During two months, Sifeng developed advanced algebraic formalizations in Lean, focusing on module localization and homomorphism equivalences. In the CohenMacaulay repository, Sifeng introduced foundational features for localized modules, formalized properties of mappings, and enhanced the robustness of associated primes and ideal unions. The work included defining injectivity and bijectivity conditions for localized module mappings, as well as extending lemma support for nontrivial cases. In mathlib4, Sifeng expanded the Algebra module to support localized homomorphism equivalences for finitely presented modules, clarifying relationships between localized structures. The work demonstrated depth in abstract algebra, commutative algebra, and formal verification.