The characteristic-cycle pullback conjecture for log-clean ramification

From papers

Suppose that XX is purely of dimension dd and that DD has simple normal crossings. Let III'\subset I be a subset containing IT,FI_{\mathrm{T},\mathcal{F}}, and let

D=iIDi.D'=\bigcup_{i\in I'}D_i.

Assume that the ramification of F\mathcal{F} is log\log-DD'-clean along DD, and that the inverse image

τD1(SDlog(j!F))TX\tau_{D'}^{-1}\bigl(S_{D'}^{\log}(j_{!}\mathcal{F})\bigr)\subset T^*X

of the log\log-DD'-singular support SDlog(j!F)TX(logD)S_{D'}^{\log}(j_{!}\mathcal{F})\subset T^*X(\log D') by the canonical morphism τD\tau_{D'} is of dimension dd. Characteristic-cycle pullback conjecture. Then

CC(j!F)=τD!CCDlog(j!F)CC(j_{!}\mathcal{F})=\tau_{D'}^{!}CC_{D'}^{\log}(j_{!}\mathcal{F})

in Zd(τD1(SDlog(j!F)))Z_d\bigl(\tau_{D'}^{-1}(S_{D'}^{\log}(j_{!}\mathcal{F}))\bigr), where τD!\tau_{D'}^{!} is the indicated Gysin map. This conjecture predicts that, under the stated cleanliness and dimension hypotheses, the ordinary characteristic cycle is obtained from the logarithmic characteristic cycle by pullback; its status is not established by the supplied text.

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Sources & referencesView supporting material

Primary source

Yuri Yatagawa, “Singular support and Characteristic cycle of a rank one sheaf in codimension two”, arXiv:2206.02989 (2022).

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