ICM 2026 Invited Section Lecture - Michael Wemyss

ICM 2026 Invited Section Lecture - Michael Wemyss

Formal & Physical Sciences Mathematics PBMathematics
🎙 Michael Wemyss 👥 61K 📅 October 5, 2026 ⏱ 41 min 👁 224 📄 expert opinion 🧭 2026-10-16
Available in: English (current) Français

Keywords

3-fold flopcontraction algebraclassificationnoncommutative singularity theoryderived category

Summary

This lecture presents the culmination of a 12-year project on the classification of 3-fold flops, a fundamental birational surgery in algebraic geometry. Michael Wemyss begins by explaining the concept with the simplest example, the Atiyah flop, illustrating how unique factorization failure leads to two non-isomorphic resolutions. He then introduces the minimal model program context, where flops connect non-unique minimal models. The central innovation is the use of contraction algebras, finite-dimensional noncommutative algebras associated to flopping contractions via noncommutative deformation theory. These algebras, derived from Donovan–Wemyss work, are curve invariants and control derived category symmetries. The main theorem, originally conjectured by Donovan–Wemyss and now proved by a chain of contributions (August, Kyung, Hua Keller, Wemyss–Carmazza–Lepri, Yasuo–Muro), states that 3-fold flops are classified by their contraction algebras. The classification strategy is described via a triple inclusion of sets (A⊂B⊂C⊂A), leading to both a full classification and an intrinsic characterization. The talk outlines the challenges of finding intrinsic properties, constructing examples, and highlights deep connections to Gopakumar–Vafa invariants, DT invariants, stability conditions, Cox theory, geometric group theory, cluster algebras, and representation theory.

179 words

Critical Evaluation

Value of the Information & Strength of the Argument

The value of the information is high, presenting the latest results in a challenging field. The argumentation is systematic: the speaker carefully introduces the objects, motivates the noncommutative approach, and demonstrates the logical flow of the classification strategy. The proof is not detailed but the logical structure is clear, making a compelling case for the importance and correctness of the main theorem. The talk is an expert synthesis of original work, not a survey of existing literature, which strengthens its value.

Scientific Rigor, Source Quality, Title Accuracy

The talk is rigorous, with clear definitions and careful justification of steps. The speaker cites his collaborators and key results, such as Van den Bergh’s derived equivalence theorem, without giving specific references in the transcript, but the context is academic and trustworthy. The title accurately describes the content. No external sources are listed in the description, so no additional sources can be evaluated. The mathematical reasoning is sound and based on published work, though the talk itself does not provide bibliographic details.

178 words

Title / Content Match

The title accurately reflects the content: an invited section lecture on the classification of 3-fold flops, presented by Michael Wemyss.

Quality & Reliability

9/10

Invited lecture at ICM 2026 by a leading researcher, based on a 12-year project with multiple collaborators. The talk is technically precise, introduces a novel classification theorem with a clear methodological framework, and is logically rigorous. The content is specialized and assumes advanced background, but it is internally coherent and well-argued.

Key Moments

Contribution & Novelties

The talk presents a new classification theorem for 3-fold flops via contraction algebras, which is a significant advance beyond previous numerical classifications. It provides both an intrinsic characterization and a constructive method, unifying many existing partial results. The noncommutative framework offers a novel perspective on birational geometry.

Pour aller plus loin :

  • Minimal model program — Central context where flops appear as elementary surgeries.
  • Derived category — Key tool used by Van den Bergh to relate geometric and algebraic data.
  • Gopakumar–Vafa invariants — Numerical invariants connected to flops and stability conditions.
  • Cluster algebra — Link via contraction algebras and cohomology modules.

101 words

Radar Profile

The profile shows extremely high levels of technical depth, information quantity, and internal quality, with only a moderate score for external sourcing due to the lack of references provided in the talk. The emphasis on original research and expert insight elevates the overall value.

Reliability 9/10