"for each object A there is an arrow id_A called the identity of A whose source and target are both A."(adsbygoogle = window.adsbygoogle || []).push({});

wouldnt this definition imply that id_A is a point instead of an arrow?

if not help me visualise this.

btw this should be the notation id_A:A->A

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# Definiton of a category question

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