Now showing items 1-10 of 13
The second rational homology group of the moduli space of curves with level structures
Let Γ be a finite-index subgroup of the mapping class group of a closed genus g surface that contains the Torelli group. For instance, Γ can be the level L subgroup or the spin mapping class group. We show that H2(Γ;Q) ∼= Q ...
Higher-Order Signature Cocycles for Subgroups of Mapping Class Groups and Homology Cylinders
(Oxford University Press, 2012)
The Picard group of the moduli space of curves with level structures
For 4 - L and g large, we calculate the integral Picard groups of the moduli spaces of curves and principally polarized abelian varieties with level L structures. In particular, we determine the divisibility properties of ...
The Density of States Measure of the Weakly Coupled Fibonacci Hamiltonian
We consider the density of states measure of the Fibonacci Hamiltonian and show that, for small values of the coupling constant V , this measure is exact-dimensional and the almost everywhere value dV of the local ...
Opening gaps in the spectrum of strictly ergodic Schrodinger operators
(European Mathematical Society, 2012)
We consider Schrodinger operators with dynamically defined potentials arising from continuous sampling along orbits of strictly ergodic transformations. The Gap Labeling Theorem states that the possible gaps in the spectrum ...
Higher-dimensional analogs of Chatelet surfaces
(London Mathematical Society, 2012)
We discuss the geometry and arithmetic of higher-dimensional analogs of Chatelet surfaces; namely, we describe the structure of their Brauer and Picard groups and show that they can violate the Hasse principle. In addition, ...
Handle Addition for Doubly-Periodic Scherk Surfaces
(De Gruyter, 2012)
We prove the existence of a family of embedded doubly periodic minimal surfaces of (quotient) genus g with orthogonal ends that generalizes the classical doubly periodic surface of Scherk and the genus-one Scherk surface ...
A Birman exact sequence for Aut(Fn)
The Birman exact sequence describes the effect on the mapping class group of a surface with boundary of gluing discs to the boundary components. We construct an analogous exact sequence for the automorphism group of a free ...
Small generating sets for the Torelli group
(Mathematical Sciences Publisher, 2012)
Proving a conjecture of Dennis Johnson, we show that the Torelli subgroup Ig of the genus g mapping class group has a finite generating set whose size grows cubically with respect to g. Our main tool is a new space called ...