Structure

Implication details

Claim: Given a functor whose codomain is trivial, and whose domain is inhabited, then it is right-invertible.

Proof: Let C\C be an inhabited category and let F:C→1F : \C \to 1 be the unique functor to the trivial category. Choose any object X∈CX \in \C. Then the constant functor X:1→CX : 1 \to \C satisfies F∘X=id1F \circ X = \id_1.
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