Sam Raskin - 4/6 Some Aspects of the Geometric Langlands Program

Sam Raskin - 4/6 Some Aspects of the Geometric Langlands Program

🎙 Sam Raskin 👥 79K 📅 March 16, 2026 ⏱ 120 min 👁 789 📄 lecture 🧭 2026-08-02
Available in: English (current) Français

Keywords

geometric Langlandsde RhamD-modulescategorical localizationEisenstein series

Summary

In this fourth lecture of a series, Sam Raskin outlines the proof of the geometric Langlands conjecture in the de Rham setting, focusing on the role of categorical localization at the critical level. He recalls the spectral action of quasi-coherent sheaves on the category of D-modules on the stack of G-bundles, and introduces the Langlands functor and the algebra A_G. Under simplifying assumptions (G adjoint, genus ≥2), he states three key inputs proved via categorical localization: (1) A_G restricted to the locus of reducible local systems is an isomorphism; (2) A_G on the irreducible locus is a perfect complex; (3) it admits a flat connection with regular singularities. He explains the nature of these statements, particularly the subtlety of compatibility with constant terms, contrasting it with the easier Eisenstein series compatibility. He discusses the heuristic principle that the general theory is effective for computing homs between distinct classes of objects, and highlights the difference between the de Rham and Betti settings. He also addresses a question about generalizing to reductive group schemes over the curve, noting that over an algebraically closed field every such group is quasi-split, so new phenomena may be limited. The lecture is highly technical, aimed at researchers, and includes references to ongoing work by Gaitsgory, Chen, and Lin.

212 words

Critical Evaluation

This lecture provides a high-level overview of the proof of the geometric Langlands conjecture in the de Rham setting, with a focus on the role of categorical localization. The speaker, Sam Raskin, is a leading expert in the field, and the content reflects current research, including his own contributions. The presentation is rigorous and assumes a strong background in algebraic geometry and representation theory. The argument is structured around three key inputs derived from categorical localization, and Raskin explains the conceptual role of each, particularly the subtlety of compatibility with constant terms. He also provides a heuristic principle for when the general theory is effective, which is valuable for researchers. The lecture is part of a series at IHES, ensuring high scientific standards. However, the content is extremely specialized and not accessible to non-experts. The description provides no external sources beyond the Carmin.tv platform, but the speaker’s authority and the institutional context support the reliability. The title accurately reflects the content. The lecture does not include any advertising or sponsorship. Overall, this is an excellent resource for researchers in the field, though its narrow focus limits its broader appeal.

189 words

Title / Content Match

The title accurately reflects the content: a lecture on aspects of the geometric Langlands program, specifically focusing on the proof in the de Rham setting.

Quality & Reliability

8/10

Lecture by a leading expert (Sam Raskin, Yale) at IHES, part of a series on the geometric Langlands program. Content is highly technical and based on recent research, with references to ongoing work and collaborations. The presentation is rigorous, though it assumes advanced background. No sources are cited in the description beyond the Carmin.tv platform, but the speaker's authority and the institutional setting support high reliability.

Key Moments

Cited Sources

  • Carmin.tv — Video platform hosting the lecture, mentioned in the description.

Concurring Sources

  • Carmin.tv — Platform hosting the lecture, consistent with the institutional context.

Contribution & Novelties

This lecture provides an expert overview of recent progress on the geometric Langlands conjecture, specifically the proof in the de Rham setting. It highlights the role of categorical localization at the critical level, which is a key technique in the proof. The lecture also clarifies the conceptual role of the three main inputs derived from categorical localization, and contrasts the de Rham and Betti settings. This is valuable for researchers seeking to understand the structure of the proof.

Pour aller plus loin :

125 words

Radar Profile

The radar profile shows very high scores in technical level and information quality, reflecting the advanced and rigorous nature of the lecture. The quantity of information is also high, but the global reliability is slightly lower due to the lack of external sources cited. Overall, this is a highly specialized and reliable resource for experts.

Reliability 8/10