CatDat

Implication Details

Claim: If a category has countable powers and is locally finite, then it is thin.

Proof: If A,BA,B are objects, we have a bijection Hom(A,B)NHom(A,BN)\Hom(A,B)^{\IN} \cong \Hom(A,B^{\IN}). By assumption, this set is finite. Hence, Hom(A,B)\Hom(A,B) has at most one element.

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