Zhao Yu-Yang contributed to the HuwCampbell/lean4 repository by streamlining the Init/GetElem.lean module, focusing on code cleanup to reduce unnecessary decidability assumptions in the getElem? and getElem! theorems. By leveraging the existing hypothesis h to imply the decidability of dom c i, Zhao removed redundant typeclass constraints, which improved code readability and maintainability without altering behavior or API guarantees. This work, rooted in formal verification and theorem proving, demonstrated a careful approach to simplifying Lean code while preserving proof obligations. The update enhanced the future refactorability of the codebase and reflected a thoughtful application of Lean’s type system.