805

演讲人：王彦晶博士 (北京大学)
题目：隐协议
摘要: 本文试探讨当社会协议不是公共知识的情况下， 人们是如何根据观察和对协议的片面知识进行推理的。我们在认知模型上加入期待观察的信息， 研究了这种期待观察的信息是如何从不是公共知识的协议中得到的。 我们还给出了这些非公共协议间的一种等价关系，并设计了一种认知逻辑来处理主体基于非公共协议和观察的认知推理。
本文是与 Hans van Ditmarsch， Sujata Ghosh 及 Rineke Verbrugge的合作工作。

演讲人：马明辉 (清华大学博士研究生)
题目：Mathematics of Public Announcements
摘要: We study some mathematical aspects of public announcement logic (PAL) and its several variants. We first give a variant characterization theorem of van Benthem’s result that uses recursion axioms to characterize the submodel operation. Then we show some model-theoretic results on the respecting phenomena of the submodel operation with respect to some model constructions. The second approach to understand public announcements is an algebraic one. Based on a joint work with Alessandra Palmigiano (Amsterdam) and Mehrnoosh Sadrzadeh (Oxford), we give a dual characterization of the corresponding submodel-injection map, as a certain pseudo-quotient map between the complex algebras respectively associated with the given model and with its relativized submodel. We show the algebraic soundness and completeness result for PAL. We still generalize this algebraic approach to public announcement extension of epistemic intuitionistic modal logic. Finally, we give some observations on the public announcement extensions of first-order logic as well as epistemic predicate modal logic.

第十九次活动

形式：学术报告、讨论会
时间：2010年11月7日 上午9:00 -- 下午5:00
地点：人民大学人文楼601

演讲人：王彦晶博士 (北京大学)
题目：Reasoning about protocol change and knowledge
摘要:In social interactions, protocols govern our behaviour and assign meaning to actions. In this paper, we investigate the dynamics of protocols and their epistemic effects. We develop two logics, inspired by Propositional Dynamic Logic (PDL) and Public Announcement Logic (PAL), for reasoning about protocol change and knowledge updates. We show that these two logics can be translated back to the standard PDL and PAL respectively.

演讲人：琚凤魁 (北京大学博士研究生)
题目：Semantics of Sentences in Mixed Moods
摘要: Based on the framework of update semantics, this paper aims to present a dynamic semantics for English sentences in mixed moods of indicative and imperative. The main difficulty of defining such a semantics lies in that the connectives , and - behave differently in this sort of language phenomenon from our usual understanding of them: Conjunctions and disjunctions might contain conditionals in meaning; Imperatives have imperative forces even if they occur in disjunctions. To solve this difficulty, we define possibilities in information states as binary tuples, which consist of possible worlds and force states. Then we introduce stacks, which are divisions of information states. Meaning of sentences is defined as an update function on stacks. Not genuinely introducing new connectives, this treatment makes information states change in the way we expect. In the update framework, this semantics can produce a reasonable notion of validity.

演讲人：周北海教授 (北京大学)
题目：概念语义与弗雷格迷题消解
摘要:弗雷格因同一替换律讨论而提出了涵义与指称的理论，这个理论后来引出了弗雷格迷 题。弗雷格迷题的形成有多方原因，直接指称论对弗雷格理论批评是主要原因之一，以至于可 以说，这是产生于直接指称论哲学立场的迷题。尽管如此，弗雷格理论确有不足。最重要的是， 弗雷格理论只有关于涵义与指称的理论，即只有语言层面的理论，而缺少认知层面的理论。这 个不足使得在弗雷格理论基础上解决同一替换律问题难有令人满意的结果，让“迷题”多添了 几分“迷”的色彩。这里将给出一个新的方案：在弗雷格理论的基础上，增加有关概念的理论， 以概念和内涵、涵义等这些概念的形式刻画为中心，建立可以消解弗雷格迷题的形式语义学， 即概念语义。通过概念语义可以在不同层次上对弗雷格迷题的消解给出统一回答。

第十八次活动

形式：学术报告
时间：2010年9月7日(星期二） 上午10:00 -- 12:00
地点：社科院大楼957室(逻辑研究室）

演讲人：琚凤魁 (北京大学博士研究生)
题目：祈使句的语义和逻辑
摘要 We will present a series of dynamic semantics for imperatives in the framework of update semantics, and specify several alternative logics for imperatives. In these semantics the consistency problem and Ross’s paradox have straightforward solutions. All the work is carried out based on the correspondence between imperatives and force structures. According to different ways of dealing with compatibility between imperatives, we give a few choices of de?ning the notion of consistency for imperatives. Meaning of imperatives is an update function on force structures, which is also dependent on compatibility. Entailment for imperatives is reduced to some relation between force structures. We also give some choices of the notion of entailment, each of which is coincident with a certain kind of compatibility.

第十七次活动

第十六次活动

第十五次活动

第十四次活动

第十三次活动

第十二次活动

第十一次活动

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第九次活动

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第七次活动

第六次活动

摘要: 一个Frege系统是一个基于有限多规则和公理模式之上蕴涵完全的命题证明系统。 一个Frege系统F多项式模拟另外一个Frege系统H，是说有一个多项式时间算法把命题公式A的任意 一个F-证明翻译成A的H-证明。我们首先提出一个以广义Sheffer竖为初始联结词的命题逻辑系统， 其中括号将兼具联结词作用。运用这个系统可以构造一个组合重言式的序列， 把这些重言式加到任意一个Frege系统的时候，可以多项式模拟扩张的Frege系统。

摘要: The celebrated Sahlqvist correspondence theorem says that every Sahlqvist formula has a first-order correspondent computed automatically from it using Sahlqvist-van Benthem algorithm. It follows that every Sahlqvist formula is canonical for its first-order correspondent. This is called Sahlqvist completeness theorem. It is hard to extend the class of Sahlqvist formulas by weakening the definition of a Sahlqvist formula. But for the completeness theorem, there is a natural extension. The motivation of extending it comes from the logic KMT proposed by G. Hughes [1990] which is generated by a set of formulas of the form $<>/\_{i=1}^n(<>p_i --> []p_i)$. P. Balbiani, I. Shapirovsky and V. Shehtman [2006] took this road and introduced a class of modal logics which is complete with respect to a class of frames satisfying certain first-order condition which can be computed automatically. They added the diamond to a conjunction of the form $/\_{i=1}^n\phi(p_1^i,...p_m^i)$ where $\phi(p_1,...,p_m)$ is a locally elementary and locally d-persistent modal formula. Note that they only use the prefix $<>$. My results is to prove that all positive modalities work for the purpose. A hierarchy of modal formulas is also defined and some model-theoretic results follows.

第五次活动

摘要: 17和18世纪数学繁荣的速度令人惊奇，但是其不受约束地发展也令数学家和逻辑学家开始关注严格性、 概念的清晰性、概念的还原性、系统组织和解释等问题。特别是实数与复数分析中无穷小、 无穷和与无穷积的使用产生问题，后来为了系统的严格性，这些概念逐渐被极限的概念所替代。 然而复数的概念产生于一个"想象" 数 i = sqrt[-1]，数学家开始寻找复数理论的坚实基础。 这个坚实基础就是靠还原工作提供的。复数的概念可以还原为实数概念， 实数概念可以还原为有理数概念，有理数概念可以还原为自然数概念。 然而怎样将自然数还原为更为基础的概念，从而给数学以可以信赖的基础， 成为了康托、弗雷格、罗素以及策梅洛等人后来致力的方向。 本次讲座旨在从还原的角度看这些数学基础发展的脉络和相互关系。

摘要:本文的主要目标是构造分析性模态公理系统，这种系统的定理证明很简单。 称公理系统具有分析性，即推理规则的前提和结论的命题变元相同。 分析性公理系统始创于安德森等构造的经典逻辑系统，本文将这种方法推广到模态逻辑。
为了便于表述分析性公理系统的公理，本文给出模态表达式的一种新记法，即定义一个n元算子，它实际上混合了广义析舍和模态词，能节省联结词和括号，故称为广义谢弗竖。以新记法为基础，本文改进了现有的两种模态表列：破坏性表列和前缀表列。经改进的模态表列的推演性概念很有特点。由改进的模态表列和超矢列的方法，本文构造了两种分析性模态公理系统：基于破坏性表列的和分组的，它们都是在命题逻辑的分析性公理系统的基础上增加模态规则（而不是模态公理）得到的。分析性模态公理系统和模态表列存在一种对应关系，因此这种系统的完全性由表列完全性易证，并且一个表达式在系统中的证明可由该表达式的表列证明机械地得出。分析性公理系统的另一优点是系统的可判定性可直接证明。此外，我们由分析性公理系统得到了一种新的推演的定义。虽然这种系统没有分离规则，但其演绎关系仍有自返性，单调性，切割性和替换性，故这种新的演绎的定义是合理的。
最后，本文考察了基于这种新记法的萨奎斯特对应定理的形式。

第四次活动

第三次活动

题目: 谁之错? —— 陈慕泽vs周北海

形式：辩论
主持人：刘壮虎
时间：2008年12月6日（星期六）上午9:30 — 12:00
地点：中国人民大学 二教409

背景简介

2001年陈慕泽发表论文“全称概括规则和受限制的演绎定理 —— 国内数理逻辑教材中的一个问题”，认为关于可证、演绎定理和全称概括规则的表述 “国内一些有影响的数理逻辑教材或专著中存在的一个重要错误”。 2007年秋，周北海看到此文，认为陈慕泽文章本身有错。此后二人多有争论，终于约定公开辩论。

此次活动属教学问题讨论，形式与以往活动不同。辩论将由一人主持，全体与会者为评判人，共同评判是非。欢迎参加。

附件：全称概括规则和受限制的演绎定理 —— 国内数理逻辑教材中的一个问题

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第二次活动

形式：学术报告
时间：2008年10月28日(星期二） 3:30-5:00
地点：北京大学哲学系 会议室

摘要: 在多主体认知逻辑中，群体知识对于主体间的互动有重要作用。分布式知识就是群体知识中的一种。 分布式知识的直观含义（称为"联合知识"）与通常接受的语义解释（称为"群体隐含知识" ）并不是一致的。符合完全交流原则的群体隐含知识和联合知识是一致的。 形式化分析表明这两种知识只有在一些特殊的模型类中才是一样的。有穷可分辨模型、紧密饱和模型、饱和可分辨模型都符合完全交流原则。只有完全交流模型才真正完全地刻画了完全交流原则。 群体隐含知识和联合知识不一致的根本原因涉及到可能世界的本体论地位问题。

形式：学术报告
时间：2008年10月28日(星期二） 1:30-3:00
地点：北京大学哲学系 会议室

摘要: 本论文试图解决的中心问题是NExtK4中濒表格逻辑的判据问题．所谓"濒表格性的判据"总不外是这样一个语义论断： 逻辑L是濒表格的iff存在一如此这般的无穷框架F使得L＝LogF．这个存在命题丝毫不意味着不存在非如此这般的无穷框架使得L＝LogF． 可见，濒表格性判据本身预设了要在刻画同一个逻辑的--往往被称作"等价的"-许许多多框架中作取舍． 我们把这种取舍过程叫做"规范化"． 规范化的手段是各种框架变换，其根本目的不是只求刻画框架在几何性状上的优雅， 而是要追求刻画框架在结构性状上的稳定．为此我们引入点式归约的概念和点式归约下不变性概念． 这两个概念使得我们能够指出这个规范化过程在一个什么样的合理标准下结束。换句话说， 在点式归约下的不变性从一个最重要的侧面反映了濒表格性的本质．对点式归约进行的初步研究发现， 我们可以对不含无穷深点的传递框架上的点式归约做一个穷尽的分类．同时，对有穷传递框架来说， F是既约的iff F在点式归约下不变．其后，我们分别针对有穷深度的与无穷深度的濒表格逻辑制订判据． 在解决有穷深度濒表格逻辑的判据问题的时候，我们引进了"AltN-颠覆子"和"强的AltN-颠覆子"的概念， 从无穷框架入手，得到有穷深度濒表格逻辑的范形及其所满足的抽象性质，从而得到判据．值得指出的是， 我们用在点式归约下不变作为鉴别濒表格逻辑的刻画框架的范形的重要标准．在解决无穷深度濒表格逻辑的判据问题时， 我们则是从濒表格逻辑的有穷有根刻画框架类入手，从中抽取一条满足若干条件的有穷有根框架链， 最后通过链并的方式得到无穷深度濒表格逻辑的范形．同样地，在点式归约下不变是一个重要的判定标准． 在得到濒表格逻辑的这些判据之后，我们把得到的判据应用到NExtQ4并且证明和NExtK4类似，这个格也存在着濒表格逻辑的连续统． 另外我们也初步研究了NExtQ4中一些濒表格逻辑的公理化问题．最后，作为一个插论，我们把某些零散结果收入最后一章． 这些结果与传递逻辑中的一个新方向密切相关， 主要指向无穷深度的濒表格逻辑与框架逻辑、子框架逻辑、共尾子框架逻辑之间的关系．

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第一次活动

形式：学术报告
题目：基于涵义语义的范畴空间—— 兼谈逻辑与认知
演讲人：周北海 教授 （北京大学）

时间：2008年10月18日(星期六）上午9：30-12：00
地点：中国人民大学 求是楼0223

摘要: 每个概念集在可能世界上由内涵的包含于关系形成一个偏序结构，这就是一个范畴空间。范畴空间也是概念的定位系统和理解系统。范畴空间是传统概念理论在现代逻辑方法下的发展。概念理论已经淡出逻辑学领域，成为认知语义学的重要内容。这里有逻辑学本身的原因，也有概念自身特点方面的原因，主要原因是概念与认知有密切关系。范畴空间与认知语义学中 Gardenfors 的概念空间形成不同层次的互补关系，可以作为认知语义学的一部分。这表明逻辑学应该也可以深入到认知结构的研究中。Lakoff "形式逻辑没有办法刻画人类的概念和理性”的观点过于极端。认知语义学的核心观点是在语言和对象之间存在认知结构的中间层。对于这个中间层面 目的全面揭示，有待于认知语义学和逻辑学的共同研究。