Structure

quotient object classifier

A category C\C has a quotient object classifier if its dual has a subobject classifier. This means that it has finite colimits and an epimorphism* ⊤:Ψ↠0\top : \Psi \twoheadrightarrow 0 such that for every epimorphism e:A↠Be : A \twoheadrightarrow B there is a unique morphism ψe:Ψ→A\psi_e : \Psi \to A such that Ψ→⊤0ψe↓↓!A→eB\begin{CD} \Psi @>{\top}>> 0 \\ @V{\psi_e}VV @VV{!}V \\ A @>>{e}> B \end{CD} is a pushout diagram. Equivalently, the functor Quot⁡:C→Set+\Quot : \C \to \Set^+ is representable. *Every morphism Ψ→0\Psi \to 0 is a split epimorphism anyway.

Relevant implications

Examples

There are 4 categories with this property.

Counterexamples

There are 131 categories without this property.

Unknown

There are 0 categories for which the database has no information on whether they satisfy this property.

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