Episode 84 · The Machine's Theorems (Deep End, Ep 69–88), part 16 of 20
Shapes, Colours and Patterns: Convex Geometry and Combinatorics

Combinatorics is the part of mathematics where a twelve-year-old can understand the question and a professional can spend forty years on it. That makes it the perfect place to test what a machine-written proof is worth. Farah and Augustin colour the plane, squeeze convex bodies, hunt arithmetic progressions and tile space with a single strange block. Along the way we separate what OpenAI's manuscripts claim, what a Lean kernel has checked, and what the human community has actually said, including Joshua Swanson's verdict on the Shareshian–Wachs proof.
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Inside this episode
- Cold open: the coloured tiles on the floor
- Where we are, and the rules of the road
- Convex bodies: what a mathematician means by a nice shape
- Mahler's volume product: a shape and its shadow-twin
- What family eighty-seven claims, and what Lean checked
- Brunn–Minkowski, and its logarithmic cousin
- Borsuk in dimension nine: when cutting a shape into smaller pieces fails
- Colouring the plane: the five-colour wall
- Arithmetic progressions: Erdosh's dream and Szemerédi's ladder
- Sidorenko, van der Waerden, and other counterexamples
- Tiling space with one strange block
- Kazhdan–Lusztig and Shareshian–Wachs: algebraic combinatorics
- Inside a Lean check, said in words
- Why so many, and why combinatorics?
- The human cost, in Tao's words and Swanson's
- Why it matters for an engineer
- Ledger and closing
Production credits & AI disclosure
Scripts generated with Claude Opus. Synthetic narration generated with Edge TTS. Reviewed, listened to, and approved by Sankalp Thakur.