Definition 21.3.5 (Relative slice category). For a functor \(F\colon C \to D\) and an object \(d\) of \(D\), we define the relative slice categories \(C_{/d}\) and \(C_{d/}\) via the following two pullback squares:
Objects of \(C_{/d}\) consist of pairs \((y,f\colon F(y) \to d)\), and objects of \(C_{d/}\) consist of pairs \((y,f\colon d\to F(y))\).
Generated from the authoritative LaTeX source.