A concrete category is a category C together with a function that assigns to each object A of C a set called the underlying set of A.
Example: The category of groups, equipped with the function that assigns to each group its underlying set in the usual sense, is a concrete category.
What is the underlying set for an object in a category of groups ?
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closed as no longer relevant by Jonas Meyer, Robin Chapman, Qiaochu Yuan, Pete L. Clark, José FigueroaO'Farrill Aug 9 '10 at 20:11This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. If this question can be reworded to fit the rules in the help center, please edit the question. 


The underlying set for an object in the category of groups is just the underlying set of the group, there is no other name for it. 

