Structure

Implication details

Claim: If a category is one-way, then it has reflexive coequalizers.

Proof: The two morphisms of every reflexive pair are equal: If fs=gs=idf s = g s = \id, then sf=ids f = \id since the category is one-way, so we must have f=s−1f = s^{-1}, and likewise g=s−1g = s^{-1}.

This implication has a dual.

Show 13 categories using this implication