ScalingStacks

4. Outlook [03EG]

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4. Outlook

4.1. Combinatorics

It would be interesting to know whether the subdivision of |Σ||\Sigma| given by the F×F∨F\times F^{\vee} can be realized as the boundary of a dd-dimensional polytope (as the picture suggests). The dual of the face lattice would be given by the lattice of intervals in the face lattice of Δ\Delta (or of Δ∨\Delta^{\vee}).

In fact, if there was a realization of the combinatorial type of Δ\Delta with an identification ℝd≅(ℝd)∗\mathbb{R}^{d}\cong(\mathbb{R}^{d})^{*} such that the normal cones of FF and F∨F^{\vee} intersect in their relative interiors, then the Minkowski sum Δ+Δ∨\Delta+\Delta^{\vee} would do the trick. For d=3d=3, Koebe’s Theorem [Thu80] guarantees such a realization.

4.2. The Hausdorff convergence

There is a natural family of complex structures JsJ_{s} on the model torus fibration h:W→Σ\Dh\colon W\to\Sigma\backslash D. Namely, for a given ss we can take d​yi+−1log⁡|s|​d​θidy_{i}+\frac{\sqrt{-1}}{\log|s|}d\theta_{i} to be the holomorphic 1-forms on WW, where {yi}\{y_{i}\} are the affine coordinates on Σ\D\Sigma\backslash D and {θi}\{\theta_{i}\} are the corresponding coordinates on the torus fibers. Also, given a Riemannian metric ∑gi​j​d​yi⊗d​yj\sum g_{ij}dy_{i}\otimes dy_{j} on Σ\D\Sigma\backslash D, one can define the Kähler metric on WW by ωi​j=∑gi​j​(d​yi+−1log⁡|s|​d​θi)⊗(d​yj−−1log⁡|s|​d​θj)\omega_{ij}=\sum g_{ij}(dy_{i}+\frac{\sqrt{-1}}{\log|s|}d\theta_{i})\otimes(dy_{j}-\frac{\sqrt{-1}}{\log|s|}d\theta_{j}). If, in addition, gi​jg_{ij} satisfy the real Monge-Ampère equation: detgi​j≡1\det g_{ij}\equiv 1, then the induced metric on WW is Ricci-flat.

In the second part of the paper we will show that HssmH_{s}^{\mathrm{sm}} embeds into (W,Js)(W,J_{s}) “almost” holomorphically. Moreover, we will construct a family of 𝕋\mathbb{T}-invariant Kähler forms ωs\omega_{s} on XΔνX_{\Delta_{\nu}} in the class [ν]log⁡|s|\frac{[\nu]}{\log|s|}, such that the pairs (Hs,Hssing)(H_{s},H_{s}^{\mathrm{sing}}) with the induced metrics converge in the Gromov-Hausdorff sense to the pair (Σ,D)(\Sigma,D). Here Σ\Sigma will carry a compact metric space structure which will restrict to a Riemannian metric on Σ\D\Sigma\backslash D.

4.3. Non-Archimedean geometry

The family HsaffH^{\operatorname{af{}f}}_{s} can be thought of as an affine algebraic hypersurface in (K∗)d(K^{*})^{d} defined over a complete algebraically closed field KK that contains ℂ⁡((s))\mathbb{C}((s)). Then, as the name suggests, the image of HsaffH_{s}^{\operatorname{af{}f}} under the valuation map v​a​l:(K∗)d→Rdval:(K^{*})^{d}\to R^{d} will be the non-Archimedean amoeba 𝒜∞λ\mathcal{A}^{\lambda}_{\infty} (cf. [Kap00]).

Interestingly, the potential functions for our Kähler forms ωs\omega_{s} will come from smoothing a convex piecewise linear function on ℝd\mathbb{R}^{d}. This gives another evidence that there may be a reformulation of mirror symmetry purely in non-Archimedean terms. There is a partial understanding of this approach [Kon00], but the entire program still remains wide open.

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