Esnault–Kerz conjecture on curvewise computation of the Swan divisor

About 9 years old · traced to

Let XX be a normal κ\kappa-scheme of finite type, let DD be an integral effective Cartier divisor with smooth complement U=X−DU=X-D, and let j:U→Xj:U\rightarrow X be the canonical injection. Let F\mathscr F be a locally constant constructible sheaf of Λ\Lambda-modules on UU, and let C(X)\mathcal C(X) be the set of canonical morphisms g:C~→Xg:\widetilde C\rightarrow X from normalizations of suitable one-dimensional integral closed subschemes. Define PC(X)\mathcal{PC}(X) as the set of pairs (g:C~→X,x)(g:\widetilde C\rightarrow X,x) with g∈C(X)g\in\mathcal C(X) and xx a closed point of g∗Dg^*D. Write mx(g∗D)m_x(g^*D) for the multiplicity of g∗Dg^*D at xx, and let swD(j!F)\mathrm{sw}_D(j_!\mathscr F) be the coefficient of the Swan divisor after replacing XX by a smooth open neighborhood of the generic point of DD.

Esnault–Kerz conjecture. One has

sup⁡PC(X)swx(g∗j!F)mx(g∗D)=swD(j!F).\sup_{\mathcal{PC}(X)}\frac{\mathrm{sw}_x(g^*j_!\mathscr F)}{m_x(g^*D)}=\mathrm{sw}_D(j_!\mathscr F).

The conjecture asserts that the generic coefficient of the Swan divisor is recovered exactly as the supremum of normalized curvewise Swan conductors. It is the sharp curve-restriction formulation of the logarithmic ramification prediction described in the source.

References

Primary source

Haoyu Hu, “Logarithmic ramifications of étale sheaves by restricting to curves”, arXiv:1704.04734 (2017).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.