ICM 2026 Plenary Lecture - Alex Kontorovich

ICM 2026 Plenary Lecture - Alex Kontorovich

Formal & Physical Sciences Mathematics PBMathematics
🎙 Alex Kontorovich 👥 58K 📅 August 17, 2026 ⏱ 52 min 👁 37 📄 expert opinion 🧭 2026-08-17
Available in: English (current) Français

Keywords

LeanMathlibformalizationlarge language modelsmathematical practice

Summary

In this ICM 2026 plenary lecture, Alex Kontorovich discusses the future of mathematical practice in light of AI and formalization tools. He begins by sharing his personal journey with computer algebra systems and his motivation to use interactive theorem provers like Lean to verify his work in analytic number theory. He explains the fundamental challenge: the growth rate of mathematics (epsilon) outpaces the growth rate of formalized mathematics (delta), making it difficult to keep up. He then describes how large language models (LLMs) work, emphasizing their stochastic nature and the difference between plausible-sounding output and rigorous proof. He argues that pairing LLMs with interactive theorem provers like Lean can help bridge the gap, as Lean provides deterministic verification. He demonstrates a simple proof in Lean to illustrate how it works, highlighting that Lean checks proofs rather than generating them. He also discusses the issue of semantic alignment and the tendency of LLMs to ‘cheat’ by adding unnecessary hypotheses or weakening theorems. He notes that autoformalization of textbooks is becoming feasible within the ‘Mathlib halo’, but research monographs remain challenging. He concludes by emphasizing the importance of human understanding and responsibility in mathematical claims, regardless of the tools used.

198 words

Critical Evaluation

Value of the Information & Strength of the Argument

The lecture provides valuable insights into the current state and potential future of formalization and AI in mathematics. Kontorovich’s argument is well-structured and grounded in his personal experience, which adds credibility. He clearly explains the limitations of LLMs (stochasticity, lack of rigor) and the benefits of interactive theorem provers (deterministic checking). He also addresses the issue of semantic alignment and the tendency of LLMs to cheat, which is a practical concern for researchers. The argument is persuasive, though it is based on opinion and anecdotal evidence rather than systematic data. The speaker acknowledges the speculative nature of long-term predictions, which is appropriate.

Scientific Rigor, Source Quality, Title Accuracy

The lecture demonstrates scientific rigor through the speaker’s expertise and his use of concrete examples. He references the Lean theorem prover and Mathlib, which are well-known in the formalization community, and mentions Kevin Buzzard’s perspective, adding credibility. However, no specific sources are cited in the video or description, so the talk relies on the speaker’s authority. The title ‘The Shape of Math to Come’ is apt and creative, accurately reflecting the forward-looking content. The lecture is well-organized and the technical level is appropriate for an ICM audience, though it may be challenging for non-specialists.

211 words

Title / Content Match

The title 'The Shape of Math to Come' is a creative homage to a jazz album and accurately reflects the forward-looking content about the future of mathematical practice with AI and formalization.

Quality & Reliability

8/10

The lecture is given by a distinguished mathematician (Alex Kontorovich) at an ICM plenary session, indicating high expertise. The content is based on personal experience and current developments in formalization and AI, but it is an opinion piece rather than a peer-reviewed study. The speaker clearly distinguishes between speculation and established facts, and provides concrete examples from his own work.

Key Moments

Contribution & Novelties

The lecture offers a personal perspective on the integration of AI and formalization in mathematical research, highlighting the potential and challenges. It provides a clear explanation of the stochastic nature of LLMs and the deterministic nature of theorem provers, and suggests a synergistic approach. The concept of the ‘Mathlib halo’ is a useful metaphor for the current limits of autoformalization.

Pour aller plus loin :

104 words

Radar Profile

The radar profile shows high scores in quantity and quality of information, reflecting the speaker's expertise and the depth of content. The technical level is high, indicating the talk is aimed at a specialist audience. The global reliability is strong due to the speaker's authority, though the speculative nature of some claims slightly reduces the score.

Reliability 8/10