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15
2025/07
Codes, groups and designs
Theadjacency code of a rank three group contains PBIBDs by construction. When weare lucky we obtain a BIBD also known as 2-design. This is the casefor instance of the one point stabilizer of PSL(2,41) in its action onthe binary QR(41). When we are even luckyer we obtain a 3-design inthe extended code. This is the case of the XQR(41) in length 42. Byconsidering known families of rank 3 groups we obtain in that way 111 2-designand nine 3-designs. The supporting codes are constructed by modularrepresentation theory. ( joint works with Bonnecaze and with Rodrigues). Anothergroup action method applies to isodual ternary codes the automorphism group ofwhich admits two orbits on triples (joint work with Shi and Liu.) Interestingexamples are provided by Generalized Quadratic Residue codes, a family ofabelian codes discussed by van Lint and MacWilliams. Since none of thediscussed designs can be explained by the Assmus-Mattson theorem ortransitivity arguments, all of this work is based on computer calculationsin Magma. Recently a theoretical explanation of the designs in the weight10 codewords of the XQR(41) was provided by Munemasa based on harmonic weightenumerators.
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15
2025/07
Banach Spaces with the Ball Covering Property
A Banach space is said to have the ball coveringproperty if its unit sphere can be covered by countably many open balls off theorigin. The ball covering property is a property that has close relationshipswith the topological properties and geometric properties of Banach spaces. Inthis talk, we will give a review of the historical literature and present somerecent advances on this topic. Open problems will be proposed, and approacheswill be discussed.
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14
2025/07
Projected Sobolev gradient flows and its application to compute ground state of ultracold dipolar fermi gas
We first provide an overview of gradient flow for minimization problem. Then we note that the ground state for the ultracold fermi gas with dipole-dipole interaction is a functional minimization problem based on density functional theory (DFT). We extend the recent work on Sobolev gradient flow for the Gross-Pitaevskii eigenvalue problem, and present continuous projected Sobolev gradient flows for computing the DFT-based ground state solution of ultracold dipolar fermi gas. We prove that the gradient flows have the properties of orthonormal preserving and energy diminishing, which is desirable for the computation of the ground state solution. Many numerical technique for partial differential equation can be used to discretize the time-dependant projected Sobolev gradient flows, which may be an advantage of the method. We propose an efficient and accurate numerical scheme – semi-implicit Euler method in time and Fourier spectral method in space for discretizing these projected Sobolev gradient flows and use them to find the ground states of the fermi gas numerically. Extensive numerical examples in three dimensions for ground states are reported to demonstrate the power of the numerical methods and to discuss the physics of dipolar fermi gas at very low temperature.
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09
2025/07
氦离子显微镜的原理与应用
氦离子显微镜的原理与应用。包括发展历史与工作原理、应用方向、总结展望。
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18
2025/07
人类世中的鸟类多样性保护
人类世中的鸟类多样性保护
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13
2025/07
Dietary isothiocyanates derived from glucosinolates in cruciferous vegetables and cancer management
Dietary isothiocyanates derived from glucosinolates in cruciferous vegetables and cancer management
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09
2025/07
国家科研体制的全新尝试——中科院数学院的成立
1998年中国科学院数学与系统科学研究院成立，不仅是我国数学史上的一个重要事件，也是我国科技史上的一个重要事件。本报告阐述了其成立的背景、成立过程中的主要改革举措以及产生的影响。一方面试图弄清这一事件的完整过程，一方面希望从中获取一些科学发展方面的经验和启示。
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11
2025/07
Groups as the automorphism groups of graphs and digraphs
In 1936, K?nig conjectured that every finite group can be represented as the automorphism group of a finite graph. This was answered in the affirmative by Frucht in 1939. Since then, this problem has been explored under various constraints on the graph. A particularly interesting case arises when the graph is vertex-transitive and has the same order as the group; such a graph is known as a Graphical Regular Representation (GRR). In the 1970s, a series of papers established which groups admit GRRs. In this talk I will first provide an overview of these classic results and then discuss some recent developments, including asymptotic enumeration, GRRs with specific valencies, and new variations of GRRs.
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07
2025/07
2025非交换几何暑期班与算子代数、算子理论研讨会
为加强同行之间的交流与合作，及时了解非交换几何、算子理论与算子代数等领域最新研究动态，深入探讨重要前沿课题，河北师范大学数学科学学院将于2025年7月7日至7月18日在河北省石家庄市召开非交换几何暑期班与算子代数、算子理论研讨会。暑期班课程名称：Dirac Operators Through the Lens of Operator Algebras暑期班课程简介：本系列课程以 Dirac 算子为核心，展示算子代数方法在表示论、几何与拓扑中的应用。课程将介绍群 K-理论、KK-理论与高指标理论的基本框架，并简要探讨 Connes–Kasparov 同构、Gromov–Lawson–Rosenberg 猜测与 Novikov 猜测等关键问题。通过这些主题，学员将体会非交换几何在刻画几何结构与拓扑不变量中的理论力量，并理解对偶性、局部化等核心思想在其中的具体体现。7月6日 报到7月7日8:00-8:30 开幕式8:30-9:30 主讲人：王航（华东师范大学）主题：群C*-代数及其K-理论（Baum-Connes猜测：使用几何算子计算）9:30-10:00 自由讨论10:00-11:00 主讲人：王航（华东师范大学）主题：K-理论、Bott周期性14:00-14:50 报告人：李玉成（河北师范大学）报告题目：Properties of a class of Hankel operators on generalized Fock space14:50-15:00 自由讨论15:00-15:50 报告人：原江涛（无锡学院）报告题目：From discriminant set to detectors15:50-17:00 自由讨论7月8日8:30-9:30 主讲人：刘泓志（上海财经大学）主题：Dirac算子简介9:30-10:00 自由讨论10:00-11:00 主讲人：刘泓志（上海财经大学）主题：Dirac算子与函数演算14:00-14:50 报告人：张远航（吉林大学）报告题目：On Products of symmetries acting on Hilbert spaces14:50-15:00 自由讨论15:00-15:50 报告人：辛悦（黑龙江大学）报告题目：Persistence modules induced by inner functions15:50-17:00 自由讨论7月9日8:30-9:30 主讲人：王航（华东师范大学）主题：椭圆算子、K-同调、KK-理论、高指标9:30-11:00 自由讨论14:00-14:50 报告人：李春光（东北师范大学）报告题目：Remarks on Villadsen algebras14:50-15:00 自由讨论15:00-15:50 报告人：马明辉（大连理工大学）报告题目：待定15:50-17:00 自由讨论7月10日8:30-9:30 主讲人：王航（华东师范大学）主题：Connes–Kasparov同构（表示论应用）9:30-11:00 自由讨论14:00-14:50 报告人：王晓峰（广州大学）报告题目：Bergman space with exponential weights on unit ball14:50-15:00 自由讨论15:00-15:50 报告人：赖旭东（哈尔滨工业大学）报告题目：Weak (1,1) bound for the noncommutative Calderon-Zygmund operator15:50-17:00 自由讨论7月11日8:30-9:30 主讲人：王航（华东师范大学）主题：正数量曲率与Gromov–Lawson–Rosenberg猜测简介（几何应用）9:30-11:00 自由讨论14:00-14:50 报告人：洪桂祥（哈尔滨工业大学）报告题目：待定14:50-15:00 自由讨论15:00-15:50 报告人：刘浏（大连理工大学）报告题目：Davis-Wielandt Shell15:50-17:00 自由讨论7月12日8:30-9:30 主讲人：王航（华东师范大学）主题：Dirac算子和bandwidth猜测（几何应用）9:30-11:00 自由讨论14:00-14:50 报告人：安庆楠（东北师范大学）报告题目：On the classification of 1-ASH algebras of real rank zero14:50-15:00 自由讨论15:00-15:50 报告人：吴恋（中南大学）报告题目：待定15:50-17:00 自由讨论7月13日 自由讨论7月14日 8:30-11:00 自由讨论14:00-14:50 报告人：王凯（复旦大学）报告题目：Some progress on the central limit theorem for Pfaffian point processes14:50-15:00 自由讨论15:00-15:50 报告人：冀姗姗（河北经贸大学）报告题目：The uniqueness of the irreducible decomposition of the Cowen-Douglas tuple up to unitary equivalence15:50-17:00 自由讨论7月15日8:30-11:00 自由讨论14:00-14:50 报告人：刘智超（大连理工大学）报告题目：On quasidiagonal algebras and quasidiagonal extensions14:50-15:00 自由讨论15:00-15:50 报告人：罗秋文（无锡学院）报告题目：The stable rank of a class of C* -algebras with the ideal property15:50-17:00 自由讨论7月16日8:30-11:00 自由讨论14:00-14:50 报告人：王利广（曲阜师范大学）报告题目：待定14:50-15:00 自由讨论15:00-15:50 报告人：徐景（河北地质大学）报告题目：On the flag structure and classification of the holomorphic curves on C*-Algebras15:50-17:00 自由讨论7月17日8:30-9:30 主讲人：刘泓志（上海财经大学）主题：局部化代数的K-理论与K-同调9:30-10:00 自由讨论10:00-11:00 主讲人：刘泓志（上海财经大学）主题：higher signature与Novikov猜测简介（拓扑应用）14:00-14:50 报告人：李建奎（华东理工大学）报告题目：待定14:50-17:00 自由讨论7月18日 8:30-9:30 报告人：郭坤宇（复旦大学）报告题目：待定9:30-10:00 自由讨论10:00-11:00 报告人：熊枭（哈尔滨工业大学）报告题目：待定14:00-17:00 自由讨论
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05
2025/07
文学院人才招聘暨青年学者论坛
韦志刚（中国社会科学院）：古代汉语中的第一人称代词。任天晓（复旦大学）：元明之际文坛之变。杨柳青（北京师范大学）：《诗》类佚文献学术价值举隅。闫学诗（清华大学）：《外国文学史》（高等教育出版社）探析。
