ScalingStacks

In the case of a large complex structure limit, dimℝS​k​(𝒳)=n\dim_{\mathbb{R}}Sk(\mathcal{X})=n. Let us analyze the CY measure more explicitly, in a semistable snc model. For EJE_{J} corresponding to an nn-dimensional simplex in S​k​(𝒳)Sk(\mathcal{X}), on EJ0E_{J}^{0}

−1n2​Ωt∧Ω¯t=|uJ|2​∏1n−1​d​log⁡zi∧d​log⁡z¯i.\sqrt{-1}^{n^{2}}\Omega_{t}\wedge\overline{\Omega}_{t}=|u_{J}|^{2}\prod_{1}^{n}\sqrt{-1}d\log z_{i}\wedge d\log\bar{z}_{i}. (7)

Here uJu_{J} limits to its value uJ​(EJ)u_{J}(E_{J}) at the point stratum EJE_{J}, which is called the Poincaré residue of Ω\Omega, and is easily seen to be independent of the choice of coordinates ziz_{i}. It is a consequence of the residue theorem on Riemann surfaces that |uJ​(EJ)|2|u_{J}(E_{J})|^{2} is independent of such JJ [3, Thm. 7.1]. Thus the pushforward to Δ𝒳\Delta_{\mathcal{X}} of the normalised CY measure (5) converges smoothly in the interior of ΔJ\Delta_{J} to a constant multiple of the Lebesgue measure:

Log𝒳∗dμt=Log𝒳∗Ωt∧Ω¯t∫XtΩt∧Ω¯t→t→0dμ0:=Const⋅dx1…dxn.\text{Log}_{\mathcal{X}*}d\mu_{t}=\text{Log}_{\mathcal{X}*}\frac{\Omega_{t}\wedge\overline{\Omega}_{t}}{\int_{X_{t}}\Omega_{t}\wedge\overline{\Omega}_{t}}\xrightarrow{t\to 0}d\mu_{0}:=\text{Const}\cdot dx_{1}\ldots dx_{n}. (8)

Notice d​x1​…​d​xndx_{1}\ldots dx_{n} is canonically defined due to the presence of an integral affine structure on ΔJ\Delta_{J}. Viewed as a measure on Δ𝒳\Delta_{\mathcal{X}}, the limit d​μ0d\mu_{0} has null measure on the complement of the nn-dimensional faces of S​k​(𝒳)Sk(\mathcal{X}), as the integral of d​μtd\mu_{t} in the corresponding region is O⁡(1|log⁡|t||)O(\frac{1}{|\log|t||}). The constant in (8) is independent of JJ and its sole purpose is to make d​μ0d\mu_{0} a probability measure.

Original mathematics by the credited authors. Source collection and HTML conversion remain in progress.