学术资讯｜第28届德尔塔逻辑学工作坊

德尔塔逻辑学工作坊旨在汇聚来自数学、哲学和计算机科学领域的逻辑学研究者，促进不同学科之间的交流与合作。第28届德尔塔逻辑学工作坊（Delta 28 Logic Workshop）将在中山大学珠海校区举行。

地点：

中山大学哲学系（珠海）

海琴6号A542

时间：

2026年11月7日周六

报告人：

车晓舟（复旦大学）

陈昊睿（华南师范大学）

王云崧（北京大学）

姚博凯（北京大学）

张奉驹（中山大学）

章腾（浙江科技大学）

会议日程：

上午场（主持人：叶谨赫，香港大学）

09:00–09:50 车晓舟:

On weakly generic types in real formal series fields

摘要: Weakly generic types are a fundamental notion for definable groups in NIP structures, capturing canonical translation-invariant generic behavior. In this talk, we study weakly generic types of 𝔾ₐⁿ and 𝔾ₘⁿ in a monster model 𝕄 of Th(ℝ((t))) or Th(ℝ((t^ℚ))) with value group Γ_𝕄. For 𝔾ₘⁿ, a type is weakly generic if and only if its valuation pushforward is weakly generic in Γ_𝕄ⁿ, and all such types are ∅-definable. For 𝔾ₐⁿ, we give a valuation-theoretic characterization in terms of polynomials and their partial derivatives. Most notably, in contrast to the multiplicative case, we prove that there exist undefinable weakly generic types in 𝔾ₐⁿ. We close with two open questions on the fine structure and classification of weakly generic types in the additive setting. This is joint work with Ningyuan Yao.

09:50–10:40 陈昊睿:

An improvement on the lifting of posets

摘要: In this talk, we present an improvement on the lifting of partial order structures studied in previous work. This improvement provides a new method for constructing structures, allowing certain functions in the original structure as well as morphisms between structures to be lifted simultaneously. In particular, we apply this method to distributive lattices, obtaining a fundamental theorem for comparing classes of weak filters definable by quantifier-free positive formulas, which reduces the comparison of class-level inclusion relations to comparisons between finite structures. In addition, we attempt to demonstrate applications of this lifting method in other branches of mathematics.

10:40–11:10 茶歇及集体合影

11:10–12:00 王云崧:

Problem semantics for intuitionistic logic

摘要: The Brouwer–Heyting–Kolmogorov (BHK) interpretation understands formulas as problems and proofs as their solutions, offering a direct intuition for formulas and logical principles. Medvedev's problem semantics offers a concrete mathematical framework for this interpretation. However, the logic it yields, known as Medvedev logic, is a proper extension of intuitionistic propositional logic (IPC). The decidability of Medvedev logic remained a difficult open problem for decades. In September 2026, two works, both using generative AI, established its undecidability. Against this background, we revisit Medvedev's original aim of capturing intuitionistic logic itself through a precise semantics of problems and solutions. At the propositional level, we obtain two sound and complete problem semantics for IPC, inspired respectively by Friedman and Läuchli, thereby fulfilling Medvedev's original aim. Läuchli also explored a direct first-order extension, but it did not yield intuitionistic first-order logic (IQC). We identify the resulting logic and develop a more natural extension that captures IQC, proving soundness and completeness for both. In both the propositional and first-order settings, we establish a connection with constructive type theory, a central advantage of problem semantics. Building on these results, we plan to study intuitionistic mathematical theories and their constructive content through problem semantics.

12:00–14:30 午餐

下午场（主持人：吴刘臻，中国科学院数学与系统科学研究院）

14:30–15:20 姚博凯: 

The iterative conception reconsidered

摘要: According to the iterative conception of set, sets are formed in stages. This familiar picture is often taken to justify many standard axioms of set theory. But what exactly does the iterative conception say? I investigate the conception in its most general form, isolating its minimal commitments.I argue that the basic iterative conception is not robust: its natural formalizations are not equivalent, and their models can have very different structures. I then consider further principles of stage-unboundedness and reflection. These principles restore robustness, but in doing so give rise to distinct conceptions of set.

15:20–16:10 张奉驹: 

Identity crisis on tightly C⁽²⁾ compact cardinal

摘要: Bagaria and Goldberg asked if κ being tightly C⁽ⁿ⁾-compact implies κ∈C⁽ⁿ⁺¹⁾ for natural numbers n≥1? Usuba gave a negative answer for n＝1. In this talk we give a negative answer for n＝2.

16:10–16:30 茶歇

16:30–17:20 章腾: 

Super thick sets and their applications

摘要: There are many combinatorial notions in arithmetic Ramsey theory, which usually contain rich combinatorial and algebraic structures. In this talk, we introduce a notion called super thick sets, we will show that it has some good properties, and we will provide several applications.

17:20–20:00 晚餐

组织者：

申国桢（中山大学）

喻良（南京大学）

主办方：

中山大学哲学系（珠海）

来源｜哲珠新媒体

编辑｜赵一恬

初审｜陈怡平

审核｜卢　毅

审核发布｜陈建洪