Structure

Implication details

Claim: If a category is one-way and has zero morphisms, then it is thin.

Proof: If f,g:A⇉Bf,g : A \rightrightarrows B are two morphisms, then since 0B,B=idB0_{B,B} = \id_B we have f=0B,B∘f=0A,B=0B,B∘g=g.f = 0_{B,B} \circ f = 0_{A,B} = 0_{B,B} \circ g = g.
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