How do you actually formally verify the code underpinning Ethereum's future?
In this episode (the finale of the
@leanEthereum miniseries),
@nico_mnbl sits down with Alex Hicks (
@alexanderlhicks), lead of Protocol Snarkification at the
@ethereumfndn, to break down formal verification from first principles.
They cover:
– What formal verification actually is and the trust boundaries between proof assistants, SMT solvers, and kernels
– The full verification stack for RISC-V ZKVMs: from SAIL specs to constraint extraction to soundness proofs
– Why writing constraints directly in Lean makes proofs 10–100x more ergonomic
– How AI is now proving hard theorems in hours for $200 — and what that unlocks for the whole pipeline
They also explore the boundaries problem, why specs can have bugs too, and the end goal of a full Lean stack that bypasses Rust and LLVM entirely.
Listen to the full episode
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TIMECODES:
09:16 – What is formal verification? Proof assistants vs SMT solvers
18:33 – Formal verification of code: specs, semantics, and trust boundaries
29:30 – Formally verifying the Lean Ethereum stack: RISC-V ZKVMs in focus
33:02 – Extracting ZKVM constraints into Lean and proving soundness
36:35 – Writing constraints directly in Lean: 10–100x better proof ergonomics
44:02 – Proving Polishchuk–Spielman in 8 hours for $200 with AI
51:01 – The end goal: a full Lean stack bypassing Rust and LLVM