Is the category of smooth manifolds equivalent to the opposite category of the category of commutative monoids of some additive symmetric monoidal category? - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-22T18:37:56Z http://mathoverflow.net/feeds/question/76868 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/76868/is-the-category-of-smooth-manifolds-equivalent-to-the-opposite-category-of-the-ca Is the category of smooth manifolds equivalent to the opposite category of the category of commutative monoids of some additive symmetric monoidal category? Dmitri Pavlov 2011-09-30T16:43:38Z 2011-09-30T16:43:38Z <p>This is a followup to my <a href="http://mathoverflow.net/questions/3323/recovering-a-monoidal-category-from-its-category-of-monoids" rel="nofollow">previous question</a>, which asked whether the category of commutative or noncommutative C*-algebras or von Neumann algebras is equivalent to the category of commutative or noncommutative monoids in some (symmetric) monoidal category. Tom Leinster gave a <a href="http://mathoverflow.net/questions/3323/recovering-a-monoidal-category-from-its-category-of-monoids/3356#3356" rel="nofollow">complete answer</a> for the commutative case, which turned out to be quite different from what I expected, because conditions on the underlying symmetric monoidal category were too weak.</p> <p>I want to revisit this question for the opposite category of the category of smooth manifolds, which is a full subcategory of the category of commutative real algebras. This time I want to consider only <em>additive</em> symmetric monoidal categories.</p> <p>I have in mind the classical example of the category of affine schemes, whose opposite category is equivalent to the category of commutative monoids of the category of abelian groups equipped with the standard tensor product.</p> <p>Perhaps the additive structure should be compatible with the symmetric monoidal structure, which is the case for the above example. I am somewhat hesitant to require the category to be preabelian or even abelian, but I would not mind an answer that uses one of these stronger conditions.</p> <p>For the category of smooth manifolds I expect the relevant additive symmetric monoidal category to be a subcategory of the category of complete locally convex nuclear Hausdorff topological vector spaces, possibly equipped with some additional structures, with the monoidal structure probably coming from the nuclear tensor product.</p> <p>I am also considering the option (communicated to me by Jeff Egger) that an involutive structure might be crucial in this setting, similarly to the case of C*-algebras and von Neumann algebras. Thus I am willing to replace monoids and categories with involutive monoids and involutive categories in the above description.</p> <p><strong>Is the category of smooth manifolds equivalent to the opposite category of the category of commutative (involutive?) monoids of some additive (involutive?) symmetric monoidal category?</strong></p> <p>I am also interested in the case of commutative C*-algebras and von Neumann algebras, as well as in the noncommutative case. Restricting to <em>compact</em> smooth manifolds is also possible.</p>