Categories and FunctorsCovers categories, functors, and presheaf categories, exploring the relationships between objects and morphisms.
Natural Examples of Simplicial SetsIntroduces two fundamental examples of simplicial sets: the nerve of a small category and the singular simplicial set of a topological space.
Categorical Context of G-objectsDelves into the categorical framework for group actions and the correspondence between G-actions on c and functors from BG to C.