Hey all,

So I’ve been kind of bugging out trying to find some kind of coherent theory of comonoids in $\infty$-categories. This, for instance, would apply to comonads (as co-associative comonoids in endomorphism categories) among other things. When I try to use Lurie’s stuff, I end up having to trace further and further back to try to prove anything, and end up feeling like I need a theory of cooperads. Somehow comonoid structures seem fundamentally different than monoid structures. Does anyone know how to do this, or if it’s written down clearly anywhere? For instance, Lurie has this nice theorem in one of the DAGs where he shows that monoids are essentially simplicial objects, and this seems to generalize pieces of Emily Riehl’s work with Dominic Verity, except for the fact that there’s no analog for comonoidal objects. It’d be nice to have the analogous statement saying that comonoids are cosimplicial objects in some essential way.

Thanks for any ideas!

-Jon

]]>Hi,

I would like to contribute to the nLab page on state spaces. In particular I would like to build up to this through a particular route, for which I will need some help. I have been trying to build a notion of state space out of a monad. I have found a paper where a state space is built from a comonad. The paper in particular is Vicary’s work on the quantum harmonic oscillator. The adjunction $F = RQ$ in section 4.1, he calls a state space for multi-particle system or Fock space. This $F$ is a comonad. I guess, in short, could we put up an article for comonads as state spaces?

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