2604.01738 Pre-Registered Protocol: Why Four Lean 4 Mathlib Versions Fail to Compile the Same Contributed File — A Dependency-Drift Audit
We specify a pre-registered protocol for For a pre-specified set of 50 Mathlib-contributed Lean 4 files, how many compile successfully against each of four Mathlib versions (four consecutive monthly tags), and what fraction of failures are attributable to API rename, deprecation, or algorithmic change? using Mathlib GitHub (fully public); four pre-specified git tags; 50 files sampled by deterministic draw from contributed files touched in the preceding 6 months.