FFP EP. 21 | Roman Concrete, Brain “Cognitive Legos,” DeepSeek, and Econophysics

Hosted by Lester Nare and Krishna Choudhary, this episode jumps from ancient engineering to modern AI and markets. We start with the newly uncovered Pompeii worksite that finally shows how Romans mixed their concrete — and why it “self-heals.” Then we pivot into a Princeton neuroscience idea that the brain builds complex thought like LEGO bricks (compositional neural subspaces). From there, we break down DeepSeek’s “manifold-constrained hyperconnections” as a stability mechanism for scaling deep nets. And we close with econophysics: a Physical Review Letters result arguing the square-root law of market impact is strictly universal across stocks and time.

Summary

• Roman concrete’s missing step — Pompeii evidence for “hot mixing,” lime clasts, and why cracks can heal themselves for millennia.
• Cognitive LEGOs — a compositionality framework where brains reuse shared neural subspaces to assemble new tasks.
• DeepSeek’s scaling trick — constraining hyperconnections to a stable manifold to avoid vanishing/exploding signals.
• The universal market law — PRL evidence that price impact follows a square-root rule across stocks, traders, and decades.
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Show Notes

• ⁠Roman Concrete (Pompeii worksite) — Nature Communications (2025)⁠
• ⁠Hot Mixing & Lime Clasts — Science Advances (2023)⁠
• ⁠Compositional Neural Subspaces (“Cognitive LEGOs”) — Nature (2025)⁠
• ⁠mHC: Manifold-Constrained Hyper-Connections — arXiv⁠
• ⁠Square-Root Law of Market Impact (Universality) — Physical Review Letters⁠
• ⁠Artemis II Countdown Demonstration Test — NASA