Contributed to the leanprover-community/mathlib4 repository by implementing an algebraic equivalence between rational function structures and fraction rings, specifically connecting RatFunc K with the fraction ring of K[X]. This work introduced the toFractionRingAlgEquiv mapping, leveraging existing equivalences to ensure that base-ring elements are mapped in a way that commutes with rational function construction. Using Lean and applying expertise in abstract algebra, algebraic geometry, and formal verification, the contribution enhanced the mathematical rigor and reusability of the library. The integration reinforced foundational algebraic layers, supporting future formalizations and proofs with improved interoperability across the Lean mathematical ecosystem.