
Duality for Groups (1950) - mikorym
https://projecteuclid.org/download/pdf_1/euclid.bams/1183515045
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mikorym
This is an early paper by Mac Lane that lead to interesting results (such as
abelian categories) and paved the way for the notion of categorical duality in
early category theory.

Interestingly, he did not cover the case of (not necessarily abelian) groups
and attempting to phrase the category of groups in self-dual terms necessarily
would lead to additional structure on the category.

Nevertheless, the abelian case turned out to lead to the whole field of
abelian categories as studied by many great mathematicians (such as
Grothendieck). This paper is one of the earliest full exhibitions of how to
approach duality in the category theoretic sense.

