219 research outputs found

    Morphisms of Berkovich curves and the different function

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    Given a generically \'etale morphism f ⁣:YXf\colon Y\to X of quasi-smooth Berkovich curves, we define a different function δf ⁣:Y[0,1]\delta_f\colon Y\to[0,1] that measures the wildness of the topological ramification locus of ff. This provides a new invariant for studying ff, which cannot be obtained by the usual reduction techniques. We prove that δf\delta_f is a piecewise monomial function satisfying a balancing condition at type 2 points analogous to the classical Riemann-Hurwitz formula, and show that δf\delta_f can be used to explicitly construct the simultaneous skeletons of XX and YY. As an application, we use our results to completely describe the topological ramification locus of ff when its degree equals to the residue characteristic pp.Comment: Final version, 49 pages, to appear in Adv.Mat

    Jumps and monodromy of abelian varieties

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    We prove a strong form of the motivic monodromy conjecture for abelian varieties, by showing that the order of the unique pole of the motivic zeta function is equal to the size of the maximal Jordan block of the corresponding monodromy eigenvalue. Moreover, we give a Hodge-theoretic interpretation of the fundamental invariants appearing in the proof.Comment: Section 5 rewritten, Section 6 expande
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