Authors: Joël Riou ¹

• 1 Université Paris-Saclay

This paper outlines the formalization of derived categories in the mathematical library of the proof assistant Lean 4. The derived category D(C) of any abelian category C is formalized as the localization of the category of unbounded cochain complexes with respect to the class of quasi-isomorphisms, and it is endowed with a triangulated structure.