Structure

Implication details

Claim: If a category has a generating collection and is locally essentially small, then it is concretizable.

Proof: If SS is a generating collection of a locally small category C\C, then by definition the functor (Hom⁡(G,−))G∈S:C→SetS(\Hom(G,-))_{G \in S} : \C \to \Set^S is faithful. Furthermore, the functor SetS→Set\Set^S \to \Set mapping X↦∐G∈SXGX \mapsto \coprod_{G \in S} X_G is faithful. Their composition provides a faithful functor C→Set\C \to \Set.

This implication has a dual.

Show 110 categories using this implication