Now showing items 1-6 of 6
Homology cobordism and Seifert fibered 3-manifolds
(American Mathematical Society, 2014)
It is known that every closed oriented 3-manifold is homology cobordant to a hyperbolic 3-manifold. By contrast we show that many homology cobordism classes contain no Seifert fibered 3-manifold. This is accomplished by ...
New Anomalous Lieb-Robinson Bounds in Quasiperiodic XY Chains
(American Physical Society, 2014)
We announce and sketch the rigorous proof of a new kind of anomalous (or sub-ballistic) Lieb-Robinson (LR) bound for an isotropic XY chain in a quasiperiodic transversal magnetic field. Instead of the usual effective light ...
Cubic fourfolds containing a plane and a quantic del Pezzo surface
(Foundation Compositio Mathematica, 2014)
We isolate a class of smooth rational cubic fourfolds X containing a plane whose associated quadric surface bundle does not have a rational section. This is equivalent to the nontriviality of the Brauer class β of the even ...
On the unirationality of del Pezzo surfaces of degree two
(London Mathematical Society, 2014)
Among geometrically rational surfaces, del Pezzo surfaces of degree 2 over a field k containing at least one point are arguably the simplest that are not known to be unirational over k. Looking for k-rational curves on ...
Cocycle rigidity and splitting for some discrete parabolic actions
(American Institute of Mathematical Sciences, 2014)