Category theory

Bicategories and their adjunctions; ordinary categories, limits, abelian and monoidal categories; the pointwise shift on a functor category; t-structures, dg enhancements, Cat-valued pseudofunctors, neutral moduli interfaces, site-theoretic sheaves, and the categorical foundations of Bridgeland stability conditions. Derived categories, the homotopy category, spectral sequences, and dg categories extend Mathlib's homological algebra and live under Algebra/Homology/.