← Sunday, October 18, 2026Languages & toolsRelease

Lean adds sandboxed rechecking and four alternative proof kernels

leodemoura.github.io 3 min read Editor score 8/10

Lean 4.35.0 adds sandboxed `lake check`, four additional kernels, and a paranoid mode that rechecks developments across them. Multiple independent checks and hardened memory handling are useful patterns for software where a small trusted kernel matters.

What

Lean v4.35.0 adds lake check to export a development and recheck it with leanchecker inside a sandbox; it also ships four additional kernels.

How

lake check --paranoid rechecks developments with the additional kernels and a hardened variant of the official kernel.

Why it matters

Independent kernels and sandboxed rechecking add layers for detecting checker vulnerabilities and memory corruption in proof-validation systems.

Read on leodemoura.github.io → Hacker News · 26 comments

Headline, summary, brief and diagram are written by a model from the source's own text; the link, byline and numbers come from the source. Read the original before relying on a claim.