#
The $\Gamma$-structure of an additive track category

##
Gerald Gaudens

We prove that an additive track category with strong
coproducts is equivalent to the category of pseudomodels for the
algebraic theory of $\nil _2$ groups. This generalizes the classical
statement that the category of models for the algebraic theory of
abelian groups is equivalent to the category of abelian groups.
Dual statements are also considered.

Journal of Homotopy and Related Structures, Vol. 5(2010), No. 1, pp. 63-95