{"id":1870,"date":"2020-02-15T13:37:41","date_gmt":"2020-02-15T05:37:41","guid":{"rendered":"http:\/\/tsinghualogic.net\/JRC\/?page_id=1870"},"modified":"2026-11-10T09:34:50","modified_gmt":"2026-11-10T01:34:50","slug":"thulogicsalon","status":"publish","type":"page","link":"https:\/\/tsinghualogic.net\/JRC\/event-series\/thulogicsalon\/","title":{"rendered":"Tsinghua Logic Salon"},"content":{"rendered":"\t\t
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Initiated by the center’s students and researchers in 2019, the Tsinghua Logic Salon has quickly grown into a lively platform for try-outs and exchanges of new ideas. Researchers in various fields of logic are invited to present their latest research, as well as the challenges that they see. Every participant is encouraged to engage in discussions and exchange of perspectives. Each session lasts for 1.5 hours in total, with 30 minutes of discussion included.<\/p>

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Organizing Committee:<\/p>

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Junhua Yu, Chenwei Shi, Wei Wang, Han Xiao, Haoxuan Luo. (From June 2025 to Now)<\/p>

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Junhua Yu, Chenwei Shi, Wei Wang, Jialiang Yan, Penghao Du. (From September 2023 to June 2025)<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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\u25a0 Current Events<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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\n\t\t\t\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t2026 Nov 13 16:00-17:30 \u90dd\u5146\u5bbd (Fudan University) From Plato's Diairesis to Shelah's Dividing Line\u2014The long journey of exploring objective concepts<\/a>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t
We are focusing on Plato’s method of diairesis. This is a method for discovering definitions of concepts that he developed in a series of dialogues, including Phaedrus, Sophist, Statesman, and Philebus. Interestingly, Gregory Cherlin points out that Saharon Shelah’s strategy for dividing lines in contemporary model theory is a mathematical version of Plato’s “cutting through the middle.” John T. Baldwin<\/span> puts this more specifically: a dividing line is a property that must be both a “virtuous property” and its negation. In this talk, we will focus on more fundamental philosophical questions: Why do dividing lines exist? How can a philosopher or mathematician be sure that a dividing line has been discovered? The requirements for candidate dividing lines proposed by Shelah and the strategy of using the “test problem” parallel various actual methods of dividing in Plato’s dialogues. In essence, these requirements and strategies are actually intended to ensure that Plato’s requirement in the Sophist is to divide according to Form, that is, objective concepts as we understand them.<\/section>\n

About the speaker:\u00a0<\/strong>
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\n\t\t\t\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t2026 Nov 12 16:00-17:30 Paula Quinon (Warsaw University of Technology) What can we learn about natural numbers from cognitive modelling in conceptual spaces?<\/a>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t
The talk begins with a brief introduction to G\u00e4rdenfors\u2019s framework of conceptual spaces, in which concepts are modelled as regions in spaces built from quality dimensions. I then show how I use this framework to model the concept of natural number as a combination of several such spaces. I take the concept of natural number to be componential, distributed across at least four domains: the Approximate Number System (ANS), subitising, progression-regularity, and the symbolic system of numerals. Next, I focus on how the conceptual space of the ANS contributes to the conceptual space of the mature and professional concept of natural number. I use the model of the ANS to discuss concept learning. In particular, I explore the back-and-forth interactions between cognitive representations and cultural theoretical constructions (systems of notation, arithmetics, theories of computation) to understand how humans link the representations issuing from the ANS and other core cognition systems to the exact number words and numerals of their culture. Research funded with a Polish National Research Center grant OPUS21.<\/section>\n

About the speaker:\u00a0<\/strong>
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\n\t\t\t\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t2026 Nov 03 16:00-17:30 Valentin Shehtman (Moscow Institute of Physics and Technology, National Research University Higher School of Economics, Lomonosov Moscow State University) Simplicial models in modal predicate logic<\/a>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t
The talk is about simplicial semantics of modal predicate logic introduced in the 1990s by Dmitry Skvortsov. Although this semantics is not widely known, it is quite useful. Many logics that are incomplete in the standard Kripke semantics become complete in simplicial semantics, and an analogue of Sahlqvist theorem holds here. Another recent application is in the study of 1-variable fragments and expanding products of modal logics. In the talk we will state the corresponding results and briefly explain the methods of proofs.<\/section>\n

About the speaker: <\/strong>Valentin Shehtman works as a principal scientist at the Higher School of Modern Mathematics, Moscow Institute of Physics and Technology. He is also a Professor at Higher School of Economics and Moscow State University teaching different courses in mathematical logic. V. Shehtman is one of the leading specialists in nonclassical logic. He is an author of a research monograph \u201cQuantifcation in nonclassical logic\u201d (with D.Gabbay, D. Skvortsov) and about 50 papers. He solved several important and difficult problems in the field. His research is basically in modal logic and related areas, such as intuitionistic logic, algebraic logic, categorial logic; with the emphasis in model-theoretic and combinatorial methods.
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\n\t\t\t\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t<\/i><\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t2026 Oct 29 16:00-17:30 Tianming Yang (Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences) From Pac-Man to Language: Uncovering the Structure of Thought<\/a>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t
What is the relationship between thought and language? Both unfold as structured, sequential processes. In this talk, I will address this question through a study using the classic arcade game Pac-Man. We analyzed how humans and macaques played the game using a hierarchical model\u2014the Language of Problem Solving\u2014that represents gameplay as abstract strategies organized into structured, hierarchical sequences. Our analyses reveal that both species exhibit a \u201cgrammar\u201d of problem solving, but at markedly different levels of complexity: macaques rely primarily on simple grammatical structures, whereas expert humans construct complex strategic \u201csentences\u201d to navigate dynamic environments. Using fMRI, we linked this capacity in humans to a right-lateralized brain network that closely mirrors the left hemisphere\u2019s language network. These findings suggest that thought and language rely on similar computational principles for organizing structured sequences. More broadly, they point to a prefrontal\u2013parietal\u2013temporal circuit for structured sequence computation, of which language may be a specialized function.<\/section>\n

About the speaker: <\/strong>Tianming Yang, PhD, is Senior Investigator and Head of the Laboratory of Neural Mechanisms of Decision Making and Cognition at the Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences. His laboratory investigates how neural circuits in the primate brain support complex decision making and higher cognition, combining behavioral paradigms in macaque monkeys and humans with electrophysiology, computational modeling, and artificial neural networks. Dr. Yang received his PhD in Neuroscience from Baylor College of Medicine in 2003 and completed postdoctoral training at the University of Washington \u00a0(2003-2008). He then served as a staff scientist at the U.S. National Institute of Mental Health (2008-2013), before establishing his own laboratory at the Institute of Neuroscience in 2013. Dr. Yang\u2019s research has elucidated the neural mechanisms underlying probabilistic reasoning and decision-making within extended prefrontal and parietal networks. His work also explores how these computational principles can be modeled and applied to the development of artificial intelligence.
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Concurrent game models are a standard semantic framework for logics of strategic reasoning. Many influential logics in this area are interpreted over concurrent game models, including Alternating-time Temporal Logic (ATL), introduced by Alur et al. (2002), which is a key framework for reasoning about strategic and coalitional ability. Roughly speaking, a concurrent game\u00a0model<\/span>\u00a0consists of states and agents (forming coalitions), where, at each state, every coalition has available joint actions, and each such action induces a set of possible outcome states.<\/p>\n

Li and Ju (2025, 2026) argued that standard concurrent game models rely on three assumptions that can be too strong in practice. The first is seriality: coalitions always have available joint actions. The second is the independence of agents: merging two available joint actions of two disjoint coalitions always yields an available joint action of their union. The third is determinism: joint actions of the grand coalition always have a unique outcome.\u00a0<\/p>\n

There are eight classes of generalized concurrent game models, obtained by selectively imposing seriality, independence of agents, and determinism. In this talk,\u00a0I<\/span>\u00a0will present eight generalized alternating-time temporal logics, each based on one of these eight classes of models.<\/p>\n

We provide four semantics for these logics, based respectively on positional strategies, historical strategies, positional co-strategies, and historical co-strategies. We give fixed-point characterizations of the \u201cglobally\u201d and \u201cuntil\u201d operators and show that all four semantics are equivalent.\u00a0W<\/span>e also provide axiomatic systems for the eight logics and prove their soundness and completeness.<\/p>\n

If time permits, I will also discuss some potential applications of generalized alternating-time temporal logics.<\/p>\n

This talk is based on the following joint work with Yinfeng Li (University of Toulouse), Thomas \u00c5gotnes (University of Bergen and Shanxi University), and Emiliano Lorini (University of Toulouse):<\/p>\n