Counting augmentations

In Conjecture 7.5 of [STZ], we hypothesized that, for $\Lambda$ a Legendrian knot in the standard 3-space, the following were equal over any finite field: (1) The groupoid cardinality of the augmentation category (2) The groupoid cardinality of the category of rank 1 sheaves on $\Lambda$ (3) The raw number of augmentations, times some fudge factor …

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Re: Nadler-Zaslow without Floer theory

The following is a comment to David’s post “Nadler-Zaslow without Floer theory”. There was some error posting it as a comment probably because it is too long, so I turn it into a post. Based on David’s comment about specializations, I think the following categorical calculations of Floer cohomology (and higher $A_\infty$-structures) should work, though …

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Discussions with Davide

After my talk at the Berkeley math/physics meeting, I talked a little with Davide Gaiotto.  This resulted in the following compelling pictures which I do not actually understand: Say you have a spectral network and a spectral curve.  There’s an exact Lagrangian naturally associated to this data: each line of the spectral network comes labelled with …

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Are there interesting legendrians at infinity in the cotangent space of bundles?

A question from Laura Schaposnik: If you have a 3-manifold $M$ with boundary in a surface $S$, you get a holomorphic Lagrangian $Loc(M) \subset Loc(S)$.  Translate over to the Hitchin system, you have a usual Lagrangian inside $T^* Bun_G(S)$.  Now forget the Lagrangian and just remember its asymptotics, $\Lambda$.  What’s the meaning of $Sh_{\Lambda}(Bun_g(S))$? I …

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Nadler-Zaslow without Floer theory

Theorem. (Nadler-Zaslow) Let $L \subset T^* M$ be an exact Lagrangians, whose brane obstructions are trivial, and that is subject to certain tameness conditions.  Then there is a functor from local systems of $\mathbf{C}$-vector spaces on  $L$ to constructible sheaves on $M$. The functor is well-defined up to a shift and signs, coming from the …

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Monodromy

Investigating the monodromy of the rank-two sheaf microlocal dual to the complex Lagrangian brane $L = \{y = \pm \sqrt{x}\} \subset T^*\mathbb C_x$, we follow the family $hom_{Fuk}(L,T^*_{x = e^{2\pi i t}}\mathbb C)$ of cochain complexes as $t$ goes from $0$ to $1.$  To compute, we turn our heads and consider that $L = \{ …

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Toric Stuff

Summary of discussion with David the other night – let me know if anything sounds wrong: Claim: Let $\Sigma \subset N_\mathbb{R} \cong \mathbb{R}^2$ be a complete fan, $\Lambda_\Sigma \subset T^* (M_\mathbb{R}/M)$ the associated Lagrangian, and $n \in N_\mathbb{R}$. Let $\mu_n: Sh_{cc}(M_\mathbb{R}/M, \Lambda_\Sigma) \to dg-Vect$ take a sheaf to its microstalk at $(M,n)$. If $-n$ is …

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Axiomatics of the augmentation category

Let $X$ be a manifold.  I am going to sketch some axiomatics the big augmentation category $\mathcal{A}(X)$ of Legendrians in the jet space $J^1(X)$.  These will certainly be satisfied by the “straightforward generalization” of the category we defined in the “augmentations are sheaves” paper.  I’ll show such a category always has a morphism to the sheaf category, and reduce showing …

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