6 citations · 10 across the 9 of their papers we have counts for
11 papers
Unirational algebraic groups and tame ramification
Otto Overkamp, Ismaele Vanni
Let be a complete discrete valuation ring with field of fractions and algebraically closed residue field Let be a smooth connected commutative algebrai…
On Bosch-Lütkebohmert-Raynaud's Conjecture I
Otto Overkamp
Let be a smooth algebraic group over the field of rational functions of an excellent Dedekind scheme of equal characteristic A Néron lft-model of is a smooth sep…
Existence of global Néron models beyond semi-abelian varieties
Otto Overkamp, Takashi Suzuki
We first prove Bosch-Lütkebohmert-Raynaud's conjectures on existence of global Néron models of not necessarily semi-abelian algebraic groups in the perfect residue fields case. We…
Chai's conjectures on base change conductors
Otto Overkamp, Takashi Suzuki
The base change conductor is an invariant introduced by Chai which measures the failure of a semiabelian variety to have semiabelian reduction. We investigate the behaviour of this…
On logarithmic reduction of cohomologically tame elliptic surface
Otto Overkamp, Arne Smeets
We give cohomological criteria for logarithmic good reduction of elliptic surfaces up to modification. Along the way, we prove several more general results about such surfaces in p…
Chai's conjecture for semiabelian Jacobians
Otto Overkamp
We prove Chai's conjecture on the additivity of the base change conductor of semiabelian varieties in the case of Jacobians of proper curves. This includes the first infinite famil…
On Jacobians of geometrically reduced curves and their Néron models
Otto Overkamp
We study the structure of Jacobians of geometrically reduced curves over arbitrary (i. e., not necessarily perfect) fields. We show that, while such a group scheme cannot in genera…
Néron models of pseudo-Abelian varieties
Otto Overkamp
We study Néron models of pseudo-Abelian varieties over excellent discrete valuation rings of equal characteristic and generalize the notions of good reduction and semiabelian…
Degeneration of Kummer surfaces
Otto Overkamp
We prove that a Kummer surface defined over a complete strictly Henselian discretely valued field of residue characteristic different from 2 admits a strict Kulikov model after…
Jumps and motivic invariants of semiabelian Jacobians
Otto Overkamp
We investigate Néron models of Jacobians of singular curves over strictly Henselian discretely valued fields, and their behaviour under tame base change. For a semiabelian variety,…
Finite descent obstruction and non-abelian reciprocity
Otto Overkamp
For a nice algebraic variety over a number field , one of the central problems of Diophantine Geometry is to locate precisely the set inside $X(\A_F)$, where $\A_F$ d…