Now showing items 21-30 of 45
Level structures on Abelian varieties, Kodaira dimensions, and Lang's conjecture
Assuming Lang's conjecture, we prove that for a prime p, number field K, and positive integer g, there is an integer r such that no principally polarized abelian variety A/K has full level-pr structure. To this end, we use ...
Cocycle rigidity and splitting for some discrete parabolic actions
(American Institute of Mathematical Sciences, 2014)
Filtering smooth concordance classes of topologically slice knots
We propose and analyze a structure with which to organize the difference between a knot in S3 bounding a topologically embedded 2–disk in B4 and it bounding a smoothly embedded disk. The n–solvable filtration of the ...
Log minimal model program for the moduli space of stable curves: the first flip
(Department of Mathematics, Princeton University, 2013)
We give a geometric invariant theory (GIT) construction of the log canonical model M¯g(α) of the pairs (M¯g,αδ) for α∈(7/10–ϵ,7/10] for small ϵ∈Q+. We show that M¯g(7/10) is isomorphic to the GIT quotient of the Chow variety ...
The Weil-Peterson Hessian of Length on Teichmuller Space
(International Press, 2012)
We present a brief but nearly self-contained proof of a formula for the Weil-Petersson Hessian of the geodesic length of a closed curve (either simple or not simple) on a hyperbolic surface. The formula is the sum of the ...
Failure of the Hasse Principle on General K3 Surfaces
(Oxford University Press, 2013)
We show that transcendental elements of the Brauer group of an algebraic surface can obstruct the Hasse principle. We construct a general K3 surface X of degree 2 over Q, together with a two-torsion Brauer class that is ...
The complex of partial bases for Fn and nite generation of the Torelli subgroup of Aut(Fn)
We study the complex of partial bases of a free group, which is an analogue for Aut(Fn) of the curve complex for the mapping class group. We prove that it is connected and simply connected, and we also prove that its ...
Hodge Theory and Lagrangian Planes on Generalized Kummer Fourfolds
(Independent University of Moscow, 2013)
Effective Computation of Picard Groups and Brauer-Manin Obstructions of Degree Two K3 Surfaces Over Number Fields
Using the Kuga-Satake correspondence we provide an effective algorithm for the computation of the Picard and Brauer groups of K3 surfaces of degree 2 over number fields.