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Dec 13, 2021 at 10:13 comment added Jon Pridham The point is that $X(k)$ is the only connected space; the spaces $X(A)$ for Artinian rings are not, unless the DGLA in concentrated in non-positive cochain degrees. Contrast this with the notation $BG$ for the stack of $G$-torsors, whose stalks are connected in the sense that $(BG)(A)= B(G(A))$ for any Henselian ring $A$.
Dec 13, 2021 at 0:18 comment added A Rock and a Hard Place @JonPridham: Agreed! But I don't quite see why this objection applies to the case at hand. (Pardon if I am missing something!) One of the requirements in the definition of a formal moduli problem is that $X(k)$, which may be thought of as the space of $k$-valued points of $X$, must be contractible. So $X$ has only a single "object", at least up homotopy (which is the best we can ask for anyway). On the other hand, Gaitsgory-Roseblyum also have a version of the correspondence between Lie algebroids and some kind of multi-object FMPs, where the objection to using $B$ might well be applicable.
Dec 11, 2021 at 23:50 comment added Jon Pridham Reiterating a comment I made on the question, BG is not good notation for an infinitesimal functor with many objects (essentially the Deligne groupoid in this case).
Aug 28, 2020 at 10:08 history edited A Rock and a Hard Place CC BY-SA 4.0
corrected typo
Apr 2, 2020 at 14:22 history edited A Rock and a Hard Place CC BY-SA 4.0
Added discussion of group objects in E_n-FMPs
Mar 3, 2020 at 2:33 comment added Dmitry Vaintrob Thanks! This is a funny property, that the delooping functor is an equivalence but the category is not stable. I wonder if there are other examples. And thanks for the correction: $E_n$ moduli problems are represented by $E_n$ algebras via a duality functor, so presumably a group object (in a geometric sense) would be representable by an $E_{n+1}$ algebra.
Mar 3, 2020 at 2:31 vote accept Dmitry Vaintrob
Mar 2, 2020 at 3:02 history edited A Rock and a Hard Place CC BY-SA 4.0
Unifying notation
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Mar 1, 2020 at 20:40 history edited A Rock and a Hard Place CC BY-SA 4.0
Adding a little more details
Mar 1, 2020 at 6:22 history edited A Rock and a Hard Place CC BY-SA 4.0
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Mar 1, 2020 at 5:55 history edited A Rock and a Hard Place CC BY-SA 4.0
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Mar 1, 2020 at 5:40 history answered A Rock and a Hard Place CC BY-SA 4.0