Use when deciding whether a formalized proof should delegate to Mathlib, when refactoring standalone proofs into Mathlib wrappers, or when reviewing delegation refactors for correctness.
Use when running Stage 3.4 (Proof Polishing) to bring sorry-free proofs to Mathlib quality. Use when assessing whether a proof needs cleanup, when working through proof-polish GitHub issues, or when deciding which tactic to prefer for a given goal.
Use when a Lean proof has failed 2-3 attempts and needs to be sent to Aristotle for automated proving, or when checking the status of a previously submitted Aristotle job.
Quantitative insights on formalization speed by item type and proof strategy. Use when estimating difficulty from textbook statements, planning batches, or predicting project timelines.
Use when filling sorry placeholders in Lean 4 proof files, when choosing between proof approaches for a FormalFrontier item, or when a proof attempt fails and you need an alternative strategy.
Use when searching for Mathlib declarations to fill a proof, when imports fail, when you need to find the right Mathlib module for a concept, or when exact? or apply? don't find what you need.
Transferable lessons from the first complete FormalFrontier book formalization (Sutherland Number Theory Lecture 1). Use when planning or executing future book formalizations.
Use when CI fails on a PR, when debugging GitHub Actions failures, or when a PR is blocked by failing checks. Also use when planning work to fix broken PRs.