For every group G, we construct a functor F : SET --> SET (finitary for a finite group G) such that the monoid of all natural endotransformations of F is a group isomorphic to G.
Keywords: set functor, group universal category
2000 MSC: 18B15
Theory and Applications of Categories,
Vol. 14, 2005,
No. 13, pp 294-309.
http://www.tac.mta.ca/tac/volumes/14/13/14-13.dvi
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