Fixed Recursive Verifier

[sai-deng]

Summary
Implement a fixed verifier circuit for recursively verifying Plonky3 proofs. The circuit is a set of operation-specific STARK chips (Add/Mul/Sub, Merkle, FRI, etc.) wired via lookups to a central Witness bus. The Execution IR (a list of ops) is not proved—it only guides trace population. Soundness comes from each chip’s AIR + the aggregated lookups.

Why

• Smaller traces vs. a monolithic CPU
• Modular/extensible: add chips without changing the circuit skeleton
• Designed for cyclic recursion with a small recursion threshold

Full design doc: [link]

Comments welcome — please share feedback in this thread or the design doc.

[Nashtare]

I guess we can close this now that we have the mdbook running