Densities of 4-ranks of K2(O)K_2(\mathcal{O})

Conner and Hurrelbrink established a method of determining the structure of the 2-Sylow subgroup of the tame kernel $K_2(\mathcal{O})$ for certain quadratic number fields. Specifically, the 4-rank for these fields was characterized in terms of positive definite binary quadratic forms. Numerical calculations led to questions concerning possible density results of the 4-rank of tame kernels. In this paper, we succeed in giving affirmative answers to these questions.Comment: 11 page

Vanishing of eigenspaces and cyclotomic fields

We use a result of Thaine to give an alternative proof of the fact that, for a prime p>3 congruent to 3 modulo 4, the component e_{(p+1)/2} of the p-Sylow subgroup of the ideal class group of \mathbb Q(\zeta_{p}) is trivial.Comment: 6 pages, minor corrections made, to appear in the International Mathematics Research Notice

A remark on a conjecture of Borwein and Choi

We prove the remaining case of a conjecture of Borwein and Choi concerning an estimate on the square of the number of solutions to n=x^2+Ny^2 for a squarefree integer N.Comment: 7 pages, to appear in Proc. Amer. Math. So

Congruences for traces of singular moduli

We extend a result of Ahlgren and Ono on congruences for traces of singular moduli of level 1 to traces defined in terms of Hauptmodul associated to certain groups of genus 0 of higher levels.Comment: 8 pages, to appear in The Ramanujan Journa

A note on 4-rank densities

For certain real quadratic number fields, we prove density results concerning 4-ranks of tame kernels. We also discuss a relationship between 4-ranks of tame kernels and 4-class ranks of narrow ideal class groups. Additionally, we give a product formula for a local Hilbert symbol.Comment: 9 page

M_2-rank differences for overpartitions

This is the third and final installment in our series of papers applying the method of Atkin and Swinnerton-Dyer to deduce formulas for rank differences. The study of rank differences was initiated by Atkin and Swinnerton-Dyer in their proof of Dyson's conjectures concerning Ramanujan's congruences for the partition function. Since then, other types of rank differences for statistics associated to partitions have been investigated. In this paper, we prove explicit formulas for M_2-rank differences for overpartitions. Additionally, we express a third order mock theta function in terms of rank differences.Comment: 19 page

Congruences via modular forms

We prove two congruences for the coefficients of power series expansions in t of modular forms where t is a modular function. As a result, we settle two recent conjectures of Chan, Cooper and Sica. Additionally, we provide a table of congruences for numbers which appear in similar power series expansions and in the study of integral solutions of Apery-like differential equations.Comment: 8 pages, revised version, to appear in Proceedings of the AM

M_2-rank differences for partitions without repeated odd parts

We prove formulas for the generating functions for M_2-rank differences for partitions without repeated odd parts. These formulas are in terms of modular forms and generalized Lambert series.Comment: 18 page