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    The aim of the present paper is to give some general surjectivity theorems for multifunctions using tangent cones and generalized differentiability assumptions.
    Tangent cone
    Citations (7)
    We prove a semistable version of the so-called p-adic Lefschetz (1, 1) theorem.As an application, we show a generalization of the Maulik-Poonen result on Picard number jumping locus. Introduction.Let K be a complete discrete valuation field of mixed characteristic (0, p) whose residue field k is perfect.Let X be a proper semistable model over S := Spec O K , X K be its generic fiber X ⊗ O K K, and Y be its special fiberwhere W is the ring of Witt vectors with coefficient k, and M Y and N 0 are logstructures on Y and Spec W respectively (the precise meaning of notations will be explained later).We also have Hyodo-Kato isomorphism ([HK])).This isomorphism depends on the choice of a uniformizer π ∈ K.However, we can show that ρ π (c crys ([L])) is independent of the choice of π (Corollary 2.3).In this paper, we first show the following generalization of the Berthelot-Ogus theorem ([BO, Theorem (3.8)]):Next, by using this theorem, we deduce a generalization of the Maulik-Poonen result ([MP]) (see Section 4 for precise meaning of the notations):
    Abstract Using Goursat’s lemma for groups, a simple representation and the invariant factor decompositions of the subgroups of the group Z m × Z n are deduced, where m and n are arbitrary positive integers. As consequences, explicit formulas for the total number of subgroups, the number of subgroups with a given invariant factor decomposition, and the number of subgroups of a given order are obtained.
    Lemma (botany)
    Rank (graph theory)
    Citations (16)