Structure

Implication details

Claim: If a category has disjoint finite coproducts and is regular-subobject-trivial, then it is trivial.

Proof: For any object XX, the unique morphism !:0→X! : 0 \to X is a regular monomorphism, as the equalizer of the two coprojections X⇉X⊔XX \rightrightarrows X \sqcup X. Therefore, it is an isomorphism.

This implication has a dual.

Show 31 categories using this implication