Now showing items 1-6 of 6
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 ...
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 ...
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 ...
Cocycle rigidity and splitting for some discrete parabolic actions
(American Institute of Mathematical Sciences, 2014)
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 ...