This question resolves based on the total number of lines of code (LOC) in the Lean mathlib repository.

As of late 2025, mathlib contains approximately 2.1 million lines of code across roughly 8,000 files. Over the past two years, growth has been approximately linear, which (if extrapolated) would not reach 10 million LOC by 2030.

Therefore, a “Yes” outcome implies a substantial acceleration in the rate of formalization, potentially driven by improved tooling, automation, or AI-assisted proof generation.

Resolution criterion:
This question resolves Yes if the official mathlib statistics report more than 10,000,000 total lines of code at any point on or before December 31, 2030. Otherwise, it resolves No.

Primary source:

https://leanprover-community.github.io/mathlib_stats.html