The symmetric monoidal structure on the category Sets of Proposition 5.5.9.1.1 is uniquely determined by the following requirements:

  1. 1. Two-Sided Preservation of Colimits. The tensor product
    Sets:Sets×SetsSets

    of Sets preserves colimits separately in each variable.

  2. 2. The Unit Object Is S0. We have 1SetsS0.

More precisely, the full subcategory of the category ME(Sets) of spanned by the symmetric monoidal categories (λSetsSets, Sets, 1Sets, λSets, ρSets, σSets) satisfying Item 1 and Item 2 is contractible.


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